Antihyperalgesic Properties of Honokiol in Inflammatory Pain Models by Targeting of NF-κB and Nrf2 Signaling

Honokiol alleviates monosodium urate-induced gouty pain by inhibiting voltage-gated proton channels in mice

OBJECTIVE

To investigate whether honokiol (HNK) acted as an analgesic in connection with inhibiting the voltage-gated proton channel (Hv1).

METHODS

The model of gouty arthritis was induced by injecting monosodium urate (MSU) crystals into the hind ankle joint of mice. HNK was given by intragastric administration. Ankle swelling degree and mechanical allodynia were evaluated using ankle joint circumference measurement and von Frey filaments, respectively. Hv1 current, tail current, and action potential in dorsal root ganglion (DRG) neurons were recorded with patch-clamp techniques.

RESULTS

HNK (10, 20, 40 mg/kg) alleviated inflammatory response and mechanical allodynia in a dose-dependent manner. In normal DRG neurons, 50 µM Zn2+ or 2-GBI significantly inhibited the Hv1 current and the current density of Hv1 increased with increasing pH gradient. The amplitude of Hv1 current significantly increased on the 3rd after MSU treatment, and HNK dose-dependently reversed the upregulation of Hv1 current. Compared with MSU group, 40 mg/kg HNK shifted the activation curve to the direction of more positive voltage and increased reversal potential to the normal level. In addition, 40 mg/kg HNK reversed the down-regulation of tail current deactivation time constant (τtail) but did not alter the neuronal excitability of DRG neurons in gouty mice.

CONCLUSION

HNK may be a potential analgesic by inhibiting Hv1 current.

Immunostimulant, hepatoprotective, and nephroprotective potential of Bacillus subtilis (NMCC-path-14) in comparison to dexamethasone in alleviating CFA-induced arthritis

To investigate and compare efficacy as well as safety of Bacillus subtilis and dexamethasone (Dexa) in complete Freund's adjuvant (CFA)-induced arthritis, we used glucocorticoid monotherapy (Dexa 5 mg/kg/day) and B. subtilis (1 × 108 CFU/animal/day p.o) as pre-treatment and concurrent treatment for a duration of 35 days. Specific emphasis was on chronic aspect of this study since long-term use of Dexa is known to produce undesirable side effects. Treatment with Dexa significantly attenuated the arthritic symptoms but produced severe side effects like weight loss, increased mortality, immunosuppression, and altered histology of liver, kidney, and spleen. Oxidative stress was also elevated by Dexa in these organs which contributed to the damage. Treatment with B. subtilis improved symptoms of arthritis without producing any deleterious side effects as seen with Dexa therapy. Immunohistochemistry (IHC) profile revealed decreased expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), interleukin (IL)-1β, tumor necrosis factor alpha (TNF-α), and increased nuclear factor erythroid 2-related factor 2 (Nrf-2) expression by B. subtilis and Dexa treatment in ankle joint of arthritic mice. Radiological scores were also improved by both treatments. This study concludes that B. subtilis could be an effective alternative for treating arthritis than Dexa since it does not produce life-threatening side effects on prolong treatment.

Anti-inflammatory and anti-arthritic potential of Coagulansin-A: in vitro and in vivo studies

The current work was designed to evaluate the anti-inflammatory and anti-arthritic potential of Coagulansin-A (Coag-A) using mouse macrophages and arthritic mice. In the LPS-induced RAW 264.7 cells, the effects of Coag-A on the release of nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory cytokines were analyzed. In addition, the mediators involved in the nuclear factor-kappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) pathways were evaluated by the RT-qPCR and western blotting. Coag-A did not show significant cytotoxicity in the RAW 264.7 cells in the tested concentration range (1-100 µM). Coag-A significantly inhibited the production of NO, ROS, and key pro-inflammatory cytokines. The anti-inflammatory effects of Coag-A might be through inhibiting the NF-κB pathway and activating the Nrf2 pathway. In the arthritic mouse models, behavioral studies and radiological and histological analyses were performed. We found that the i.p. injection of Coag-A dose-dependently (1-10 mg/kg) reduced the Carrageenan-induced acute inflammation in the mice. In Complete Freund's Reagent-induced arthritic mouse model, Coag-A (10 mg/kg) showed significant anti-inflammatory and anti-arthritic effects in terms of the arthritic index, hematological parameters, and synovium inflammation. After the Coag-A treatment, the bone and tissue damage was ameliorated significantly in the arthritic mice. Moreover, immunohistochemistry of mouse paw tissues revealed a significant reduction in the expression of pro-inflammatory cytokines in the NF-κB pathway, confirming Coag-A's therapeutic potential and mechanism.

Phenotypic Screening of Prospective Analgesics Among FDA-Approved Compounds using an iPSC-Based Model of Acute and Chronic Inflammatory Nociception

Classical target-based drug screening is low-throughput, largely subjective, and costly. Phenotypic screening based on in vitro models is increasingly being used to identify candidate compounds that modulate complex cell/tissue functions. Chronic inflammatory nociception, and subsequent chronic pain conditions, affect peripheral sensory neuron activity (e.g., firing of action potentials) through myriad pathways, and remain unaddressed in regard to effective, non-addictive management/treatment options. Here, a chronic inflammatory nociception model is demonstrated based on induced pluripotent stem cell (iPSC) sensory neurons and glia, co-cultured on microelectrode arrays (MEAs). iPSC sensory co-cultures exhibit coordinated spontaneous extracellular action potential (EAP) firing, reaching a stable baseline after ≈27 days in vitro (DIV). Spontaneous and evoked EAP metrics are significantly modulated by 24-h incubation with tumor necrosis factor-alpha (TNF-α), representing an inflammatory phenotype. Compared with positive controls (lidocaine), this model is identified as an "excellent" stand-alone assay based on a modified Z' assay quality metric. This model is then used to screen 15 cherry-picked, off-label, Food and Drug Administration (FDA)-approved compounds; 10 of 15 are identified as "hits". Both hits and "misses" are discussed in turn. In total, this data suggests that iPSC sensory co-cultures on MEAs may represent a moderate-to-high-throughput assay for drug discovery targeting inflammatory nociception.

Daphnetin alleviates neuropathic pain in chronic constrictive injury rats via regulating the NF-κB dependent CXCL1/CXCR2 signaling pathway

CONTEXT

Daphnetin is a natural product with anti-inflammatory, antioxidant, and neuroprotective properties. Reports have found that it has a strong analgesic effect; however, its analgesic mechanism is unknown.

OBJECTIVE

We explored the effect and mechanism of daphnetin on neuropathic pain (NP).

MATERIALS AND METHODS

The rat model of NP was established by ligation of the sciatic nerve. Male Sprague-Dawley rats were divided into six groups: Control, Model, Sham, morphine (0.375 mg/kg), and daphnetin (0.0625 and 0.025 mg/kg). Rats were intrathecally injected with drugs or normal saline once daily for three days. Hyperalgesia was evaluated by mechanical withdrawal threshold (MWT) and thermal withdrawal threshold (TWT). Protein levels were detected using ELISA, immunofluorescence, and western blotting.

RESULTS

Compared to the Model group, daphnetin improved TWT (46.70 °C vs. 42.20 °C) and MWT (45.60 g vs. 23.60 g), reduced the expression of interleukin-1β (0.99 ng/g vs. 1.42 ng/g), interleukin-6 (0.90 ng/g vs. 1.52 ng/g), and tumor necrosis factor-α (0.93 ng/g vs. 1.52 ng/g) in the sciatic nerve. Daphnetin decreased the expression of toll-like receptor 4 (TLR4) (0.47-fold), phosphorylated inhibitor of NF-κB (p-IKBα) (0.29-fold), nuclear factor kappaB (NF-κB) (0.48-fold), glial fibrillary acidic protein (GFAP) (0.42-fold), CXC chemokine ligand type 1 (CXCL1) (0.84-fold), CXC chemokine receptor type 2 (CXCR2) (0.78-fold) in the spinal cord.

DISCUSSION AND CONCLUSIONS

Daphnetin alleviates NP by inhibiting inflammation and astrocyte activation in the spinal cord, providing theoretical support for the extensive clinical treatment of NP.

Preparation, characterization, and pharmacological application of oral Honokiol-loaded solid lipid nanoparticles for diabetic neuropathy

Honokiol is a phytochemical component with a variety of pharmacological properties. However, the major limitation of Honokiol is its poor solubility and low oral bioavailability. In this study, we formulated and characterized oral Honokiol-loaded solid lipid nanoparticles (SLNs) to enhance bioavailability and then evaluated their effectiveness in experimental diabetic neuropathy (DN). The finalized formulation has a spherical morphology, a particle size (PS) of 121.31 ± 9.051 nm, a polydispersity index (PDI) of 0.249 ± 0.002, a zeta potential (ZP) of -20.8 ± 2.72 mV, and an entrapment efficiency (% EE) of 88.66 ± 2.30 %. In-vitro release data shows, Honokiol-SLNs displayed a sustained release profile at pH (7.4). The oral bioavailability of Honokiol-SLNs was remarkably greater (8-fold) than Honokiol-Pure suspension. The neuroprotective property of Honokiol-SLNs was initially demonstrated against hydrogen peroxide H2O2-stimulated PC12 (pheochromocytoma) cells. Furthermore, results of in-vivo studies demonstrated that treatment with Honokiol-SLNs significantly (p < 0.001) suppressed oxidative stress by inhibition of nuclear factor kappa B (NF-κB) and significant (p < 0.001) upregulation of nuclear factor-erythroid 2-related factor 2 (Nrf2) signaling in the spinal cord. The expression of transient receptor potential melastatin 8(TRPM8) and transient receptor potential vanilloid 1 (TRPV1) was significantly (p < 0.001) downregulated. Honokiol-SLNs inhibited apoptosis by significant (p < 0.001) downregulation of cleaved caspase-3 expression in the spinal cord. These findings demonstrate that Honokiol-SLNs providedbetter neuroprotection in DN because of higher oral bioavailability.

