Thymus algeriensis and Thymus fontanesii exert neuroprotective effect against chronic constriction injury-induced neuropathic pain in rats

Natural products modulating MAPK for CRC treatment: a promising strategy

Colorectal cancer (CRC) is a common malignant tumor of the digestive system, and the pathogenic mechanism is still unclear, mostly related to genetics, immunity, inflammation, and abnormal activation of tumor-related signaling pathways. MAPK belongs to the Ser/Thr kinase family, which plays an important role in complex cellular programs such as the regulation of cell proliferation, differentiation, apoptosis, angiogenesis, and tumor metastasis. Increasing evidence supports that MAPK activation is highly correlated with the risk of CRC. Targeting MAPK may be a therapeutic strategy, and natural products show great therapeutic potential in regulating MAPK-related proteins. In this paper, we searched PubMed, Web of Science and CNKI databases with keywords "colorectal cancer, natural products, MAPK pathway, ERK, P38, JNK" for relevant studies in the last 14 years from 2010 to 2024. This work retrieved 47 studies, aiming to provide new therapeutic strategies for CRC patients and lay the foundation for new drug development.

Vitamin D3 Exerts a Neuroprotective Effect in Metabolic Syndrome Rats: Role of BDNF/TRKB/Akt/GS3Kβ Pathway

Metabolic syndrome (MetS) is usually associated with cognitive impairment, neuropathic pain, and reduced brain-derived neurotrophic factor (BDNF) levels. BDNF via tropomyosin receptor kinase B (TrkB) exerts neuroprotection by activating protein kinase B (Akt) to inhibit glycogen synthase kinase-3β (GSK3β). Although Vitamin D3 (VitD3) has demonstrated favorable metabolic and neuronal outcomes in MetS, the precise molecular mechanisms underlying its neuroprotective effects remain poorly elucidated. We aimed to test the hypothesis that VitD3 mitigates MetS-induced cognition deficits and neuropathic pain via modulating the BDNF/TRKB/Akt/GS3Kβ signaling pathway. MetS was induced in male rats by 10% fructose-supplemented water and 3% salt-enriched diet. After 6 weeks, normal and MetS rats received either vehicle or VitD3 (10 µg/kg/day) for an additional 6 weeks. Glycemic status, lipid profile, and behavioral changes were assessed. The advanced glycation end products (AGEs), and markers of inflammation (TNF-α and NF-κB), oxidative stress (malondialdehyde), and apoptosis (caspase3), as well as BDNF, TrkB, PI3K, Akt, GSK3β, phosphorylated tau, and amyloid beta (Aβ) were assessed in the cerebral cortex. MetS rats had deteriorated glycemic and lipid profiles, higher AGEs, reduced levels of BDNF, TrkB, PI3K, and active Akt, along with increased GSK3β levels, inflammation, oxidative stress, and apoptosis. These changes were associated with higher levels of cognitive impairment markers phosphorylated tau and Aβ, as well as behavioral changes indicative of cognitive impairment and neuropathic pain. VitD3 improved the cognitive and behavioral alterations, while mitigating the associated molecular derangements. Our results indicate that VitD3 may exert neuroprotective effects by modulating the BDNF/TrkB/PI3K/Akt/GSK3β signaling pathway.

Post-treatment with maropitant reduces oxidative stress, endoplasmic reticulum stress and neuroinflammation on peripheral nerve injury in rats

OBJECTIVE

To determine the effective dose and therapeutic potential of maropitant using through expression of mediators of oxidative stress, inflammatory and of the unfolded protein response (UPR) (bio) markers on spinal cord using a model of neuropathic pain induced through chronic constriction injury (CCI) in rats.

STUDY DESIGN

Randomized, blinded, prospective experimental study.

ANIMALS

98 male Wistar rats.

METHODS

Rats were anesthetized with sevoflurane and after CCI, they were randomly assigned to the following groups that received: vehicle, 3, 6, 15, 30 e 50 mg/kg/24q of maropitant. The effect on inflammatory mediators (IL10, TNFα), oxidative stress (GPx, CAT, SOD), microglial (IBA-1) and neuronal (NeuN, TACR1) markers was evaluated though immunohistochemistry and expression levels of markers of hypoxia (HIF1α, Nrf2), antioxidant enzymes (Catalse, Sod1 and GPx1), and endoplasmic reticulum stress mediators (GRP78, CHOP and PERK) through qRT-PCR.

