Effect of pioglitazone on neuropathic pain and spinal expression of TLR-4 and cytokines

Peroxisome proliferator-activated receptor gamma: A promising therapeutic target for the treatment of chronic pain

Chronic pain represents an incapacitating medical condition that profoundly impacts the patients' quality of life. Managing chronic pain poses a significant challenge for healthcare professionals due to its multifaceted nature and the limited effectiveness of current treatment options. Therefore, novel therapeutic interventions are crucially required for the management of chronic pain. Peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear receptor, exerts regulatory effects on physiological processes such as glucose and lipid metabolism. Emerging studies demonstrate that PPARγ is a critical regulator of the expression of various genes, including those of anti-inflammatory cytokines and antioxidant enzymes. Substantial evidence indicates decreased expression of PPARγ in the sciatic nerve, dorsal root ganglia, and spinal cord dorsal horn in animal models of chronic pain. Furthermore, natural or synthetic PPARγ agonists had inhibitory effects on nociceptive hypersensitivity in various animal models of chronic pain. This review summarizes and discusses preclinical evidence demonstrating the therapeutic potential of PPARγ agonists in chronic pain management. The available evidence indicates that PPARγ activation reduces chronic pain by inhibiting neuroinflammation and oxidative stress as well as modulation of opioidergic system. Overall, the use of PPARγ agonists is a promising therapeutic approach for treating chronic pain; however, further research regarding its detailed mechanisms is warranted.

PPARγ and AKt gene modulation following pregabalin and duloxetine combination for painful diabetic polyneuropathy

Aim: Diabetic peripheral neuropathy (DPN) induces chronic neuropathic pain in diabetic patients. Current treatments like pregabalin and duloxetine offer limited efficacy. This study evaluates combining pregabalin and duloxetine versus pregabalin alone for DPN pain relief, and explores gene modulation (PPARγ and Akt) to understand neuropathic pain's molecular basis.Materials & methods: Diabetic patients with DPN were randomized into groups receiving combination therapy or pregabalin alone for 4 weeks. Pain intensity, gene expression and quality of life were assessed.Results: Combination therapy significantly reduced pain, improved quality of life and upregulated PPARγ and Akt genes compared with monotherapy.Conclusion: Pregabalin and duloxetine combination therapy in DPN led to PPARγ mRNA upregulation and negative correlation of Akt gene expression with pain scores. This combination therapy effectively reduced pain and improved quality of life.Clinical Trial Registration: CTRI/2021/02/031068.

Pioglitazone ameliorates cisplatin-induced testicular toxicity by attenuating oxidative stress and inflammation via TLR4/MyD88/NF-κB signaling pathway

BACKGROUND

Cisplatin (CIS) is a chemotherapeutic agent widely used to cure several cancers. It exerts detrimental cellular effects that restrain its clinical application as an antineoplastic agent, as testicular damage. Pioglitazone (PIO), a peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist, is used to treat type-2 diabetes mellitus. PIO has been reported to exert anti-inflammatory and antioxidant effects in different tissues. The present study aimed to investigate the effect of PIO in a rat model of cisplatin-induced testicular toxicity and address the possible role of the Toll-like receptors (TLR4) / myeloid differentiation factor 88 (MyD88) / nuclear factor-kappa B (NF-kB) signal pathway.

METHODS

Rats received a single dose of cisplatin (7 mg/kg, IP) on the first day and PIO (10 mg/kg, P.O.) for 7 days. At the end of the treatment period, rats were killed. Testicular weights, histopathological alterations, and serum testosterone levels were determined. Moreover, tissue samples were collected for the estimation of oxidative stress parameters, inflammatory markers, and the determination of TLR4 /MyD88/NF-kB signaling.

RESULTS

Concurrent PIO administration with CIS markedly improved testicular weights, histopathological alteration, and serum testosterone level changes. Moreover, Concurrent PIO administration abrogated oxidative stress status and inflammatory markers caused by CIS administration. Furthermore, PIO inhibited the expression levels of TLR4, MyD88, and NF-κBp65, proteins that are activated by CIS administration.

CONCLUSION

These findings suggested that PIO can protect against cisplatin-induced testicular toxicity in rats through inhibition of the TLR4 /MyD88/NF-kB signal pathway.