Honokiol-Rich Magnolia officinalis Bark Extract Attenuates Trauma-Induced Neuropathic Pain

Neuropathic pain (NP) affects about 8% of the general population. Current analgesic therapies have limited efficacy, making NP one of the most difficult to treat pain conditions. Evidence indicates that excessive oxidative stress can contribute to the onset of chronic NP and several natural antioxidant compounds have shown promising efficacy in NP models. Thus, this study aimed to investigate the pain-relieving activity of honokiol (HNK)-rich standardized extract of Magnolia officinalis Rehder & E. Wilson bark (MOE), well known for its antioxidant and anti-inflammatory properties, in the spared nerve injury (SNI) model. The molecular mechanisms and efficacy toward neuroinflammation were investigated in spinal cord samples from SNI mice and LPS-stimulated BV2 microglia cells. MOE and HNK showed antioxidant activity. MOE (30 mg/kg p.o.) produced an antiallodynic effect in SNI mice in the absence of locomotor impairment, reduced spinal p-p38, p-JNK1, iNOS, p-p65, IL-1ß, and Nrf2 overexpression, increased IL-10 and MBP levels and attenuated the Notch signaling pathway by reducing Jagged1 and NEXT. These effects were prevented by the CB1 antagonist AM251. HNK reduced the proinflammatory response of LPS-stimulated BV2 and reduced Jagged1 overexpression. MOE and HNK, by modulating oxidative and proinflammatory responses, might represent interesting candidates for NP management.

Effects of Natural Product-Derived Compounds on Inflammatory Pain via Regulation of Microglial Activation

Inflammatory pain is a type of pain caused by tissue damage associated with inflammation and is characterized by hypersensitivity to pain and neuroinflammation in the spinal cord. Neuroinflammation is significantly increased by various neurotransmitters and cytokines that are expressed in activated primary afferent neurons, and it plays a pivotal role in the development of inflammatory pain. The activation of microglia and elevated levels of pro-inflammatory cytokines are the hallmark features of neuroinflammation. During the development of neuroinflammation, various intracellular signaling pathways are activated or inhibited in microglia, leading to the regulation of inflammatory proteins and cytokines. Numerous attempts have been conducted to alleviate inflammatory pain by inhibiting microglial activation. Natural products and their compounds have gained attention as potential candidates for suppressing inflammatory pain due to verified safety through centuries of use. Many studies have also shown that natural product-derived compounds have the potential to suppress microglial activation and alleviate inflammatory pain. Herein, we review the literature on inflammatory mediators and intracellular signaling involved in microglial activation in inflammatory pain, as well as natural product-derived compounds that have been found to suppress microglial activation. This review suggests that natural product-derived compounds have the potential to alleviate inflammatory pain through the suppression of microglial activation.

Suppression of MAPK/NF-kB and activation of Nrf2 signaling by Ajugarin-I in EAE model of multiple sclerosis

Multiple sclerosis (MS) is a debilitating neurodegenerative autoimmune disease of the central nervous system (CNS). The current study aimed to investigate the neuroprotective properties of Ajugarin-I (Aju-I) against the experimental autoimmune encephalomyelitis (EAE) model of MS and explored the underlying mechanism involved. The protective potential of Aju-I was first confirmed against glutamate-induced HT22 cells and hydrogen peroxide (H₂ O₂ )-induced BV2 cells. Next, an EAE model has been established to investigate the mechanisms of MS and identify potential candidates for MS treatment. The behavioral results demonstrated that Aju-I post-immunization treatment markedly reduced the EAE-associated clinical score, motor impairment, and neuropathic pain. Evans blue and fluorescein isothiocyanate extravasation in the brain were markedly reduced by Aju-I. It effectively restored the EAE-associated histopathological changes in the brain and spinal cord. It markedly attenuated EAE-induced inflammation in the CNS by reducing the expression levels of p-38/JNK/NF-κB but increased the expression of IkB-α. It suppressed oxidative stress by increasing the expression of Nrf2 but decreasing the expression of keap-1. It suppressed EAE-induced apoptosis in the CNS by regulating Bax/Bcl-2 and Caspase-3 expression. Taken together, this study suggests that Aju-I treatment exhibits neuroprotective properties in the EAE model of MS via regulation of MAPK/NF-κB, Nrf2/Keap-1, and Bcl2/Bax signaling.

New advances in Nrf2-mediated analgesic drugs

BACKGROUND

Oxidative stress is an inevitable process that occurs during life activities, and it can participate in the development of inflammation. Although great progress has been made according to research examining analgesic drugs and therapies, there remains a need to develop new analgesic drugs to fill certain gaps in both the experimental and clinical space.

PURPOSE

This review reports the research and preclinical progress of this class of analgesics by summarizing known nuclear factor E-2-related factor-2 (Nrf2) pathway-modulating substances.

STUDY DESIGN

We searched and reported experiments that intervene in the Nrf2 pathway and its various upstream and downstream molecules for analgesic therapy.

METHODS

The medical literature database (PubMed) was searched for experimental studies examining the reduction of pain in animals through the Nrf2 pathway, the research methods were analyzed, and the pathways were classified and reported according to the pathway of these experimental interventions.

RESULTS

Humans have identified a variety of substances that can fight pain by regulating the expression of Nrf2 and its upstream and downstream pathways.

CONCLUSION

The Nrf2 pathway exerts anti-inflammatory activity by regulating oxidative stress, thereby playing a role in the fight against pain.

In Vitro and In Silico Studies of Neolignans from Magnolia grandiflora L. Seeds against Human Cannabinoids and Opioid Receptors

Magnolia grandiflora L. (Magnoliaceae) is a plant of considerable medicinal significance; its flowers and seeds have been used in various traditional remedies. Radioligand binding assays of n-hexane seeds extract showed displacement of radioligand for cannabinoid (CB1 and CB2) and opioid δ (delta), κ (kappa), and µ (mu) receptors. Bioactivity-guided fractionation afforded 4-O-methylhonokiol (1), magnolol (2), and honokiol (3), which showed higher binding to cannabinoid rather than opioid receptors in radioligand binding assays. Compounds 1-3, together with the dihydro analog of 2 (4), displayed selective affinity towards CB2R (K_i values of 0.29, 1.4, 1.94, and 0.99 μM, respectively), compared to CB1R (K_i 3.85, 17.82, 14.55, and 19.08 μM, respectively). An equal mixture of 2 and 3 (1:1 ratio) showed additive displacement activity towards the tested receptors compared to either 2 or 3 alone, which in turn provides an explanation for the strong displacement activity of the n-hexane extract. Due to the unavailability of an NMR or X-ray crystal structure of bound neolignans with the CB1 and CB2 receptors, a docking study was performed to predict ligand-protein interactions at a molecular level and to delineate structure-activity relationships (SAR) of the neolignan analogs with the CB1 and CB2 receptors. The putative binding modes of neolignans 1-3 and previously reported related analogs (4, 4a, 5, 5a, 6, 6a, and 6b) into the active site of the CB1 and CB2 receptors were assessed for the first time via molecular docking and binding free-energy (∆G) calculations. The docking and ∆G results revealed the importance of a hydroxyl moiety in the molecules that forms strong H-bonding with Ser383 and Ser285 within CB1R and CB2R, respectively. The impact of a shift from a hydroxyl to the methoxy group on experimental binding affinity to CB1R versus CB2R was explained through ∆G data and the orientation of the alkyl chain within the CB1R. This comprehensive SAR, influenced by the computational study and the observed in vitro displacement binding affinities, has indicated the potential of magnolia neolignans for developing new CB agonists for potential use as analgesics, anti-inflammatory agents, or anxiolytics.

Potential applications of PEGylated green gold nanoparticles in cyclophosphamide-induced cystitis

We investigated the effect of green tea extract PEGylated gold nanoparticles (P-AuNPs) making use of its targeted and sustained drug delivery against cyclophosphamide (CYP)-induced cystitis. AuNPs were synthesized by reduction reaction of gold salts with green tea extract following the concept of green synthesis. Mostly spherical-shaped P-AuNPs were synthesized with an average size of 14.3 ± 3.3 nm. Pre-treatment with P-AuNPs (1, 10 mg/kg, i.p.) before CYP (150 mg/kg, i.p.) challenge suggested its uroprotective properties. P-AuNPs significantly reversed all pain-like behaviours and toxicities produced by CYP resulting in a decreased aspartate aminotransferase, alanine aminotransferase, C-reactive protein, and creatinine level. P-AuNPs increased anti-oxidant system by increasing the level of reduced glutathione, glutathione-S-transferase, catalase and superoxide dismutase, and reduced nitric oxide production in bladder tissue. Additionally, it attenuated hypokalaemia and hyponatremia, along with a decrease in Evans blue content in bladder tissue and peritoneal cavity. CYP-induced bladder tissue damage observed by macroscopic and histological findings were remarkably attenuated by P-AuNPs, along with reduced fibrosis of collagen fibre in bladder smooth muscles shown by Masson's trichrome staining. Additionally, alterations in hematological parameters and clinical scoring were also prevented by P-AuNPs suggesting its uroprotective effect.

Syringaresinol Alleviates Oxaliplatin-Induced Neuropathic Pain Symptoms by Inhibiting the Inflammatory Responses of Spinal Microglia

Oxaliplatin-induced peripheral neuropathy (OIPN) is a serious side effect that impairs the quality of life of patients treated with the chemotherapeutic agent, oxaliplatin. The underlying pathophysiology of OIPN remains unclear, and there are no effective therapeutics. This study aimed to investigate the causal relationship between spinal microglial activation and OIPN and explore the analgesic effects of syringaresinol, a phytochemical from the bark of Cinnamomum cassia, on OIPN symptoms. The causality between microglial activation and OIPN was investigated by assessing cold and mechanical allodynia in mice after intrathecal injection of the serum supernatant from a BV-2 microglial cell line treated with oxaliplatin. The microglial inflammatory response was measured based on inducible nitric oxide synthase (iNOS), phosphorylated extracellular signal-regulated kinase (p-ERK), and phosphorylated nuclear factor-kappa B (p-NF-κB) expression in the spinal dorsal horn. The effects of syringaresinol were tested using behavioral and immunohistochemical assays. We found that oxaliplatin treatment activated the microglia to increase inflammatory responses, leading to the induction of pain. Syringaresinol treatment significantly ameliorated oxaliplatin-induced pain and suppressed microglial expression of inflammatory signaling molecules. Thus, we concluded that the analgesic effects of syringaresinol on OIPN were achieved via the modulation of spinal microglial inflammatory responses.