RESULTS

Intraperitoneal injection (IP) of maropitant inhibited nociception with ID50 values of 4,1 mg/kg (5,85-19,36) in a neuropathic pain model through CCI. A dose of 30 mg/kg/24q was significantly effective in reducing mechanical allodynia 1 to 4h after treatment with nociception inhibition (145,83%). A reduction in the expression of hypoxia factors (HIF1α, Nrf2) was observed, along with an increase in antioxidant activity (CAT, SOD and GPX). Additionally, there was a reduction in inflammatory markes (IL10, TNFα), microglial (IBA-1), and neuronal markers (NeuN, TACR1).

CONCLUSION AND CLINICAL RELEVANCE

These findings demonstrate that the determined dose, administered daily for seven days, had an antinociceptive effect, as well as anti-inflammatory and antioxidant activity.

Mitigation of sciatica injury-induced neuropathic pain through active metabolites derived from medicinal plants

Sciatica characterized by irritation, inflammation, and compression of the lower back nerve, is considered one of the most common back ailments globally. Currently, the therapeutic regimens for sciatica are experiencing a paradigm shift from the conventional pharmacological approach toward exploring potent phytochemicals from medicinal plants. There is a dire need to identify novel phytochemicals with anti-neuropathic potential. This review aimed to identify the potent phytochemicals from diverse medicinal plants capable of alleviating neuropathic pain associated with sciatica. This review describes the pathophysiology of sciatic nerve pain, its cellular mechanisms, and the pharmacological potential of various plants and phytochemicals using animal-based models of sciatic nerve injury-induced pain. Extensive searches across databases such as Medline, PubMed, Web of Science, Scopus, ScienceDirect, and Google Scholar were conducted. The findings highlights 39 families including Lamiaceae, Asteraceae, Fabaceae, and Apocyanaceae and Cucurbitaceae, effectively treating sciatic nerve injury-induced pain. Flavonoids made up 53% constituents, phenols and terpenoids made up 15%, alkaloids made up 13%, and glycosides made up 6% to be used in neuorpathic pain. Phytochemicals derived from various medicinal plants can serve as potential therapeutic targets for both acute and chronic sciatic injury-induced neuropathic pain.

Anti-Pyretic, Analgesic, and Anti-Inflammatory Activities of Meloxicam and Curcumin Co-Encapsulated PLGA Nanoparticles in Acute Experimental Models

Herein, we evaluated the in vivo effects of meloxicam and curcumin co-encapsulated PLGA nanoparticles in experimental acute models of pyrexia, nociception, and inflammation. Seven groups (n = 6) were designed for each investigation and pretreated intraperitoneally (i.p.): the control group, meloxicam (4 mg/kg b.w.), curcumin (15 mg/kg b.w.), and equivalent content containing PLGA capped nanoparticles of meloxicam (Mlx-NP) and curcumin (Cur-NP) alone and in combination (Mlx-Cur-NP; at two doses). The results showed that PLGA encapsulation significantly (p ≤ 0.05) improved the in vivo activities of each compound. Furthermore, co-encapsulation of meloxicam and curcumin potentiated the anti-pyretic effect on yeast-induced pyretic rats, anti-nociceptive effect on nociception induced in rats by formalin and heat, and anti-edematogenic activity in xylene-induced ear edema in rats in a dose-dependent manner. In carrageenan-induced paw inflammation in rats, meloxicam and curcumin co-loading (Mlx-Cur-NP) resulted in significant (p ≤ 0.05) inhibition of paw inflammation, reduction in TNF-α and PGE2 levels, downregulation of expressions of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6), as well as a decrease in histopathological changes and TNF-α immunoexpression in paw tissues. Moreover, Mlx-Cur-NP demonstrated noteworthy potentiation in pharmacological effects compared to free compounds and mono-compound-loaded nanoparticles. Thus, the association of meloxicam with curcumin in a biodegradable nanocarrier system could provide a promising anti-pyretic, anti-nociceptive, and anti-inflammatory therapeutic approach for acute conditions.