Phytohormone abscisic acid ameliorates neuropathic pain via regulating LANCL2 protein abundance and glial activation at the spinal cord

Spinal neuroinflammation plays a critical role in the genesis of neuropathic pain. Accumulating data suggest that abscisic acid (ABA), a phytohormone, regulates inflammatory processes in mammals. In this study, we found that reduction of the LANCL2 receptor protein but not the agonist ABA in the spinal cord is associated with the genesis of neuropathic pain. Systemic or intrathecal administration of ABA ameliorates the development and pre-existence of mechanical allodynia and heat hyperalgesia in animals with partial sciatic nerve ligation (pSNL). LANCL2 is expressed only in microglia in the spinal dorsal horn. Pre-emptive treatment with ABA attenuates activation of microglia and astrocytes, ERK activity, and TNFα protein abundance in the dorsal horn in rats with pSNL. These are accompanied by restoration of spinal LANCL2 protein abundance. Spinal knockdown of LANCL2 gene with siRNA recapitulates the behavioral and spinal molecular changes induced by pSNL. Activation of spinal toll-like receptor 4 (TLR4) with lipopolysaccharide leads to activation of microglia, and over production of TNFα, which are concurrently accompanied by suppression of protein levels of LANCL2 and peroxisome proliferator activated-receptor γ. These changes are ameliorated when ABA is added with LPS. The anti-inflammatory effects induced by ABA do not requires G_i protein activity. Our study reveals that the ABA/LANCL2 system is a powerful endogenous system regulating spinal neuroinflammation and nociceptive processing, suggesting the potential utility of ABA as the management of neuropathic pain.

Peroxisome proliferator-activated receptor-gamma (PPARγ) and its immunomodulation function: current understanding and future therapeutic implications

INTRODUCTION

: Pain is a multidimensional experience involving the biological, psychological, and social dimensions of each individual. Particularly, the biological aspects of pain conditions are a response of the neuroimmunology system and the control of painful conditions is a worldwide challenge for researchers. Although years of investigation on pain experience and treatment exist, the high prevalence of chronic pain is still a fact.

AREAS COVERED

: Peroxisome proliferator-activated receptor-gamma (PPARγ) is a ligand-activated transcription factor belonging to the nuclear hormone receptor superfamily. It regulates several metabolic pathways, including lipid biosynthesis and glucose metabolism, when activated. However, PPARγ activation also has a critical immunomodulatory and neuroprotective effect.

EXPERT OPINION

: This review summarizes the evidence of synthetic or natural PPARγ ligands such as 15d-PGJ₂, epoxyeicosatrienoic acids, thiazolidinediones, and specialized pro-resolving mediators, representing an interesting therapeutic tool for pain control.

PPAR γ Prevents Neuropathic Pain by Down-Regulating CX3CR1 and Attenuating M1 Activation of Microglia in the Spinal Cord of Rats Using a Sciatic Chronic Constriction Injury Model

Background

Previous studies have proved that peripheral nerve injury is involved in the pathogenesis of neuropathic pain (NP). The peripheral nerve injury primes spinal M1 microglia phenotype and produces pro-inflammatory cytokines, which are responsible for neurotoxic and neuronal hyper-excitable outcomes. Spinal peroxisome proliferator-activated receptor gamma (PPAR γ) has been shown to play an anti-inflammatory role in the development of NP. However, the role of PPAR γ in attenuating the pathological pathway of spinal microgliosis is still unknown.

Methods

Sprague-Dawley rats (male, aged 8-10 weeks) were randomly divided into three groups, i.e., a control group, a NP group, and a NP + lentivirus encoding PPAR γ (LV-PPAR γ) group. The sciatic chronic constriction injury (CCI) model was used to induce NP in rats. Pain behavior was assessed by monitoring the rat hind-paw withdrawal threshold to mechanical stimuli and withdrawal latency to radiant heat. The LV-PPAR γ was intrathecally infused 1 day before CCI. Western blot analysis and real-time qPCR were used to detect the microglia phenotypic molecules and CX3CR1 expression in the spinal cord. In vitro, BV-2 microglia cells were transfected with LV-PPAR γ and incubated with lipopolysaccharides (LPS), and the levels of M1 microglia phenotypic molecules and CX3CR1 in BV-2 microglia cells were assessed by western blot analysis, real-time qPCR, and enzyme-linked immunosorbent assay.

Results

Preoperative intrathecal infusion of LV-PPAR γ attenuated pain in rats 7 days post-CCI. The M1-microglia marker, CX3CR1, and pro-inflammatory signaling factors were increased in the spinal cord of CCI rats, while the preoperative intrathecal infusion of LV-PPAR γ attenuated these changes and increased the expression of IL-10. In vitro, the overexpression of PPAR γ in BV-2 cells reduced LPS-induced M1 microglia polarization and the levels of CX3CR1 and pro-inflammatory cytokines.