Anti-nociceptive effects of magnolol via inhibition of TRPV1/P2Y and TLR4/NF-κB signaling in a postoperative pain model

AIMS

The current study explored the anti-nociceptive activity of magnolol in post-incisional inflammatory nociceptive pain.

MAIN METHODS

Preliminary, the anti-inflammatory, antioxidant, and cytoprotective potential of magnolol were confirmed against hydrogen peroxide (H₂O₂)-induced PC12 cells. Next, an in-vivo model of planter incision surgery was established in BALB/c mice. Tramadol 50 mg/kg intraperitoneal (i.p.) and magnolol (0.1, 1, 10 mg/kg i.p. + 10 mg/kg intra planter) were administered after plantar incision surgery and behavior parameters were measured.

KEY FINDINGS

The results indicate that magnolol significantly suppressed post-incision-induced mechanical allodynia, thermal hyperalgesia, and paw edema. Magnolol promisingly inhibited post-incision induces nitric oxide (NO), malondialdehyde (MDA), eosinophil peroxidase (EPO), and neutrophil infiltration. Magnolol strongly attenuated post-incision inducing the release of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and inhibited deoxyribonucleic acid (DNA) fragmentation. Magnolol markedly reverses post-incisional histopathological changes and biochemical composition of the incised paw. Magnolol markedly down-regulated post-incisional increase expression of transient receptor potential vanilloid 1 (TRPV1), purinergic (P2Y) nociceptors as well as toll-like receptor 4 (TLR4), nuclear factor kappa light chain enhancer of activated B cell (NF-κB), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) while upregulating the expression of inhibitor of nuclear kappa B alpha (IκB-α).

SIGNIFICANCE

The present study strongly suggests that magnolol significantly suppressed post-incisional inflammatory nociceptive pain by targeting TRPV1/P2Y and TLR4/NF-κB signaling.

Anti-Inflammatory and Anti-Rheumatic Potential of Selective Plant Compounds by Targeting TLR-4/AP-1 Signaling: A Comprehensive Molecular Docking and Simulation Approaches

Plants are an important source of drug development and numerous plant derived molecules have been used in clinical practice for the ailment of various diseases. The Toll-like receptor-4 (TLR-4) signaling pathway plays a crucial role in inflammation including rheumatoid arthritis. The TLR-4 binds with pro-inflammatory ligands such as lipopolysaccharide (LPS) to induce the downstream signaling mechanism such as nuclear factor κappa B (NF-κB) and mitogen activated protein kinases (MAPKs). This signaling activation leads to the onset of various diseases including inflammation. In the present study, 22 natural compounds were studied against TLR-4/AP-1 signaling, which is implicated in the inflammatory process using a computational approach. These compounds belong to various classes such as methylxanthine, sesquiterpene lactone, alkaloid, flavone glycosides, lignan, phenolic acid, etc. The compounds exhibited different binding affinities with the TLR-4, JNK, NF-κB, and AP-1 protein due to the formation of multiple hydrophilic and hydrophobic interactions. With TLR-4, rutin had the highest binding energy (−10.4 kcal/mol), poncirin had the highest binding energy (−9.4 kcal/mol) with NF-κB and JNK (−9.5 kcal/mol), respectively, and icariin had the highest binding affinity (−9.1 kcal/mol) with the AP-1 protein. The root means square deviation (RMSD), root mean square fraction (RMSF), and radius of gyration (RoG) for 150 ns were calculated using molecular dynamic simulation (MD simulation) based on rutin’s greatest binding energy with TLR-4. The RMSD, RMSF, and RoG were all within acceptable limits in the MD simulation, and the complex remained stable for 150 ns. Furthermore, these compounds were assessed for the potential toxic effect on various organs such as the liver, heart, genotoxicity, and oral maximum toxic dose. Moreover, the blood–brain barrier permeability and intestinal absorption were also predicted using SwissADME software (Lausanne, Switzerland). These compounds exhibited promising physico-chemical as well as drug-likeness properties. Consequently, these selected compounds portray promising anti-inflammatory and drug-likeness properties.

Prostaglandin D2 Attenuates Lipopolysaccharide-Induced Acute Lung Injury through the Modulation of Inflammation and Macrophage Polarization

Acute lung injury (ALI) is a well-known respiratory disease and a leading cause of death worldwide. Despite advancements in the medical field, developing complete treatment strategies against this disease is still a challenge. In the current study, the therapeutic role of prostaglandin D2 (PGD2) was investigated on lipopolysaccharide (LPS)-induced lung injury in mice models and RAW264.7 macrophages through anti-inflammatory, histopathology, immunohistochemistry, and TUNEL staining. The overproduction of cytokines by RAW264.7 macrophages was observed after stimulation with LPS. However, pretreatment with PGD2 decreased the production of cytokines. The level of inflammatory markers was significantly restored in the PGD2 treatment group (TNF-α = 58.6 vs. 78.5 pg/mL; IL-1β = 29.3 vs. 36.6 pg/mL; IL-6 = 75.4 vs. 98.2 pg/mL; and CRP = 0.84 vs. 1.14 ng/mL). The wet/dry weight ratio of the lungs was quite significant in the disease control (LPS-only treatment) group. Moreover, the histological changes as determined by haematoxylin and eosin (H&E) staining clearly showed that PGD2 treatment maintains the lung tissue architecture. The iNOS expression pattern was increased in lung tissues of LPS-treated animals, whereas, in mice treated with PGD2, the expression of iNOS protein decreased. Flow cytometry data demonstrated that LPS intoxication enhanced apoptosis, which significantly decreased with PGD2 treatment. In conclusion, all these observations indicate that PGD2 provides an anti-inflammatory response in RAW264.7 macrophages and in ALI, and they suggest a therapeutic potential in lung pathogenesis.

Suppression of NF-κB signaling by ECN in an arthritic model of inflammation

Background

The 7β-(3-ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid isolated from the Tussilago farfara Linneaus (Asteraceae), was evaluated against acute Carrageenan and chronic complete Freund’s adjuvant (CFA)-induced arthritis in mice.

Methods

Acute and chronic arthritis were induced by administering Carrageenan and CFA to the intraplantar surface of the mouse paw. Edema, mechanical allodynia, mechanical hyperalgesia, and thermal hyperalgesia were assessed in the paw. Similarly, histological and immunohistological parameters were assessed following arthritis induced by CFA. Antioxidants, inflammatory cytokines, and oxidative stress markers were also studied in all the treated groups.

Results

The ECN treatment significantly attenuated edema in the paw and elevated the nocifensive threshold following induction of this inflammatory model. Furthermore, ECN treatment markedly improved the arthritis index and distress symptoms, while attenuating the CFA-induced edema in the paw. ECN treatment also improved the histological parameters in the paw tissue compared to the control. At the same time, there was a significant reduction in edema and erosion in the ECN-treated group, as measured by radiographic analysis. Using the Comet’s assay, we showed that ECN treatment protected the DNA from chronic CFA-induced arthritis. Immunohistochemistry analysis showed a marked decrease in the expression level of p-JNK (phosphorylated C-Jun N-terminal kinase), NF-κB (Nuclear factor-kappa B), COX-2 (Cyclooxygenase-2), and TNF-α (Tumour necrosis factor-alpha) compared to the CFA-treated group. Biophysical analysis involving molecular docking, molecular dynamics simulations, and binding free energies of ECN were performed to explore the underlying mechanism.

Conclusion

ECN exhibited significant anti-inflammatory and anti-arthritic activity against Carrageenan and CFA-induced models.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03629-7.

Magnolol prevented brain injury through the modulation of Nrf2-dependent oxidative stress and apoptosis in PLP-induced mouse model of multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated chronic inflammatory demyelinating disease of the central nervous system (CNS). The aim of the current study was to investigate the effects of magnolol in an experimental autoimmune encephalomyelitis (EAE) model of MS in female mice. Magnolol (0.1, 1, and 10 mg/kg) was administered once daily for 21 days after immunization of mice. Magnolol post-immunization treatment significantly reversed clinical scoring, EAE-associated pain parameters, and motor dysfunction in a dose-dependent manner. Magnolol treatment significantly inhibited oxidative stress by reducing malondialdehyde (MDA), nitric oxide (NO) production, and myeloperoxidase (MPO) activity while enhancing the level of antioxidants such as reduced glutathione (GSH), glutathione-S-transferase (GST), catalase, and superoxide dismutase (SOD) in the brain and spinal cord. It reduced cytokine levels in the brain and spinal cord. It suppressed CD8+ T cells frequency in the spleen tissue. Magnolol remarkably reversed the EAE-associated histopathology of the brain and spinal cord tissue. Magnolol significantly intensifies the antioxidant defense system by enhancing the expression level of nuclear factor erythroid 2-related factor (Nrf2) while decreasing the expression of inducible nitric oxide synthase (iNOS) and cleaved-caspase-3 in the brain. Molecular docking results showed that magnolol possesses a better binding affinity for Nrf2, iNOS, and caspase-3 proteins. Taken together, the present study demonstrated that magnolol has significant neuroprotective properties in EAE via inhibition of oxidative stress.

N-(benzylidene)-2-((2-hydroxynaphthalen-1-yl)diazenyl)benzohydrazides (1-2) (NCHDH and NTHDH) attenuate DMBA-induced breast cancer via Nrf2/NF-κB/apoptosis signaling

The present study investigated the effect of the N-(benzylidene)-2-((2-hydroxynaphthalen-1-yl)diazenyl)benzohydrazides (1-2) (NCHDH and NTHDH) against breast cancer using in vitro and in vivo approaches. The NCHDH and NTHDH significantly inhibited the growth of the MCF-7 cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. The NCHDH and NTHDH treatment significantly inhibited the tumor size, tumor weight, and tumor volume, while it enhanced the survival and tumor free survival rate following 7,12-Dimethylbenz[a]anthracene (DMBA)-induced breast cancer. The NCHDH and NTHDH markedly attenuated the oxidative stress markers and induced the antioxidant level. The enzyme-linked immunosorbent assay (ELISA) showed significant reduction in the inflammatory cytokines production compared with the DMBA control. The NCHDH and NTHDH treatment significantly improved the histological features using hematoxylin and eosin (H and E) staining, Masson's trichrome, PAS (periodic acid Schiff), and Toluidine blue staining compared with the DMBA-induced group. The NCHDH and NTHDH treatment improved the hematological and serological parameters following DMBA-induced breast tumor compared with DMBA-induced group. Furthermore, the NCHDH and NTHDH treatment significantly enhanced the antioxidants signaling proteins such as nuclear factor erythroid 2-related factor 2 (Nrf2) and Heme oxygenase 1 (HO-1). The NCHDH and NTHDH enhanced the inhibitor of NF-κB (IκB) level, while it attenuated the NF-κB level. Similarly, the NCHDH and NTHDH showed marked increase in the apoptosis proteins such as Caspase-3, Caspase-9, and Bcl-2 Associated X-protein (Bax), while it inhibited the B-cell lymphoma 2 (Bcl-2) expression. In conclusion, the NCHDH and NTHDH significantly improved the DMBA-induced breast cancer via attenuating oxidative stress and inflammatory cytokines.