Transcranial direct current stimulation effects in the pain threshold and in oxidative stress parameters of neuropathic pain rats

Transcranial direct current stimulation (tDCS) can modulate cortical excitability and relieve neuropathic pain (NP), but the role of several biomarkers in this process is not well understood. This study aimed to analyze the effects of tDCS on biochemical parameters in rats with neuropathic pain (NP) induced by chronic constriction injury (CCI) of the right sciatic nerve. Eighty-eight male 60-day-old Wistar rats were divided into nine groups: control (C), control-electrode off (CEoff), control-tDCS (C-tDCS), sham-lesion (SL), sham-lesion electrode off (SLEoff), sham-lesion (SL-tDCS), lesion (L), lesion electrode off (LEoff), and lesion-tDCS (L-tDCS). After NP establishment, 20-minute bimodal tDCS for 8 consecutive days was applied to the rats. Fourteen days after the induction of NP, rats developed mechanical hyperalgesia with a decreased threshold, and at the end of treatment, an increase in the pain threshold was observed in NP rats. In addition, NP rats had increased levels of reactive species (RS) in the prefrontal cortex, while superoxide dismutase (SOD) activity was decreased in NP rats. In the spinal cord, nitrite levels and glutathione-S-transferase (GST) activity decreased in the L-tDCS group, and it was observed that increased levels in total sulfhydryl content for neuropathic pain rats were reversed by tDCS. In serum analyses, the neuropathic pain model increased the levels of RS and thiobarbituric acid-reactive substances (TBARS) and decreased the activity of butyrylcholinesterase (BuChE). In conclusion, bimodal tDCS increased total sulfhydryl content in the spinal cord of rats with neuropathic pain, positively modulating this parameter.

Caspase-11 contributes to pain hypersensitivity in the later phase of CFA-induced pain of mice

Chronic pain is a common disease that severely disrupts the quality of life. Persistent neuroinflammation and central sensitization play important roles in its pathogenesis. Caspase-11 is a critical modulator of inflammation of central nervous system. However, its role in chronic pain remains elusive. In this study, chronic pain and acute pain were induced via injecting complete Freund's adjuvant (CFA) and 5 % formalin into the plantar of the right hind paw of wild-type (WT) and Caspase-11 deficient (Caspase-11^-/-) mice, respectively. In WT mice, CFA injection significantly decreased the hind paw mechanical pain threshold in Von Frey test on 1-7 days after injection and increased the caspase-11 level of ipsilateral dorsal horn of spinal cord on day 2 and day 5 after injection. Compared to the WT mice, Caspase-11^-/- mice showed significantly higher mechanical pain threshold in the later phase of CFA-induced pain, but not in the early phase, and had no significant difference in 5 % formalin induced licking and flinching behavior. In addition, the microglial activation, and the mRNA levels of caspase-1 and IL-18 in the spinal cord of Caspase-11^-/- mice restored to baseline on the day 5 after CFA injection, but not in WT mice. Our data indicated that Caspase-11 contributed to persistent inflammation in ipsilateral dorsal horn of spinal cord, and consequently pain hypersensitivity in the later phase of CFA-induced pain.

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.

Thymus hirtus Willd. ssp. algeriensis Boiss. and Reut: A Comprehensive Review on Phytochemistry, Bioactivities, and Health-Enhancing Effects

Members of the Lamiaceae family are considered chief sources of bioactive therapeutic agents. They are important ornamental, medicinal, and aromatic plants, many of which are used in traditional and modern medicine and in the food, cosmetic, and pharmaceutical industries. In North Africa, on the Mediterranean side, there is the following particularly interesting Lamiaceous species: Thymus hirtus Willd. sp. Algeriensis Boiss. Et Reut. The populations of this endemic plant are distributed from the subhumid to the lower arid zone and are mainly employed as ethnomedicinal remedies in the following Maghreb countries: Algeria, Libya, Morocco, and Tunisia. In fact, they have been applied as antimicrobial agents, antispasmodics, astringents, expectorants, and preservatives for several food products. The species is commonly consumed as a tea or infusion and is used against hypercholesterolemia, diabetes, respiratory ailments, heart disease, and food poisoning. These medicinal uses are related to constituents with many biological characteristics, including antimicrobial, antioxidant, anticancer, anti-ulcer, anti-diabetic, insecticidal, and anti-inflammatory activities. This review aims to present an overview of the botanical characteristics and geographical distribution of Thymus algeriensis Boiss. Et Reut and its traditional uses. This manuscript also examines the phytochemical profile and its correlation with biological activities revealed by in vitro and in vivo studies.

