Intrathecal administration of naringenin improves motor dysfunction and neuropathic pain following compression spinal cord injury in rats: relevance to its antioxidant and anti-inflammatory activities

Rutin-loaded chitosan nanoparticles alleviated Freund's adjuvant induced rheumatoid arthritis via modulating oxidative stress and inflammatory parameters in Wistar rats

Rheumatoid arthritis (RA) is the most common chronic inflammatory disease, primarily affecting the joints and with stromal tissue dysregulation causing chronic inflammation and joint destruction. Rutin is a natural flavonoid with potential therapeutic properties in chronic destructive conditions including rheumatoid diseases. In this study, the protective effects of rutin nanoformulation in an animal model of rheumatoid arthritis caused by Freund's complete adjuvant (FCA) were investigated. Sixty male rats were randomly divided into ten groups including normal, negative control, prednisolone 10 mg/kg (positive control), 3 doses of rutin (15, 30, 45mg/kg), rutin nanoparticles (15, 30, 45 mg/kg), and nanoparticle without rutin, for 28 days. Different behavioral parameters including the open field test, acetone drop test, hot plate test, Von Frey test, and inclined plane test were evaluated. Serum levels of glutathione (GSH), catalase, and nitric oxide as well as histopathological analyses were measured in different groups. Also, matrix metalloproteinase (MMP)-2 and MMP-9 activity were appraised by gelatin zymography. The injection of FCA prolonged the rats' immobility duration in comparison to the control group. Rheumatoid arthritis induction also increased nitric oxide and decreased GSH and catalase levels, while these effects were reversed in the groups that received nanoparticles containing rutin and prednisolone. Rutin nanoparticles suppressed MMP-9 and activated MMP-2. Also, this rutin drug delivery system plays a significant role in the improvement of histopathological symptoms. Considering the improvement of behavioral and tissue symptoms and the modulation of the level of inflammatory cytokines, nanoparticles containing rutin can be proposed as a suitable approach in the management of patients with rheumatoid arthritis.

Protective effect of a hydromethanolic extract from Fraxinus excelsior L. bark against a rat model of aluminum chloride-induced Alzheimer's disease: Relevance to its anti-inflammatory and antioxidant effects

ETHNOPHARMACOLOGICAL RELEVANCE

Fraxinus excelsior L. (FE), commonly known as the ash, belongs to the Oleaceae family and has shown several pharmacological and biological properties, such as antioxidant, immunomodulatory, neuroprotective, and anti-inflammatory effects. It has also attracted the most attention toward neuroinflammation. Moreover, FE bark and leaves have been used to treat neurological disorders, aging, neuropathic pain, urinary complaints, and articular pain in traditional and ethnomedicine. Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder resulting from the involvement of amyloid-beta, metal-induced oxidative stress, and neuroinflammation.

AIM OF THE STUDY

The objective of the current study was to assess the neuroprotective effects of hydromethanolic extract from FE bark in an AlCl3-induced rat model of AD.

MATERIALS AND METHODS

The maceration process was utilized to prepare the hydromethanolic extract of FE bark, and characterized by LC-MS/MS. To assess the anti-AD effects of the FE extract, rats were categorized into five different groups, AlCl3; normal control; FE-treated groups at 50, 100, and 200 mg/kg. Passive avoidance learning test, Y-maze, open field, and elevated plus maze behavioral tests were evaluated on days 7 and 14 to analyze the cognitive impairments. Zymography analysis, biochemical tests, and histopathological changes were also followed in different groups.

RESULTS

LC-MS/MS analysis indicated the presence of coumarins, including isofraxidin7-O-diglucoside in the methanolic extract of FE as a new isofraxidin derivative in this genus. FE significantly improved memory and cognitive function, maintained weight, prevented neuronal damages, and preserved the hippocampus's histological features, as demonstrated by behavioral tests and histopathological analysis. FE increased anti-inflammatory MMP-2 activity, whereas it decreased that of inflammatory MMP-9. Moreover, FE increased plasma antioxidant capacity by enhancing CAT and GSH while decreasing nitrite levels in the serum of treated groups. In comparison between the treated groups, the rats that received high doses of the FE extract (200 mg/kg) showed the highest therapeutic effect.

CONCLUSION

FE rich in coumarins could be an effective anti-AD adjunct agent, passing through antioxidant and anti-inflammatory pathways. These results encourage further studies for the development of this extract as a promising agent in preventing, managing, or treating AD and related diseases.