Physicochemical Characterizations and Pharmacokinetic Evaluation of Pentazocine Solid Lipid Nanoparticles against Inflammatory Pain Model

Pentazocine (PTZ), a narcotic-antagonist analgesic, has been extensively used in the treatment of initial carcinogenic or postoperative pain. Hepatic first-pass metabolism results in low oral bioavailability and high dose wastage. Herein, 10 mg (-)-Pentazocine (HPLC-grade) was incorporated to solid lipid nanoparticles (SLNs) using a double water-oil-water (w/o/w) emulsion by solvent emulsification–evaporation technique, followed by high shear homogenization to augment its oral bioavailability, considering the lymphatic uptake. The resulting SLNs were characterized for zeta potential (ZP), particle size (PS), and polydispersity index (PDI) using a zetasizer. The entrapment efficiency (EE) and loading capacity (LC) were calculated. Chemical interactions, through the identification of active functional groups, were assessed by Fourier-transformed infrared (FTIR) spectroscopy. The nature (crystallinity) of the SLNs was determined by X-ray diffractometry (XRD). The surface morphology was depicted by transmission electron microscopy (TEM). In vitro (in Caco-2 cells) and in vivo (in male Wistar rats) investigations were carried out to evaluate the PTZ release behavior and stability, as well as the cellular permeation, cytotoxicity, systemic pharmacokinetics, antinociceptive, anti-inflammatory, and antioxidative activities of PTZ-loaded SLNs, mainly compared to free PTZ (marketed conventional dosage form). The optimized PTZ-loaded SLN2 showed significantly higher in vitro cellular permeation and negligible cytotoxicity. The in vivo bioavailability and pharmacokinetics parameters (t1/2, Cmax) of the PTZ-loaded SLNs were also significantly improved, and the nociception and inflammation, following carrageenan-induced inflammatory pain, were markedly reduced. Concordantly, PTZ-loaded SLNs showed drastic reduction in the oxidative stress (e.g., malonaldehyde (MDA)) and proinflammatory cytokines (e.g., Interleukin (IL)-1β, -6, and TNF-α). The histological features of the paw tissue following, carrageenan-induced inflammation, were significantly improved. Taken together, the results demonstrated that PTZ-loaded SLNs can improve the bioavailability of PTZ by bypassing the hepatic metabolism via the lymphatic uptake, for controlled and sustained drug delivery.

Comprehensive in vivo and in silico approaches to explore the hepatoprotective activity of poncirin against paracetamol toxicity

In the present study, poncirin was evaluated against paracetamol-induced liver injury using in vivo and computational approaches. Paracetamol was administered intraperitoneally (i.p,) to establish liver injury in mice and, subsequently, to investigate the hepatoprotective effect of poncirin (administered intraperitoneally) on liver injury. The effect of poncirin was evaluated against the liver injury markers and inflammatory cytokines. Similarly, in the present study, the antioxidants and oxidative stress parameters were also assessed following paracetamol-induced liver injury. The histological studies following liver injury were also assessed using H and E staining, Masson's trichrome staining, and periodic acid-Schiff staining. Similarly, the computational approach was used to assess the pharmacokinetic parameters of poncirin and its interaction with various protein targets. Poncirin markedly improved the antioxidant enzymes while attenuated the oxidative stress markers and inflammatory cytokines. Poncirin also markedly improved hematological parameters. Furthermore, poncirin treatment significantly improved the histological parameters using H and E staining, Masson's trichrome, and PAS staining compared to the control. Poncirin treatment also improved the liver function tests and liver synthetic activity compared to paracetamol treated group. The immunohistochemistry analysis revealed significant decrease in the inflammatory signaling protein such as nuclear factor kappa light chain enhancer of activated B cells (NF-κB), Jun N-terminal kinase (JNK), and cyclooxygenase-2 (COX-2) expression level compared to the paracetamol treated group. Computational analysis (molecular docking and molecular dynamic simulation) showed significant binding affinity of poncirin with the NF-κB, JNK, COX-2, IL-1β, IL-6, and TNF-α via multiple hydrophilic and hydrophobic binds. Similarly, the SwissADME software revealed that poncirin follows various drug-likeness rules and exhibited better pharmacokinetic parameters. Poncirin improved the sign and symptoms associated with liver injury using both in vivo and computational approaches.

Targeting NF-κB pathway by dietary lignans in inflammation: expanding roles of gut microbiota and metabolites

Inflammation is a major factor affecting human health. Nuclear factor-kappa B (NF-κB) plays a vital role in the development of inflammation, and the promoters of most inflammatory cytokine genes have NF-κB-binding sites. Targeting NF-κB could be an exciting route for the prevention and treatment of inflammatory diseases. As important constituents of natural plants, lignans are proved to have numerous biological functions. There are growing pieces of evidence demonstrate that lignans have the potential anti-inflammatory activities. In this work, the type, structure and source of lignans and the influence on mitigating the inflammation are systematically summarized. This review focuses on the targeting NF-κB signaling pathway in the inflammatory response by different lignans and their molecular mechanisms. Lignans also regulate gut microflora and change gut microbial metabolites, which exert novel pathway to prevent NF-κB activation. Taken together, lignans target NF-κB with various mechanisms to inhibit inflammatory cytokine expressions in the inflammatory response. It will provide a scientific theoretical basis for further research on the anti-inflammatory effects of lignans and the development of functional foods.

A honokiol-mediated robust coating for blood-contacting devices with anti-inflammatory, antibacterial and antithrombotic properties

Thrombus, bacterial infections, and severe inflammation are still serious problems that have to be faced with blood-contacting materials. However, it is a great challenge to simultaneously meet the above functional requirements in a simple, economical and efficient method. As such, we put forward a robust and versatile coating strategy by covalently modifying the multi-pharmacological drug honokiol (HK) with an amine-rich polydopamine/polyethyleneimine coating, through which anticoagulant, antibacterial and anti-inflammatory properties were obtained (DPHc) simultaneously. The amine content in the DPHc coating was lower than the detection limit, while it contained abundant phenolic hydroxyl groups (49 μmol cm-2). Meanwhile, the 30 day drug release test confirmed that the drug was firmly modified on the surface of the coating without release. A systematic in vitro and ex vivo evaluation confirmed that the coating had significant anti-thrombotic properties. The antibacterial rates of the DPHc coating against Staphylococcus aureus and Escherichia coli reached 99.98% and 99.99%, respectively. In addition, subcutaneous implantation indicated that the DPHc coating also has excellent histocompatibility. To the best of our knowledge, this is the first study using HK as a coating material that can not only combat thrombosis and infection but also significantly inhibit inflammation associated with the use of blood-contacting materials, thus expanding the application of HK in the field of biomaterials.

The rich pharmacological activities of Magnolia officinalis and secondary effects based on significant intestinal contributions

ETHNOPHARMACOLOGICAL RELEVANCE

Magnolia officinalis Cortex (M. officinalis) is a traditional herbal drug widely used in Asian countries. Depending on its multiple biological activities, M. officinalis is used to regulate gastrointestinal (GI) motility, relieve cough and asthma, prevent cardiovascular and cerebrovascular diseases, and treat depression and anxiety.

AIM OF THE REVIEW

We aimed to review the abundant form of pharmacodynamics activity and potential mechanisms of action of M. officinalis and the characteristics of the internal processes of the main components. The potential mechanisms of local and distance actions of M. officinalis based on GI tract was provided, and it was used to reveal the interconnections between traditional use, phytochemistry, and pharmacology.

MATERIALS AND METHODS

Published literatures about M. officinalis and its main components were collected from several scientific databases, including PubMed, Elsevier, ScienceDirect, Google Scholar and Web of Science etc. RESULTS: M. officinalis was shown multiple effects including effects on digestive system, respiratory system, central system, which is consistent with traditional applications, as well as some other activities such as cardiovascular system, anticancer, anti-inflammatory and antioxidant effects and so on. The mechanisms of these activities are abundant. Its chief ingredients such as magnolol and honokiol can be metabolized into active metabolites in vivo, which can increase water solubility and bioavailability and exert pharmacological activity in the whole body. In the GI tract, M. officinalis and its main ingredient can regulate GI hormones and substance metabolism, protect the intestinal barrier and affect the gut microbiota (GM). These actions are effective to improve local discomfort and some distal symptoms such as depression, asthma, or metabolic disorders.

CONCLUSIONS

Although M. officinalis has rich pharmacological effects, the GI tract makes great contributions to it. The GI tract is not only an important place for absorption and metabolism but also a key site to help M. officinalis exert local and distal efficacy. Pharmacodynamical studies on the efficacies of distal tissues based on the contributions of the GI tract hold great potential for understanding the benefits of M. officinalis and providing new ideas for the treatment of important diseases.

Anti-neuropathic pain activity of a cationic palladium (II) dithiocarbamate by suppressing the inflammatory mediators in paclitaxel-induced neuropathic pain model

BACKGROUND

Neuropathic pain is a chronic pain state that negatively impacts the quality of life. Currently, available therapies for the treatment of neuropathic pain often lack efficacy and tolerability. Therefore, the search for novel drugs is crucial to obtain treatments that effectively suppress neuropathic pain.

OBJECTIVES

The present study was undertaken to investigate the antinociceptive properties of (1,4-bis-(diphenylphosphino) butane) palladium (II) chloride monohydrate (Compound 1) in a paclitaxel (PTX)-induced neuropathic pain model.