Conclusion

Intrathecal infusion of LV-PPAR γ exerts a protective effect on the development of NP induced by CCI in rats. The overexpression of PPAR γ may produce both analgesic and anti-inflammatory effects due to inhibition of the M1 phenotype and CX3CR1 signaling pathway in spinal microglia.

Herbal Decoction Divya-Peedantak-Kwath Alleviates Allodynia and Hyperalgesia in Mice Model of Chemotherapy-Induced Peripheral Neuropathy via Modulation in Cytokine Response

The widely used cancer treatment, chemotherapy, causes severe long-term neuropathic pain in 30–40% cases, the condition clinically known as chemotherapy-induced peripheral neuropathy (CIPN). Approved conventional analgesics are sometimes ineffective, while others like opioids have undesirable side effects like addiction, seizures, and respiratory malfunctioning. Tricyclic antidepressants and anticonvulsants, although exhibit anti-allodynic effects in neuropathy, also have unpleasant side effects. Thus, alternative medicines are being explored for CIPN treatment. Despite scattered reports on different extracts from different plants having potential anti-allodynic effects against CIPN, no established medicine or formulation of herbal origin exists. In this study, efficacy of an herbal decoction, formulated based on ancient medicinal principles and protocols for treating neuropathic pain, Divya-Peedantak-Kwath (DPK), has been evaluated in a paclitaxel (PTX)-induced peripheral neuropathic mouse model. We observed that DPK has prominent anti-allodynic and anti-hyperalgesic effects and acts as a nociceptive modulator for CIPN. With exhibited antioxidative effects, DPK restored the redox potential of the sciatic nerves to the normal. On histopathological evaluation, DPK prevented the PTX-induced lesions in the sciatic nerve, in a dose-dependent manner. It also prevented inflammation by modulating the levels of pro-inflammatory cytokines involved in CIPN pathogenesis. Our observations evinced that DPK can alleviate CIPN by attenuating oxidative stress and concomitant neuroinflammation through immune modulation.

PPARγ: Potential Therapeutic Target for Ailments Beyond Diabetes and its Natural Agonism

Intense research interests have been observed in establishing PPAR gamma as a therapeutic target for diabetes. However, PPARγ is also emerging as an important therapeutic target for varied disease states other than type 2 diabetes like neurodegenerative disorders, cancer, spinal cord injury, asthma, and cardiovascular problems. Furthermore, glitazones, the synthetic thiazolidinediones, also known as insulin sensitizers, are the largely studied PPARγ agonists and the only ones approved for the treatment of type 2 diabetes. However, they are loaded with side effects like fluid retention, obesity, hepatic failure, bone fractures, and cardiac failure; which restrict their clinical application. Medicinal plants used traditionally are the sources of bioactive compounds to be used for the development of successful drugs and many structurally diverse natural molecules are already established as PPARγ agonists. These natural partial agonists when compared to full agonist synthetic thiazolidinediones led to weaker PPARγ activation with lesser side effects but are not thoroughly investigated. Their thorough characterization and elucidation of mechanistic activity might prove beneficial for counteracting diseases by modulating PPARγ activity through dietary changes. We aim to review the therapeutic significance of PPARγ for ailments other than diabetes and highlight natural molecules with potential PPARγ agonistic activity.

PPARγ activation mitigates mechanical allodynia in paclitaxel-induced neuropathic pain via induction of Nrf2/HO-1 signaling pathway

Paclitaxel-induced neuropathic pain (PINP) is a dose-limiting side effect and is refractory to widely used analgesic drugs. Previous studies have demonstrated a protective role of peroxisome proliferator-activated receptor gama (PPARγ) in neuropathic pain. However, whether PPARγ activation could alleviate PINP remains to be elucidated. Our previous study has validated the analgesic effect of oltipraz, an nuclear factor erythroid-2 related factor 2 (Nrf2) activator, in a rat model of PINP. In this study, we tested the hypothesis that rosiglitazone, a selective agonist of PPARγ, could attenuate PINP through induction of Nrf2/heme oxygenase-1 (HO-1) signaling pathway. Paclitaxel was injected intraperitoneally on four alternate days to induce neuropathic pain. Paw withdrawal threshold was used to evaluate mechanical allodynia. Western blot and immunofluorescence were used to examine the expression and distribution of PPARγ, Nrf2 and HO-1 in the spinal cord. Our results showed that rosiglitazone attenuated established PINP and delayed the onset of PINP via activation of PPARγ, which were reversed by PPARγ antagonist GW9662. Moreover, rosiglitazone inhibited downregulation of PPARγ in the spinal cord of PINP rats. Furthermore, the analgesic effect of rosiglitazone against PINP was abolished by trigonelline, an Nrf2 inhibitor. Finally, rosiglitazone significantly increased expression of Nrf2 and HO-1 in the spinal cord of PINP rats. Collectively, these results indicated that PPARγ activation might mitigate PINP through activating spinal Nrf2/HO-1 signaling pathway. Our results may provide an alternative option for PINP patients.