Matrix metalloproteinases as attractive therapeutic targets for chronic pain: A narrative review

Chronic pain constitutes an abnormal pain state that detrimentally affects the quality of life, daily activities, occupational performance, and stability of mood. Despite the prevalence of chronic pain, effective drugs with potent abirritation and minimal side effects remain elusive. Substantial studies have revealed aberrant activation of the matrix metalloproteinases (MMPs) in multiple chronic pain models. Additionally, emerging evidence has demonstrated that the downregulation of MMPs can alleviate chronic pain in diverse animal models, underscoring the unique and crucial role of MMPs in different stages and types of chronic pain. This review delves into the mechanistic insights and roles of MMPs in modulating chronic pain. The aberrant activation of MMPs has been linked to neuropathic pain through mechanisms involving myelin abnormalities in peripheral nerve and spinal dorsal horn (SDH), hyperexcitability of dorsal root ganglion (DRG) neurons, activation of N-methyl-d-aspartate receptors (NMDAR) and Ca2+-dependent signals, glial cell activation, and proinflammatory cytokines release. Different MMPs also contribute significantly to inflammatory pain and cancer pain. Furthermore, we summarized the substantial therapeutic potential of MMP pharmacological inhibitors across different types of chronic pain. Overall, our findings underscore the promising therapeutic prospects of MMPs targeting for managing chronic pain.

Propofol Ameliorates Spinal Cord Injury Process by Mediating miR-672-3p/TNIP2 Axis

Propofol has been found to have a protective effect against spinal cord injury (SCI). However, the underlying molecular mechanism of propofol regulating SCI process remains unclear. In this study, lipopolysaccharide (LPS)-induced PC12 cells were used to build SCI cell models. Cell viability and apoptosis were determined by cell counting kit 8 assay, flow cytometry, and caspase-3 activity detection. The protein levels of apoptosis-related markers and TNFAIP3 interacting protein 2 (TNIP2) were assessed using western blot analysis, and the levels of inflammatory factors were detected using ELISA. Cell oxidative stress was evaluated by measuring malondialdehyde (MDA) and reactive oxygen species (ROS) levels. The expression of microRNA (miR)-672-3p was examined by quantitative real-time PCR. SCI rat models were constructed to assess the effect of propofol in vivo. We found that propofol treatment promoted viability, while inhibited apoptosis, inflammation and oxidative stress of LPS-induced PC12 cells. Propofol decreased miR-672-3p expression, and miR-672-3p overexpression eliminated the inhibiting effect of propofol on LPS-induced PC12 cell injury. Besides, miR-672-3p targeted TNIP2, and TNIP2 knockdown reversed the protective effect of miR-672-3p inhibitor or propofol against LPS-induced PC12 cell injury. In vivo experiments, propofol treatment enhanced the motor function recovery and inhibited apoptosis of SCI rat models. In conclusion, propofol increased TNIP2 level by reducing miR-672-3p expression, thereby alleviating LPS-induced PC12 cell injury and improving the motor function of SCI rat models.

Shaoyao Gancao decoction alleviates the central hyperalgesia of recurrent NTG-induced migraine in rats by regulating the NGF/TRPV1/COX-2 signal pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Shaoyao Gancao Decoction (SGD) is well known as an effective prescription for analgesia composed of two herbs, and is noted as traditional Chinese medicine morphine. It is widely used in various conditions causing pain, including migraine. However, there is currently no research exploring the mechanism of action in the treatment of migraines.

AIM OF THE STUDY

The current research was devised to determine the underlying regulatory mechanism of SGD, by verifying its role in the NGF/TRPV1/COX-2 signal pathway.

MATERIALS AND METHODS

The active components in SGD were identified by UHPLC-MS. A migraine model was prepared by subcutaneous (s.c.) injection of nitroglycerin (NTG) into the neck to detect migraine-like behavior, orbital hyperalgesia threshold changes, and the therapeutic effect of SGD. The mechanism of SGD in remedying migraine was studied through transcriptome sequencing (RNA-seq), which was further validated utilizing Elisa, Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB) experiments.