METHODS

Initially, behavioral tests such as mechanical and cold allodynia as well as thermal and tail immersion hyperalgesia were performed to investigate the antinociceptive potential of Compound 1 (5 and 10 mg/kg, b.w). RT-PCR was performed to determine the effect of Compound 1 on the mRNA expression level of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and proinflammatory cytokines such as tumor necrosis factor-alpha (TNF)-α, interleukin (IL)-1β, and IL-6. In addition, antioxidant protein, nitric oxide (NO), and malondialdehyde (MDA) levels were also determined.

RESULTS

The results demonstrated that once-daily dosing of Compound 1 significantly suppressed the PTX-induced behavioral pain responses dose-dependently. The mRNA gene expressions of iNOS, COX-2, and inflammatory cytokines were markedly reduced by Compound 1. Furthermore, it enhanced the level of antioxidant enzymes and lowered the level of MDA and NO production.

CONCLUSION

These findings suggest that the antinociceptive potential of Compound 1 in the PTX-induced neuropathic pain model is via suppression of oxidative stress and inflammation. Thus, Compound 1 might be a potential candidate for the therapeutic management of PTX induced neuropathic pain.

Withametelin, a novel phytosterol, alleviates neurological symptoms in EAE mouse model of multiple sclerosis via modulation of Nrf2/HO-1 and TLR4/NF-κB signaling

Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disorder of the central nervous system (CNS) that remains incurable. Withametelin (WMT), a phytosterol, showed diverse biological activities isolated from the leaves of Datura innoxa. In the present study, we used an in vitro model of HT22 and BV-2 cell lines and an in vivo murine model of MS, experimental autoimmune encephalomyelitis (EAE), to explore the antioxidant and anti neuroinflammatory potential of WMT. The results showed that pretreatment with WMT markedly inhibited H₂O₂-induced cytotoxicity and oxidative stress in a dose-dependent manner. Correspondingly, WMT post-immunization treatment significantly attenuated EAE-induced clinical score, weight loss, neuropathic pain behaviors, and motor dysfunction. It markedly lowers EAE-induced elevated circulating leucocytes, spinal deformity, and splenomegaly. It strikingly inhibited the Evans blue and FITC extravasation in the brain. It remarkably reversed the EAE-induced histopathological alteration of the brain, spinal cord, eye, and optic nerve. It significantly intensified the antioxidant defense mechanism by improving the expression level of nuclear factor-erythroid-related factor-2 (Nrf2), heme-oxygenase-1 (HO-1) but reducing the expression level of the Kelch-like-ECH-associated-protein-1 (keap-1), inducible-nitric-oxide-synthase (iNOS) in the CNS. Likewise, it markedly suppressed neuroinflammation by reducing the expression level of toll-like-receptor 4 (TLR4), nuclear-factor-kappa-B (NF-κB), activator-protein-1 (AP-1) but increased the expression level IkB-α in the CNS. Furthermore, molecular dynamics simulations and MMPBSA binding free energies were determined to validate the dynamic stability of complexes and shed light on the atomic level intermolecular interaction energies. Taken together, this study showed that WMT has significant neuroprotective potential in EAE via modulation of Nrf2 mediated-oxidative stress and NF-κB mediated inflammation.

Electroacupuncture Attenuates Cancer-Induced Bone Pain via NF-κB/CXCL12 Signaling in Midbrain Periaqueductal Gray

Electroacupuncture (EA) is effective in various chronic pains. NF-κB and CXCL12 modulate the formation of chronic pain. Herein, we hypothesized that EA alleviates cancer-induced bone pain (CIBP) through NF-κB/CXCL12 axis in midbrain periaqueductal gray (PAG), which participates in "top-down" pain modulatory circuits. In order to filter the optimum EA frequency for CIBP treatment, 2, 100, or 2/100 Hz EA was set up. In addition, ipsilateral, contralateral, and bilateral EA groups were established to affirm the optimal EA scheme. Bilateral 2/100 Hz EA was considered as the optimal therapeutic scheme and was applied in a subsequent experiment. Western blotting along with immunofluorescence illustrated that CIBP induces a rapid and substantial increase in CXCL12 protein level and NF-κB phosphorylation in vlPAG from day 6 to day 12. Anti-CXCL12 neutralizing antibody and pAAV-U6-shRNA(CXCL12)-CMV-EGFP-WPRE in vlPAG remarkably improved the mechanical pain threshold of the hind paw in CIBP model relative to the control. EA inhibited the upregulation of pNF-κB and CXCL12 in vlPAG of CIBP. The recombinant CXCL12 and pAAV-CMV-CXCL12-EF1a-EGFP-3Xflag-WPRE reversed the abirritation of EA in the CIBP rat model. NF-κB phosphorylation mediated-CXCL12 expression contributed to CIBP allodynia, whereas EA suppressed NF-κB phosphorylation in CIBP. According to the above evidence, we conclude that bilateral 2/100 Hz EA is an optimal therapeutic scheme for CIBP. The abirritation mechanism of EA might reduce the expression of CXCL12 by inhibiting the activation of NF-κB, which might lead to the restraint of descending facilitation of CIBP.

Anti-allergic activities of Umbelliferone against histamine- and Picryl chloride-induced ear edema by targeting Nrf2/iNOS signaling in mice

BACKGROUND

The current study was aimed to investigate the anti-allergic activities of the Umbelliferone (UMB) against the acute Histamine and chronic Picryl chloride (PiCl)-induced allergy in mice. UMB is a coumarin derivative (isolated from Angelica decursiva) found in various parts of the plants such as flowers, roots and, stems isolated from the plants of Umbelliferae family.

METHODS

The UMB (1, 10, 50 mg/kg) was administered intraperitoneally (i.p) half an h before or 2 h after the induction of allergic ear edema. The acute ear edema was induced by histamine (intradermally, i.d), while the chronic ear edema was induced by painting the PiCl (sensitized with the toluene) on the ear. The antioxidants and oxidative stress markers were assessed. The histological changes were assessed using Hematoxylin and eosin (H and E) and giemsa staining. The immunohistochemistry studies were performed to assess the expression of the nuclear factor erythroid 2-related factor 2 (Nrf2) and inducible nitric oxide synthase (iNOS). The data was analyzed using one-way ANOVA tests followed by Tukey's test with p < 0.05 was chosen as criteria for statistical significance.

RESULTS

UMB treatment markedly reduced the allergic ear edema and ear weight compared to the negative control. Furthermore, the UMB attenuated the oxidative stress markers, while induced the antioxidants enzymes. Similarly, the UMB treatment significantly attenuated the serum immunoglobulin E (IgE) level. The UMB treatment markedly improved the histological parameters using H and E staining and Giemsa staining. The UMB administration induced the Nrf2 expression, while attenuated the iNOS expression. Furthermore, the computational analysis was performed to assess the interaction of the UMB with the various protein targets and to determine the mechanism of interaction with the target proteins.

CONCLUSION

In conclusion, the UMB treatment significantly alleviated the allergic symptoms, attenuating the oxidative stress, improved the histological features using in vivo and computational approaches.

Macrophage-derived extracellular vesicles regulates USP5-mediated HDAC2/NRF2 axis to ameliorate inflammatory pain

Emerging research has highlighted the capacity of microRNA-23a-3p (miR-23a-3p) to alleviate inflammatory pain. However, the molecular mechanism by which miR-23a-3p attenuates inflammatory pain is yet to be fully understood. Hence, the current study aimed to elucidate the mechanism by which miR-23a-3p influences inflammatory pain. Bioinformatics was initially performed to predict the inflammatory pain related downstream targets of miR-23a-3p in macrophage-derived extracellular vesicles (EVs). An animal inflammatory pain model was established using Complete Freund's Adjuvant (CFA). The miR-23a-3p expression was downregulated in the microglia of CFA-induced mice, after which the inflammatory factors were determined by ELISA. FISH and immunofluorescence were performed to analyze the co-localization of miR-23a-3p and microglia. Interestingly, miR-23a-3p was transported to the microglia via M2 macrophage-EVs, which elevated the mechanical allodynia and the thermal hyperalgesia thresholds in mice model. The miR-23a-3p downstream target, USP5, was found to stabilize HDAC2 via deubiquitination to promote its expression while inhibiting the expression of NRF2. Taken together, the key findings of the current study demonstrate that macrophage-derived EVs containing miR-23a-3p regulates the HDAC2/NRF2 axis by decreasing USP5 expression to alleviate inflammatory pain, which may provide novel therapeutic targets for the treatment of inflammatory pain.

Mechanistic evaluation of a novel cyclohexenone derivative's functionality against nociception and inflammation: An in-vitro, in-vivo and in-silico approach

The synthesis of a novel cyclohexanone derivative (CHD; Ethyl 6-(4-metohxyphenyl)-2-oxo-4-phenylcyclohexe-3-enecarboxylate) was described and the subsequent aim was to perform an in vitro, in vivo and in silico pharmacological evaluation as a putative anti-nociceptive and anti-inflammatory agent in mice. Initial in vitro studies revealed that CHD inhibited both cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) enzymes and it also reduced mRNA expression of COX-2 and the pro-inflammatory cytokines TNF-α and IL-1β. It was then shown that CHD dose dependently inhibited chemically induced tonic nociception in the abdominal constriction assay and also phasic thermal nociception (i.e. anti-nociception) in the hot plate and tail immersion tests in comparison with aspirin and tramadol respectively. The thermal test outcomes indicated a possible moderate centrally mediated anti-nociception which, in the case of the hot plate test, was pentylenetetrazole (PTZ) and naloxone reversible, implicating GABAergic and opioidergic mechanisms. CHD was also effective against both the neurogenic and inflammatory mediator phases induced in the formalin test and it also disclosed anti-inflammatory activity against the phlogistic agents, carrageenan, serotonin, histamine and xylene compared with standard drugs in edema volume tests. In silico studies indicated that CHD possessed preferential affinity for GABAA, opioid and COX-2 target sites and this was supported by molecular dynamic simulations where computation of free energy of binding also favored the formation of stable complexes with these sites. These findings suggest that CHD has prospective anti-nociceptive and anti-inflammatory properties, probably mediated through GABAergic and opioidergic interactions supplemented by COX-2 and 5-LOX enzyme inhibition in addition to reducing pro-inflammatory cytokine expression. CHD may therefore possess potentially beneficial therapeutic effectiveness in the management of inflammation and pain.