Neuroprotective effects of ranolazine versus pioglitazone in experimental diabetic neuropathy: Targeting Nav1.7 channels and PPAR-γ

Diabetic neuropathy (DN) is a common complication of diabetes mellitus (DM). Pathophysiology of DN includes inflammation and changes in expression and function of voltage-gated sodium channels (Nav) in peripheral nerves; and central reduction of Peroxisome Proliferator Activated Receptor-Gamma (PPAR-γ) expression.

AIM

This study explored the effect of ranolazine (RN) versus pioglitazone (PIO) in DN induced in rats. The role of sciatic interleukin (IL)-1β, tumor necrosis factor-alpha (TNF)-α, Nav1.7, and spinal PPAR-γ expressions were determined.

MATERIALS AND METHODS

For induction of Type-2 DM, 40 high fat diet-fed rats were challenged by a single dose of intraperitoneal streptozotocin (30 mg/kg). One week later, oral PIO (10 mg/kg; once daily) or RN (20, 50 and 100 mg/kg; twice daily) were administered for six weeks. Weekly body weight and fasting blood sugar (FBS) were measured. Rats were tested for thermal hyperalgesia and mechanical allodynia. At the end of the experiment, sciatic nerves homogenates were examined for TNF-α and IL-1B levels, and Nav1.7 channel expression. Segments of spinal cords were investigated for the PPAR-γ gene expression. Evaluation of histopathology of sciatic nerves and spinal cords were done.

KEY FINDINGS

In diabetic rats, PIO and RN individually improved evoked-pain behaviors, reduced sciatic TNF-α and 1L-1B levels; downregulated expressional levels of Nav1.7 channels; and increased the spinal PPAR-γ gene expression. RN in the dose of 100 mg/kg/day showed the most advantageous effects.

SIGNIFICANCE

RN has neuroprotective effects in Type-2 diabetes-induced DN. Further studies of combined RN-PIO treatment are recommended, especially in diabetic patients with cardiovascular co-morbidity.

Crosstalk between Peroxisome Proliferator-Activated Receptors and Toll-Like Receptors: A Systematic Review

As one of the four major families of pattern recognition receptors (PRRs), toll like receptors (TLRs) are crucial and important components of the innate immune system. Peroxisome proliferatoractivated receptors (PPARs) with three isoforms are transcription factors classified as a subfamily of nuclear receptor proteins, and are of significant regulatory activity in cellular differentiation, development, metabolism, and tumorigenesis. It is well established that PPARs agonists display anti-inflammatory effects through inhibition of the nuclear factor-kappa B (NF-κB) pathway, a key regulator of immune and inflammatory responses, in a sense that TLRs signaling pathways are mainly toward activation of NF-κB. Through a systematic review of previous studies, we aimed to address and clarify the reciprocal interaction between TLRs and PPARs in hope to find alternative therapeutic approaches for inflammatory diseases. Among the available scientific database, 31 articles were selected for this review. A comprehensive review of this database confirms the presence of a cross-talk between PPARs and TLRs, indicating that not only PPARs stimulation may affect the expression level of TLRs via several mechanisms leading to modulating TLRs activities, but also TLRs have the potential to moderate the expression of PPARs. We, therefore, conclude that, as a key regulator of the innate immune system, the interaction between PPARs and TLRs is a potential therapeutic target in disease treatment.