RESULTS

In the SGD chemical composition analysis, 45 components were identified including gallic acid, paeoniflorin and albiforin. In the behavioral experiments, SGD treatment significantly decreased the score of migraine-like head scratching in the NTG-induced migraine model (Mod) rats, while the hyperalgesia threshold increased outstandingly on days 10, 12, and 14 (P < 0.01, P < 0.001 or P < 0.0001). In migraine biomarkers experiment, compared with the Mod group, the 5-hydroxytryptamine (5-HT) contents were outstandingly enhanced by SGD treatment, while nitric oxide (NO) contents were markedly declined (P < 0.01). In the RNA-seq test, the down-regulated genes of SGD inhibiting hyperalgesia migraine included the neurotrophic factor (NGF) and transient receptor potential vanillic acid subfamily protein 1 receptor (TRPV1). The down-regulation pathway is the inflammatory mediator regulation of TRP channels. In gene set enrichment analysis (GSEA), SGD decreased the over-expression of protooncogene tyrosine-protein kinase Src (SRC) and TRPV1 in this pathway, and the two genes clustered at its lower end, with similar functions. PPI network results show that NGF interacts with TRPV1. Further verification shows that when compared with Mod group, the plasma cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2) protein expression levels and the dura mater calcitonin gene-related peptide (CGRP), extracellular signal-regulated kinase (ERK), p-ERK, SRC and NGF protein expression levels in the SGD group were remarkably decreased (P < 0.01, P < 0.001 or P < 0.0001), and the expression level of TRPV1 protein showed a downward trend (P = 0.06). The expression levels of COX-2, NO, CGRP, TRPV1, SRC and NGF mRNA in the dura mater was overtly down-regulated (P < 0.05, P < 0.01 or P < 0.001).

CONCLUSIONS

SGD has a significant inhibitory effect on the NGF/TRPV1/COX-2 signaling pathway that mediates central hyperalgesia migraine, thus suggesting the molecular mechanism of SGD in improving the symptoms of migraine may be related to the central hyperalgesia neurotransmitter that regulates the pathogenesis of migraine.

Mechanism of spinal cord injury regeneration and the effect of human neural stem cells-secretome treatment in rat model

BACKGROUND

Globally, complete neurological recovery of spinal cord injury (SCI) is still less than 1%, and 90% experience permanent disability. The key issue is that a pharmacological neuroprotective-neuroregenerative agent and SCI regeneration mechanism have not been found. The secretomes of stem cell are an emerging neurotrophic agent, but the effect of human neural stem cells (HNSCs) secretome on SCI is still unclear.

AIM

To investigate the regeneration mechanism of SCI and neuroprotective-neuroregenerative effects of HNSCs-secretome on subacute SCI post-laminectomy in rats.

METHODS

An experimental study was conducted with 45 Rattus norvegicus, divided into 15 normal, 15 control (10 mL physiologic saline), and 15 treatment (30 μL HNSCs-secretome, intrathecal T10, three days post-traumatic). Locomotor function was evaluated weekly by blinded evaluators. Fifty-six days post-injury, specimens were collected, and spinal cord lesion, free radical oxidative stress (F2-Isoprostanes), nuclear factor-kappa B (NF-κB), matrix metallopeptidase 9 (MMP9), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), transforming growth factor-beta (TGF-β), vascular endothelial growth factor (VEGF), B cell lymphoma-2 (Bcl-2), nestin, brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF) were analyzed. The SCI regeneration mechanism was analyzed using partial least squares structural equation modeling (PLS SEM).

RESULTS

HNSCs-secretome significantly improved locomotor recovery according to Basso, Beattie, Bresnahan (BBB) scores and increased neurogenesis (nestin, BDNF, and GDNF), neuroangiogenesis (VEGF), anti-apoptotic (Bcl-2), anti-inflammatory (IL-10 and TGF-β), but decreased pro-inflammatory (NF-κB, MMP9, TNF-α), F2-Isoprostanes, and spinal cord lesion size. The SCI regeneration mechanism is valid by analyzed outer model, inner model, and hypothesis testing in PLS SEM, started with pro-inflammation followed by anti-inflammation, anti-apoptotic, neuroangiogenesis, neurogenesis, and locomotor function.

CONCLUSION

HNSCs-secretome as a potential neuroprotective-neuroregenerative agent for the treatment of SCI and uncover the SCI regeneration mechanism.