Honokiol: A naturally occurring lignan with pleiotropic bioactivities

Honokiol is the dominant biphenolic compound isolated from the Magnolia tree, and has long been considered as the active constituent of the traditional Chinese herb, 'Houpo', which is widely used to treat symptoms due to 'stagnation of qi'. Pharmacological studies have shown that honokiol possesses a wide range of bioactivities without obvious toxicity. Honokiol protects the liver, kidneys, nervous system, and cardiovascular system through reducing oxidative stress and relieving inflammation. Moreover, honokiol shows anti-diabetic property through enhancing insulin sensitivity, and anti-obese property through promoting browning of adipocytes. In vivo and in vitro studies indicated that honokiol functions as an anti-cancer agent through multiple mechanisms: inhibiting angiogenesis, promoting cell apoptosis, and regulating cell cycle. A variety of therapeutic effects of honokiol may be associated with its physiochemical properties, which make honokiol readily cross the blood brain barrier and the blood-cerebrospinal fluid barrier, with high bioavailability. In the future, more clinical researches on honokiol are needed to fully authenticate its therapeutic values.

Inhibition of NF-κB signaling and HSP70/HSP90 proteins by newly synthesized hydrazide derivatives in arthritis model

In the current study, the N-benzylidene-4-((2-hydroxynaphthalene-1-yl) diazenyl) hydrazides (NCHDH and NTHDH) were evaluated against the Carrageenan- and CFA-induced models. During the preliminary investigation, the NCHDH and NTHDH treatment showed marked anti-inflammatory and analgesic activity against the Carrageenan-induced acute model. Once the anti-inflammatory activity was established against acute Carrageenan model, the NCHDH and NTHDH were evaluated against the chronic CFA-induced arthritis model. The NCHDH and NTHDH treatment markedly attenuated the inflammatory and analgesic parameters compared to CFA-treated group. Furthermore, the increase in the oxidative stress and attenuation of antioxidant enzymes has been reported following CFA administration. However, NCHDH and NTHDH treatment significantly induced the antioxidants and attenuated the oxidative stress markers. The CFA administration showed marked tailing of DNA; however, the NCHDH- and NTHDH-treated group preserved DNA integrity. Furthermore, the histological studies showed marked alteration in the CFA-treated group; however, the NCHDH and NTHDH treatment markedly improved the histological features. The Western blot, immunohistology, and ELISA assay revealed marked increase in the Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), Jun N-terminal Kinase (JNK), TNF-α, and COX-2 levels; however, the NCHDH and NTHDH attenuated their expressions significantly. Similarly, the NCHDH and NTHDH significantly induced the mRNA expression levels of heat shock proteins. The computational analysis showed significant binding interaction with various protein targets via multiple hydrogens, and hydrophobic bonds. The in vivo pharmacokinetic study was also performed to assess the various pharmacokinetic parameters. In conclusion, the NCHDH and NTHDH treatment showed significant anti-arthritic activity against Carrageenan and CFA models.

Suppression of TRPV1/TRPM8/P2Y Nociceptors by Withametelin via Downregulating MAPK Signaling in Mouse Model of Vincristine-Induced Neuropathic Pain

Vincristine (VCR) is a widely used chemotherapy drug that induced peripheral painful neuropathy. Yet, it still lacks an ideal therapeutic strategy. The transient receptor potential (TRP) channels, purinergic receptor (P2Y), and mitogen-activated protein kinase (MAPK) signaling play a crucial role in the pathogenesis of neuropathic pain. Withametelin (WMT), a potential Phytosteroid isolated from datura innoxa, exhibits remarkable neuroprotective properties. The present investigation was designed to explore the effect of withametelin on VCR-induced neuropathic pain and its underlying molecular mechanism. Initially, the neuroprotective potential of WMT was confirmed against hydrogen peroxide (H₂O₂)-induced PC12 cells. To develop potential candidates for neuropathic pain treatment, a VCR-induced neuropathic pain model was established. Vincristine (75 μg/kg) was administered intraperitoneally (i.p.) for 10 consecutive days (day 1-10) for the induction of neuropathic pain. Gabapentin (GBP) (60 mg/kg, i.p.) and withametelin (0.1 and 1 mg/kg i.p.) treatments were given after the completion of VCR injection on the 11th day up to 21 days. The results revealed that WMT significantly reduced VCR-induced pain hypersensitivity, including mechanical allodynia, cold allodynia, and thermal hyperalgesia. It reversed the VCR-induced histopathological changes in the brain, spinal cord, and sciatic nerve. It inhibited VCR-induced changes in the biochemical composition of the myelin sheath of the sciatic nerve. It markedly downregulated the expression levels of TRPV1 (transient receptor potential vanilloid 1); TRPM8 (Transient receptor potential melastatin 8); and P2Y nociceptors and MAPKs signaling, including ERK (Extracellular Signal-Regulated Kinase), JNK (c-Jun N-terminal kinase), and p-38 in the spinal cord. It suppressed apoptosis by regulating Bax (Bcl2-associated X-protein), Bcl-2 (B-cell-lymphoma-2), and Caspase-3 expression. It considerably attenuated inflammatory cytokines, oxidative stress, and genotoxicity. This study suggests that WMT treatment suppressed vincristine-induced neuropathic pain by targeting the TRPV1/TRPM8/P2Y nociceptors and MAPK signaling.

Gastroprotective Effect of Ethanol Extracts from Bark of Magnolia officinalis on Ethanol-Induced Gastric Mucosal Damage in Rats

Background. Magnolia officinalis Rehd. and Wils. is widely used in Asian countries because of its multiple pharmacological effects. This study investigated the gastroprotective effect and mechanisms of the ethanol extracts from the bark of Magnolia officinalis (MOE) against ethanol-induced gastric mucosal damage in rats. Methods. MOE was prepared by reflux extraction with 70% ethanol, and its main compounds were analyzed by UPLC-Q-Exactive Orbitrap-MS. DPPH, ABTS, and FRAP methods were used to evaluate the antioxidant capacity of MOE in vitro. The gastroprotective effects of MOE were evaluated by the area of gastric injury, H&E (hematoxylin-eosin), and PAS (periodic acid-Schiff). The mechanism was explored by measuring the levels of cytokines and protein in the NF-κB signaling pathway. Results. 30 compounds were identified from MOE, mainly including lignans and alkaloids. MOE presented a high antioxidant activity in several oxidant in vitro systems. Gastric ulcer index and histological examination showed that MOE reduced ethanol-induced gastric mucosal injury in a dose-dependent manner. MOE pretreatment significantly restored the depleted activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) enzymes, reduced malondialdehyde (MDA), and prostaglandin E2 (PGE2) levels in the gastric tissue in rats. In addition, MOE also inhibited the activation of nuclear factor kappa B (NF-κB) pathway and decreased the production of proinflammatory cytokines. Conclusions. The gastroprotective effect of MOE was attributed to the inhibition of oxidative stress and the NF-κB inflammatory pathway. The results provided substantial evidence that MOE could be a promising phytomedicine for gastric ulcer prevention.

Ambient Particulate Matter Induces Vascular Smooth Muscle Cell Phenotypic Changes via NOX1/ROS/NF-κB Dependent and Independent Pathways: Protective Effects of Polyphenols

Epidemiological studies have demonstrated an association between ambient particulate matter (PM) exposure and vascular diseases. Here, we observed that treatment with ambient PM increased cell migration ability in vascular smooth muscle cells (VSMCs) and pulmonary arterial SMCs (PASMCs). These results suggest that VSMCs and PASMCs transitioned from a differentiated to a synthetic phenotype after PM exposure. Furthermore, treatment with PM increased intracellular reactive oxygen species (ROS), activated the NF-κB signaling pathway, and increased the expression of proinflammatory cytokines in VSMCs. Using specific inhibitors, we demonstrated that PM increased the migration ability of VSMCs via the nicotinamide–adenine dinucleotide phosphate (NADPH) oxidase 1 (NOX1)/ROS-dependent NF-κB signaling pathway, which also partially involved in the induction of proinflammatory cytokines. Finally, we investigated whether nature polyphenolic compounds prevent PM-induced migration and proinflammatory cytokines secretion in VSMCs. Curcumin, resveratrol, and gallic acid prevented PM_2.5-induced migration via the ROS-dependent NF-κB signaling pathway. However, honokiol did not prevent PM_2.5-induced migration or activation of the ROS-dependent NF-κB signaling pathway. On the other hand, all polyphenols prevented PM_2.5-induced cytokines secretion. These data indicated that polyphenols prevented PM-induced migration and cytokine secretion via blocking the ROS-dependent NF-κB signaling pathway in VSMCs. However, other mechanisms may also contribute to PM-induced cytokine secretion.

Topical delivery of curcumin-loaded transfersomes gel ameliorated rheumatoid arthritis by inhibiting NF-κβ pathway

Aim: To fabricate and evaluate curcumin-loaded transfersomes (Cur-TF) for the targeted delivery and enhanced therapeutic efficacy of curcumin for the treatment of rheumatoid arthritis (RA). Methods: Modified thin-film hydration method was used to prepare Cur-TF which were then embedded into carbopol-934 gel. They were further evaluated through in vitro techniques and in an in vivo arthritis model. Results: Cur-TF had optimal particle size, spherical morphology, high encapsulation efficiency and sustained drug release profiles. The Cur-TF gel had better in vitro skin penetration than plain curcumin. In vivo findings demonstrated improved clinical, histological and x-ray scores and reduced pro-inflammatory cytokines through NF-κβ inhibition. Conclusion: Cur-TF gel delivered curcumin to the arthritic dermal tissue through a topical route and demonstrated promising therapeutic efficacy by significantly alleviating complete Freud's adjuvant (CFA)-induced arthritis.

The therapeutic potential of Nrf2 inducers in chronic pain: Evidence from preclinical studies

Chronic pain remains an enormous health problem affecting approximatively 30% of the world's population. Opioids as the first line analgesics often leads to undesirable side effects when used long term. Therefore, novel therapeutic targets are urgently needed to the development of more efficacious analgesics. Substantial evidence indicates that excessive reactive oxygen species (ROS) are extremely important to the development of chronic pain. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a master transcription factor regulating endogenous antioxidant defense. Emerging evidence suggests that Nrf2 and its downstream effectors are implicated in chronic inflammatory and neuropathic pain. Notably, controversial results have been reported regarding the expression of Nrf2 and its downstream targets in peripheral and central regions involved in pain transmission. However, our recent studies and results from other laboratories demonstrate that Nrf2 inducers exert potent analgesic effects in various murine models of chronic pain. In this review, we summarized and discussed the preclinical evidence demonstrating the therapeutic potential of Nrf2 inducers in chronic pain. These evidence indicates that Nrf2 activation are beneficial in chronic pain mostly by alleviating ROS-associated pathological processes. Overall, Nrf2-based therapy for chronic pain is an area with great promise, but more research regarding its detailed mechanisms is warranted.