Unraveling the Phytochemistry, Traditional Uses, and Biological and Pharmacological Activities of Thymus algeriensis Boiss. & Reut

Growing concern for public health has increased the need to change the paradigm towards a healthcare system that advocates holistic practices while reducing adverse effects. Herbal therapy is becoming an integral part of the therapeutic arsenal, and several successful plant-derived compounds/molecules are being introduced into the market. The medicinal plants belonging to the genus Thymus are among the most important species within the Lamiaceae family. One of them is Thymus algeriensis which is mainly distributed in the Mediterranean region. For a long time, this species has been used in traditional medicine to treat several disorders and diseases including inflammation, diabetes, rheumatism, digestive, and respiratory affections. This review describes the traditional uses, phytochemical composition, and biological and pharmacological activities of T. algeriensis extracts. Data were obtained using electronic databases such as SciFindern, ScienceDirect, Scopus, and Web of Science. Several plant-based extracts and a broad spectrum of identified secondary metabolites were highlighted and discussed with respective activities and modes of action. T. algeriensis represents a promising natural resource for the pharmaceutical industry mainly for antioxidant, anti-inflammatory, antimicrobial, and anticancer activities. Considering these findings, more research is needed to transmute the conventional uses of T. algeriensis into scientifically sound information. Moreover, extensive preclinical, clinical, toxicological, and pharmacokinetic trials on this species and its derivatives compounds are required to underpin the mechanisms of action and ensure its biosafety and efficiency. This comprehensive review provides a scientific basis for future investigations on the use of T. algeriensis and derived compounds in health maintenance and promotion and disease prevention.

The Effects of Nuclear Factor Erythroid 2 (NFE2)-Related Factor 2 (Nrf2) Activation in Preclinical Models of Peripheral Neuropathic Pain

Oxidative stress, resulting from an imbalance between the formation of damaging free radicals and availability of protective antioxidants, can contribute to peripheral neuropathic pain conditions. Reactive oxygen and nitrogen species, as well as products of the mitochondrial metabolism such as superoxide anions, hydrogen peroxide, and hydroxyl radicals, are common free radicals. Nuclear factor erythroid 2 (NFE2)-related factor 2 (Nrf2) is a transcription factor encoded by the NFE2L2 gene and is a member of the cap 'n' collar subfamily of basic region leucine zipper transcription factors. Under normal physiological conditions, Nrf2 remains bound to Kelch-like ECH-associated protein 1 in the cytoplasm that ultimately leads to proteasomal degradation. During peripheral neuropathy, Nrf2 can translocate to the nucleus, where it heterodimerizes with muscle aponeurosis fibromatosis proteins and binds to antioxidant response elements (AREs). It is becoming increasingly clear that the Nrf2 interaction with ARE leads to the transcription of several antioxidative enzymes that can ameliorate neuropathy and neuropathic pain in rodent models. Current evidence indicates that the antinociceptive effects of Nrf2 occur via reducing oxidative stress, neuroinflammation, and mitochondrial dysfunction. Here, we will summarize the preclinical evidence supporting the role of Nrf2 signaling pathways and Nrf2 inducers in alleviating peripheral neuropathic pain.

Potamogeton perfoliatus L. Extract Attenuates Neuroinflammation and Neuropathic Pain in Sciatic Nerve Chronic Constriction Injury-Induced Peripheral Neuropathy in Rats

Sciatic nerve injury is often associated with neuropathic pain and neuroinflammation in the central and peripheral nervous systems. In our previous work, Potamogeton perfoliatus L. displayed anti-inflammatory, antipyretic and analgesic properties, predominantly via the inhibition of COX-2 enzyme and attenuation of oxidative stress. Herein, we extended our investigations to study the effects of the plant's extract on pain-related behaviors, oxidative stress, apoptosis markers, GFAP, CD68 and neuro-inflammation in sciatic nerve chronic constriction injury (CCI) rat model. The levels of the pro-inflammatory marker proteins in sciatic nerve and brainstem were measured with ELISA 14 days after CCI induction. Pretreatment with the extract significantly attenuated mechanical and cold allodynia and heat hyperalgesia with better potential than the reference drug, pregabalin. In addition, CCI lead to the overexpression of prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), tumor necrosis alpha (TNFα), nuclear factor κB (NF-κB), cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and NADPH oxidase-1 (NOX-1) and decreased the catalase level in sciatic nerve and brainstem. The observed neuro-inflammatory changes were accompanied with glial cells activation (increased GFAP and CD68 positive cells), apoptosis (increased Bax) and structural changes in both brainstem and sciatic nerve. The studied extract attenuated the CCI-induced neuro-inflammatory changes, oxidative stress, and apoptosis while it induced the expression of Bcl-2 and catalase in a dose dependent manner. It also decreased the brainstem expression of CD68 and GFAP indicating a possible neuroprotection effect. Taking together, P. perfoliatus may be considered as a novel therapy for neuropathic pain patients after performing the required clinical trials.

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.