The mechanism of human neural stem cell secretomes improves neuropathic pain and locomotor function in spinal cord injury rat models: through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities

Background

Globally, spinal cord injury (SCI) results in a big burden, including 90% suffering permanent disability, and 60%-69% experiencing neuropathic pain. The main causes are oxidative stress, inflammation, and degeneration. The efficacy of the stem cell secretome is promising, but the role of human neural stem cell (HNSC)-secretome in neuropathic pain is unclear. This study evaluated how the mechanism of HNSC-secretome improves neuropathic pain and locomotor function in SCI rat models through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

Methods

A proper experimental study investigated 15 Rattus norvegicus divided into normal, control, and treatment groups (30 μL HNSC-secretome, intrathecal in the level of T10, three days post-traumatic SCI). Twenty-eight days post-injury, specimens were collected, and matrix metalloproteinase (MMP)-9, F2-Isoprostanes, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β, and brain derived neurotrophic factor (BDNF) were analyzed. Locomotor recovery was evaluated via Basso, Beattie, and Bresnahan scores. Neuropathic pain was evaluated using the Rat Grimace Scale.

Results

The HNSC-secretome could improve locomotor recovery and neuropathic pain, decrease F2-Isoprostane (antioxidant), decrease MMP-9 and TNF-α (anti-inflammatory), as well as modulate TGF-β and BDNF (neurotrophic factor). Moreover, HNSC-secretomes maintain the extracellular matrix of SCI by reducing the matrix degradation effect of MMP-9 and increasing the collagen formation effect of TGF-β as a resistor of glial scar formation.

Conclusions

The present study demonstrated the mechanism of HNSC-secretome in improving neuropathic pain and locomotor function in SCI through antioxidant, anti-inflammatory, anti-matrix degradation, and neurotrophic activities.

Naringin and Naringenin Polyphenols in Neurological Diseases: Understandings from a Therapeutic Viewpoint

The glycosides of two flavonoids, naringin and naringenin, are found in various citrus fruits, bergamots, tomatoes, and other fruits. These phytochemicals are associated with multiple biological functions, including neuroprotective, antioxidant, anticancer, antiviral, antibacterial, anti-inflammatory, antiadipogenic, and cardioprotective effects. The higher glutathione/oxidized glutathione ratio in 3-NP-induced rats is attributed to the ability of naringin to reduce hydroxyl radical, hydroperoxide, and nitrite. However, although progress has been made in treating these diseases, there are still global concerns about how to obtain a solution. Thus, natural compounds can provide a promising strategy for treating many neurological conditions. Possible therapeutics for neurodegenerative disorders include naringin and naringenin polyphenols. New experimental evidence shows that these polyphenols exert a wide range of pharmacological activity; particular attention was paid to neurodegenerative diseases such as Alzheimer's and Parkinson's diseases, as well as other neurological conditions such as anxiety, depression, schizophrenia, and chronic hyperglycemic peripheral neuropathy. Several preliminary investigations have shown promising evidence of neuroprotection. The main objective of this review was to reflect on developments in understanding the molecular mechanisms underlying the development of naringin and naringenin as potential neuroprotective medications. Furthermore, the configuration relationships between naringin and naringenin are discussed, as well as their plant sources and extraction methods.

Quercetin Derivatives in Combating Spinal Cord Injury: A Mechanistic and Systematic Review

Spinal cord injury (SCI) possesses a complicated etiology. There is no FDA-approved treatment for SCI, and the majority of current interventions focus on reducing symptoms. During SCI, inflammation, oxidative stress, apoptosis, and autophagy are behind the secondary phase of SCI and cause serious consequences. It urges the need for providing multi-targeting agents, that possess lower side effects and higher efficacy. The plant secondary metabolites are multi-targeting agents and seem to provide new roads in combating diseases. Flavonoids are phytochemicals of continual interest to scientists in combating neurodegenerative diseases (NDDs). Flavonoids are being studied for their biological and pharmacological effects, particularly as antioxidants, anti-inflammatory agents, anti-apoptotic, and autophagy regulators. Quercetin is one of the most well-known flavonols known for its preventative and therapeutic properties. It is a naturally occurring bioactive flavonoid that has recently received a lot of attention for its beneficial effects on NDDs. Several preclinical evidence demonstrated its neuroprotective effects. In this systematic review, we aimed at providing the biological activities of quercetin and related derivatives against SCI. Detailed neuroprotective mechanisms of quercetin derivatives are also highlighted in combating SCI.