Aromatic and Aliphatic Apiuronides from the Bark of Cinnamomum cassia

Cinnamomum cassia Presl (Cinnamon) has been widely cultivated in the tropical or subtropical areas, such as Yunnan, Fujian, Guandong, and Hainan in China, as well as India, Vietnam, Thailand, and Malaysia. Four new glycosides bearing apiuronic acid (1, 4, 6, and 7) and their sodium or potassium salts (2, 3, and 5), together with 31 known compounds, were isolated from a hot water extract of the bark of C. cassia via repeated chromatography. The structures of the new compounds (1-7) were determined by NMR, IR, MS, and ICP-AES data and by acid hydrolysis and sugar analysis. This is the first report of the presence of apiuronic acid glycosides. Some of the isolates were evaluated for their analgesic effects on a neuropathic pain animal model induced by paclitaxel. Cinnzeylanol (8), cinnacaside (9), kelampayoside A (10), and syringaresinol (11) showed analgesic effects against paclitaxel-induced cold allodynia.

Prostaglandin 15d-PGJ2 targets PPARγ and opioid receptors to prevent muscle hyperalgesia in rats

Pharmacological agents directed to either opioid receptors or peroxisome proliferator-activated receptor gamma (PPARγ) at peripheral tissues reduce behavioral signs of persistent pain. Both receptors are expressed in muscle tissue, but the contribution of PPARγ activation to muscle pain and its modulation by opioid receptors remains unknown. To address this question, we first tested whether the endogenous PPARγ ligand 15d-PGJ2 would decrease mechanical hyperalgesia induced by carrageenan administration into the gastrocnemius muscle of rats. Next, we used receptor antagonists to determine whether the antihyperalgesic effect of 15-deoxyΔ-12,14-prostaglandin J2 (15d-PGJ2) was PPARγ- or opioid receptor-dependent. Three hours after carrageenan, muscle hyperalgesia was quantified with the Randall-Selitto test. 15d-PGJ2 prevented carrageenan-induced muscle hyperalgesia in a dose-dependent manner. The antihyperalgesic effect of 15d-PGJ2 was dose-dependently inhibited by either the PPARγ antagonist, 2-chloro-5-nitro-N-phenylbenzamide, or by the opioid receptor antagonist, naloxone. We conclude that 15d-PGJ2 targets PPARγ and opioid receptors to prevent muscle hyperalgesia. We suggest that local PPARγ receptors are important pharmacological targets for inflammatory muscle pain.

7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z Notonipetranone Attenuates Neuropathic Pain by Suppressing Oxidative Stress, Inflammatory and Pro-Apoptotic Protein Expressions

7β-(3-Ethyl-cis-crotonoyloxy)-1α-(2-methylbutyryloxy)-3,14-dehydro-Z-notonipetranone (ECN), a sesquiterpenoid obtained from a natural source has proved to be effective in minimizing various side effects associated with opioids and nonsteroidal anti-inflammatory drugs. The current study focused on investigating the effects of ECN on neuropathic pain induced by partial sciatic nerve ligation (PSNL) by mainly focusing on oxidative stress, inflammatory and apoptotic proteins expression in mice. ECN (1 and 10 mg/kg, i.p.), was administered once daily for 11 days, starting from the third day after surgery. ECN post-treatment was found to reduce hyperalgesia and allodynia in a dose-dependent manner. ECN remarkably reversed the histopathological abnormalities associated with oxidative stress, apoptosis and inflammation. Furthermore, ECN prevented the suppression of antioxidants (glutathione, glutathione-S-transferase, catalase, superoxide dismutase, NF-E2-related factor-2 (Nrf2), hemeoxygenase-1 and NAD(P)H: quinone oxidoreductase) by PSNL. Moreover, pro-inflammatory cytokines (tumor necrotic factor-alpha, interleukin 1 beta, interleukin 6, cyclooxygenase-2 and inducible nitric oxide synthase) expression was reduced by ECN administration. Treatment with ECN was successful in reducing the caspase-3 level consistent with the observed modulation of pro-apoptotic proteins. Additionally, ECN showed a protective effect on the lipid content of myelin sheath as evident from FTIR spectroscopy which showed the shift of lipid component bands to higher values. Thus, the anti-neuropathic potential of ECN might be due to the inhibition of oxidative stress, inflammatory mediators and pro-apoptotic proteins.

Attenuation of LPS-induced acute lung injury by continentalic acid in rodents through inhibition of inflammatory mediators correlates with increased Nrf2 protein expression

Background

Acute lung injury (ALI) together with acute respiratory distress syndrome (ARDS) are associated with high rate of mortality and morbidity in patients. In the current study, the anti-inflammatory effects of continentalic acid (CNT) in LPS-induced acute lung injury model was explored.

Methods

The acute lung injury model was established by administering LPS (5 mg/kg) intraperitonealy. Following LPS administration, the survival rate, temperature changes and lung Wet/Dry ratio were assessed. The antioxidants (GSH, GST, Catalase and SOD) and oxidative stress markers (MDA, NO, MPO) were evaluated in all the treated groups. Similarly, the cytokines such as IL-1β, IL-6 and TNF-α were analyzed using ELISA assay. The histological changes were determined using H and E staining, while Nrf2 and iNOS level were determined using immunohistochemistry analysis. The molecular docking analysis was performed to assess the pharmacokinetics parameters and interaction of the CNT with various protein targets.

Results

The results showed that CNT dose dependently (10, 50 and 100 mg/kg) reduced mortality rate, body temperature and lungs Wet/Dry ratio. CNT post-treatment significantly inhibited LPS-induced production of pro-inflammatory cytokines such as IL-1β, IL-6 and TNF-α. The CNT post-treatment markedly improved the hematological parameters, while significantly reduced the MPO (indicator of the neutrophilic infiltration) activity compared to the LPS treated group. Furthermore, the CNT (100 mg/kg) post-administration remarkably inhibited the lung Wet/Dry ratio. The CNT (100 mg/kg) treated group showed marked reduction in the oxidative stress markers such as malonaldehyde (MDA) and Nitric oxide (NO) concentration, while induced the level of the anti-oxidant enzymes such as GST, GSH, Catalase and SOD. Similarly, the CNT markedly reduced the iNOS expression level, while induced the Nrf2 protein expression. Additionally, the molecular docking study showed significant binding interaction with the Nrf2, p65, Keap1, HO-1, IL-1β, IL-6, TNF-α and COX-2, while exhibited excellent physicochemical properties.

Conclusion

The CNT showed marked protection against the LPS-induced lung injury and improved the behavioral, biochemical and histological parameters. Furthermore, the CNT showed significant interaction with several protein targets and exhibited better physicochemical properties.

Attenuation of Spatial Memory in 5xFAD Mice by Halting Cholinesterases, Oxidative Stress and Neuroinflammation Using a Cyclopentanone Derivative

Alzheimer's disease (AD) is an irreversible and chronic neurological disorder that gradually destroys memory and thinking skills. The research study was designed to investigate the underlying molecular signaling involved in the neuroprotective effects of cyclopentanone derivative i.e., 2-(hydroxyl-(3-nitrophenyl)methyl)cyclopentanone (3NCP) as a therapeutic agent for AD. In this study, In vivo studies were carried out on a well-known 5xFAD mice model using different behavioural test models such as open field, rotarod, Morris water maze (MWM), and Y-maze tests. Furthermore, in vitro cholinesterase inhibition activity assays were carried out. The frontal cortex (FC) and hippocampus (HC) homogenates were tested for the levels/activities of cholinesterases, glutathione (GSH), glutathione S-transferase (GST), and catalase. Furthermore, the hippocampal expression of inflammatory cytokines was observed via RT-PCR and western blot. The results of in vivo studies show an enhancement in the learning behavior. The 3NCP treatment reduced latency time in MWM and Y-maze tests, also increase spontaneous alternation indicate significant effect of 3NCP on memory. Furthermore, open field and rotarod studies revealed that 3NCP does not cause motor coordination deficit. The results of the in vitro studies revealed that the IC50 values of the 3NCP against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were 16.17 and 20.51 µg/mL, respectively. This decline in AChE and BChE was further supported by ex vivo studies. Further, the 3NCP mitigates the GSH level, GST, and catalase activities in HC and FC. The mRNA and protein expression of inflammatory cytokines (IL-1β, IL-6, TNF-α) markedly declined in RT-PCR and western blotting. The results of the current study conclusively demonstrate that 3NCP reduces oxidative stress and mitigates neuroinflammation in 5xFAD mice, implying that 3NCP may be a potential therapeutic candidate for AD treatment in the future.

Anti-inflammatory and antinociceptive activity profile of a new lead compound - LQFM219

LQFM219 is a molecule designed from celecoxibe (COX-2 inhibitor) and darbufelone (inhibitor of COX-2 and 5-LOX) lead compounds through a molecular hybridisation strategy. Therefore, this work aimed to investigate the antinociceptive and anti-inflammatory activities of this new hybrid compound. The acute oral systemic toxicity of LQFM219 was evaluated via the neutral red uptake assay. Acetic acid-induced abdominal writhing and CFA-induced mechanical hyperalgesia were performed to evaluate the antinociceptive activity, and the anti-oedematogenic activity was studied by CFA-induced paw oedema and croton oil-induced ear oedema. Moreover, the acute anti-inflammatory activity was determined by carrageenan-induced pleurisy. In addition, cell migration, myeloperoxidase enzyme activity, and TNF-α and IL-1β levels were determined in pleural exudate. Moreover, a redox assay was conducted using electroanalytical and DPPH methods. The results demonstrated that LQFM219 was classified as GHS category 4, and it showed better free radical scavenger activity compared to BHT. Besides, LQFM219 decreased the number of writhings induced by acetic acid and the response to the mechanical stimulus in the CFA-induced mechanical hyperalgesia test. Furthermore, LQFM219 reduced oedema formation, cell migration, and IL-1β and TNF-α levels in the pleural cavity and inhibited myeloperoxidase enzyme activity. Thus, our study provides that the new pyrazole derivative, LQFM219, demonstrated low toxicity, antinociceptive and anti-inflammatory potential in vitro and in vivo.

3D-Printed Extracellular Matrix/Polyethylene Glycol Diacrylate Hydrogel Incorporating the Anti-inflammatory Phytomolecule Honokiol for Regeneration of Osteochondral Defects

BACKGROUND

Osteoarthritis is the leading cause of disability worldwide; cartilage degeneration and defects are the central features. Significant progress in tissue engineering holds promise to regenerate damaged cartilage tissue. However, a formidable challenge is to develop a 3-dimensional (3D) tissue construct that can regulate local immune environment to facilitate the intrinsic osteochondral regeneration.

PURPOSE

To evaluate efficacy of a 3D-printed decellularized cartilage extracellular matrix (ECM) and polyethylene glycol diacrylate (PEGDA) integrated novel scaffold (PEGDA/ECM) together with the natural compound honokiol (Hon) for regenerating osteochondral defect.

STUDY DESIGN

Controlled laboratory study.

METHODS

We used a stereolithography-based 3D printer for PEGDA/ECM bioprinting. A total of 36 Sprague-Dawley rats with cylindrical osteochondral defect in the trochlear groove of the femur were randomly assigned into 3 different treatments: no scaffold implantation (Defect group), 3D printed PEGDA/ECM scaffold alone (PEGDA/ECM group), or Hon suspended in a 3D-printed PEGDA/ECM scaffold (PEGDA/ECM/Hon group). 12 rats that underwent only medial parapatellar incision surgery were used as normal controls. The femur specimens were postoperatively harvested at 4 and 8 weeks for gross, micro-CT, and histological evaluations. The efficacy of PEGDA/ECM/Hon scaffold on the release of proinflammatory cytokines from the macrophages stimulated by lipopolysaccharide (LPS) was evaluated in-vitro.

RESULTS

In vitro results determined that PEGDA/ECM/Hon scaffold could suppress the release of proinflammatory cytokines from macrophages that were stimulated by LPS. Macroscopic images showed that the PEGDA/ECM/Hon group had significantly higher ICRS scoring than that of defect and PEGDA/ECM groups. Micro-CT evaluation demonstrated that much more bony tissue was formed in the defect sites implanted with the PEGDA/ECM scaffold or PEGDA/ECM/Hon scaffold compared with the untreated defects. Histological analysis showed that the PEGDA/ECM/Hon group had a significant enhancement in osteochondral regeneration at 4 and 8 weeks after surgery in comparison with the ECM/PEGDA or defect group.

CONCLUSION

This study demonstrated that 3D printing of PEGDA/ECM hydrogel incorporating the anti-inflammatory phytomolecule honokiol could provide a promising scaffold for osteochondral defect repair.

The newly synthesized compounds (NCHDH and NTHDH) attenuates LPS-induced septicemia and multi-organ failure via Nrf2/HO1 and HSP/TRVP1 signaling in mice

The sepsis is considered as serious clinic-pathological condition related with high rate of morbidity and mortality in critical care settings. In the proposed study, the hydrazides derivatives N-(benzylidene)-2-((2-hydroxynaphthalen-1-yl)diazenyl)benzohydrazides (1-2) (NCHDH and NTHDH) were investigated against the LPS-induced sepsis in rodents. The NCHDH and NTHDH markedly improved the physiological sign and symptoms associated with the sepsis such as mortality, temperature, and clinical scoring compared to negative control group, which received only LPS (i.p.). The NCHDH and NTHDH also inhibited the production of the NO and MPO compared to the negative control. Furthermore, the treatment control improved the histological changes markedly of all the vital organs. Additionally, the Masson's trichrome and PAS (Periodic Acid Schiff) staining also showed improvement in the NCHDH and NTHDH treated group in contrast to LPS-induced group. The antioxidants were enhanced by the intervention of the NCHDH and NTHDH and the level of the MDA and POD were attenuated marginally compared to the LPS-induced group. The hematology study showed marked improvement and the reversal of the LPS-induced changes in blood composition compared to the negative control. The synthetic function of the liver and kidney were preserved in the NCHDH and NTHDH treated group compared to the LPS-induced group. The NCHDH and NTHDH markedly enhanced the Nrf2, HO-1 (Heme oxygenase-1), while attenuated the Keap1 and TRPV1 expression level as compared to LPS treated group. Furthermore, the NCHDH and NTHDH treatment showed marked increased in the mRNA expression level of the HSP70/90 proteins compared to the negative control.

Matrine alleviates neurobehavioral alterations via modulation of JNK-mediated caspase-3 and BDNF/VEGF signaling in a mouse model of burn injury

RATIONALE

The c-Jun N-terminal kinase (JNK) pathway and neurotrophic factor dysregulation play a critical role in the pathogenesis of neurobehavioral disorders (anxiety and depression). Targeting the JNK pathway and BDNF/VEGF signaling may signify a new avenue for the treatment of neurobehavioral disorders.

OBJECTIVES

The present study investigated the effect of matrine (Mat) against anxiety- and depressive-like emotional status in an acute mouse model of burn injury and explores its underlying mechanism.

METHODS

In the mouse model of thermal injury, anxiety- and depression-related behaviors were evaluated using the elevated plus-maze test, the light-dark box test, the open-field test, the forced swimming test, and the tail suspension test. The JNK/caspase-3 and BDNF/VEGF proteins were determined by immunohistochemistry. Additionally, proinflammatory cytokine, antioxidant, nitric oxide, and corticosterone levels were also measured.

RESULTS

The results showed that treatment with Mat significantly improves anxiety- and depressive-like behaviors. It remarkably reduced the levels of proinflammatory cytokines, malondialdehyde, and nitric oxide in the hippocampus and prefrontal cortex of a mouse brain. It considerably improved burn-induced alteration in the antioxidant status, corticosterone, and BDNF/VEGF. It also inhibited burn-induced apoptotic signaling by downregulating the expression of JNK/caspase-3. Similarly, it prevented DNA damage and histopathological changes in the dentate gyrus of the hippocampus. Furthermore, molecular docking results showed that Mat possess better binding affinity for JNK/caspase-3 and BDNF/VEGF proteins.

CONCLUSIONS

These findings provide convincing evidence that Mat improves anxiety- and depressive-like emotional status through modulation of JNK-mediated inflammatory, oxidative stress, apoptotic, and BDNF/VEGF signaling in an acute mouse model of burn injury.

Effectiveness in the Block by Honokiol, a Dimerized Allylphenol from Magnolia Officinalis, of Hyperpolarization-Activated Cation Current and Delayed-Rectifier K+ Current

Background: Honokiol (HNK), a dimer of allylphenol obtained from the bark of Magnolia officinalis was demonstrated to exert an array of biological actions in different excitable cell types. However, whether or how this compound can lead to any perturbations on surface-membrane ionic currents remains largely unknown. Methods: We used the patch clamp method and found that addition of HNK effectively depressed the density of macroscopic hyperpolarization-activated cation currents (I_h) in pituitary GH₃ cells in a concentration-, time- and voltage-dependent manner. By the use of a two-step voltage protocol, the presence of HNK (10 μM) shifted the steady-state activation curve of I_h density along the voltage axis to a more negative potential by approximately 11 mV, together with no noteworthy modification in the gating charge of the current. Results: The voltage-dependent hysteresis of I_h density elicited by long-lasting triangular ramp pulse was attenuated by the presence of HNK. The HNK addition also diminished the magnitude of deactivating I_h density elicited by ramp-up depolarization with varying durations. The effective half-maximal concentration (IC₅₀) value needed to inhibit the density of I_h or delayed rectifier K⁺ current identified in GH₃ cells was estimated to be 2.1 or 6.8 μM, respectively. In cell-attached current recordings, HNK decreased the frequency of spontaneous action currents. In Rolf B1.T olfactory sensory neurons, HNK was also observed to decrease I_h density in a concentration-dependent manner. Conclusions: The present study highlights the evidence revealing that HNK has the propensity to perturb these ionic currents and that the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel is proposed to be a potential target for the in vivo actions of HNK and its structurally similar compounds.

Anti-epileptic activity of daidzin in PTZ-induced mice model by targeting oxidative stress and BDNF/VEGF signaling

Epilepsy is a complex and multifactorial neurodegenerative disease described by recurrent seizures. Oxidative stress and dysregulation of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) are critical factors for the development of epilepsy. Daidzin is well-known for its effective anti-inflammatory and antioxidant potential for centuries. The present study was focused on exploring the anti-epileptic potential of daidzin in the pentylenetetrazole-induced mice model. Daidzin (1, 5, and 10 mg/kg) was administered in the acute study and the dose was optimized. Pretreatment with daidzin remarkably reduced the severity of epileptogenesis in a dose-dependent manner. Moreover, chronic epilepsy was induced in mice by administration of PTZ (35 mg/kg, i.p) every alternative day for 21 days. Results demonstrated that daidzin significantly prevented epileptogenesis and reversed histopathological changes in the hippocampus. It remarkably improved antioxidant (glutathione, glutathione sulfotransferase, superoxide dismutase, and catalase) levels while decreased MDA (malondialdehyde) and nitrite production in the brain. It remarkably improved the expressions of heme oxygenase-1 (HO-1) and BDNF while reduced the expression of VEGF. It remarkably prevented the neuronal apoptosis in the brain tissue. Additionally, spectroscopic analysis such as FTIR (Fourier transform infrared spectroscopy) and DSC (differential scanning calorimetry) revealed that daidzin remarkably prevented PTZ-induced protein damage. HPLC-UV spectrophotometry results demonstrated that there was no peak of aglycone daidzin (metabolite) in the brain sample which specify that the anticonvulsant effect of the compound is due to its direct entry into the brain tissue. Moreover, the molecular docking results showed that daidzin possesses a better binding affinity for ALDH2, estrogen receptor-β, P13k, AKT2, mTORC1, and HIF-1-α proteins. Taken together, the results of the present study showed that daidzin has remarkable neuroprotective and anti-epileptic properties through modulation of oxidative stress, BDNF/VEGF, and apoptotic signaling in the brain tissue of PTZ-kindled mice.