Evidence of a PPARγ-mediated mechanism in the ability of Withania somnifera to attenuate tolerance to the antinociceptive effects of morphine

Notwithstanding the experimental evidence indicating Withania somnifera Dunal roots extract (WSE) ability to prolong morphine-elicited analgesia, the mechanisms underlying this effect are largely unknown. With the aim of evaluating a PPARγ-mediated mechanism in such WSE effects, we verified the ability of the PPARγ antagonist GW-9662 to modulate WSE actions. Further, we evaluated the influence of GW-9662 upon WSE / morphine interaction in SH-SY5Y cells since we previously reported that WSE hampers the morphine-induced μ-opioid receptor (MOP) receptor down-regulation. Nociceptive thresholds / tolerance development were assessed in different groups of rats receiving vehicles (control), morphine (10 mg/kg; i.p.), WSE (100 mg/kg, i.p.) and PPARγ antagonist GW-9662 (1 mg/kg; s.c.) in acute and chronic schedules of administration. Moreover, the effects of GW-9662 (5 and 10 μM) applied alone and in combination with morphine (10 μM) and/or WSE (0.25 and 1.00 mg/mL) on the MOP gene expression were investigated in cell cultures. Data analysis revealed a functional effect of the PPARγ antagonist in attenuating the ability of WSE to prolong morphine analgesic effect and to reduce tolerance development after repeated administration. In addition, molecular experiments demonstrated that the blockade of PPARγ by GW-9662 promotes MOP mRNA down-regulation and counteracts the ability of 1.00 mg/mL of WSE to keep an adequate MOP receptor availability. In conclusion, our results support the involvement of a PPARγ-mediated mechanism in the WSE effects on morphine-mediated nociception and the likely usefulness of WSE in lengthening the analgesic efficacy of opioids in chronic therapy.

Pioglitazone improves visceral sensation and colonic permeability in a rat model of irritable bowel syndrome

Visceral hypersensitivity and impaired gut barrier with minor inflammation are considered to play an important role in the pathophysiology of irritable bowel syndrome (IBS). Since pioglitazone is known to have anti-inflammatory property, we hypothesized that pioglitazone is beneficial for treating IBS. In this study, the effect was tested in rat IBS models such as lipopolysaccharide or repeated water avoidance stress-induced visceral allodynia and increased colonic permeability. Pioglitazone blocked these visceral changes, and GW9662, a peroxisome proliferator-activated receptor gamma (PPAR-γ) antagonist fully reversed the effect by pioglitazone. These results suggest that PPAR-γ activation by pioglitazone may be useful for IBS treatment.

miRNA-146a attenuates inflammation in an in vitro spinal cord injury model via inhibition of TLR4 signaling

The present study evaluated the anti-inflammatory effect of microRNA (miR)-146a in a spinal cord injury (SCI) rat model and in vitro model, and explored possible underlying mechanisms of this effect. miR-146a expression was analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 content was measured using ELISA kits. Inducible nitric oxide synthase (iNOS), prostaglandin E2 (PGE2), Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88) and phosphorylated (p)-nuclear factor (NF)-κB were measured using western blotting. In the SCI rat model, miR-146a expression was downregulated. In the in vitro model, downregulation of miR-146a increased inflammation, enhanced iNOS and PGE2 protein expression and induced TLR4, MyD88 and NF-κB expression. Overexpression of miR-146a reduced inflammation, iNOS and PGE2 protein expression, and suppressed TLR4, MyD88 and NF-κB expression in the in vitro SCI model. The inhibition of TLR4 attenuated the proinflammatory effects of anti-miR-146a in the in vitro SCI model. The results indicate that miR-146a reduces inflammation in an SCI model through the TLR4-NF-κB signaling pathway. The present study demonstrated that miR-146a may be a promising therapeutic agent for SCI.

PPARs and pain

Chronic pain is a common cause of disability worldwide and remains a global health and socio-economic challenge. Current analgesics are either ineffective in a significant proportion of patients with chronic pain or associated with significant adverse side effects. The PPARs, a family of nuclear hormone transcription factors, have emerged as important modulators of pain in preclinical studies and therefore a potential therapeutic target for the treatment of pain. Modulation of nociceptive processing by PPARs is likely to involve both transcription-dependent and transcription-independent mechanisms. This review presents a comprehensive overview of preclinical studies investigating the contribution of PPAR signalling to nociceptive processing in animal models of inflammatory and neuropathic pain. We examine current evidence from anatomical, molecular and pharmacological studies demonstrating a role for PPARs in pain control. We also discuss the limited evidence available from relevant clinical studies and identify areas that warrant further research. LINKED ARTICLES: This article is part of a themed section on 8^th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.

Rosmarinic acid attenuates development and existing pain in a rat model of neuropathic pain: An evidence of anti-oxidative and anti-inflammatory effects

BACKGROUND

We aimed to investigate the potential prophylactic and curative effects of rosmarinic acid, one of the main constituents of rosemary, on the neuropathic pain induced by chronic constriction injury (CCI) in rats.

MATERIALS AND METHODS

CCI was used to induce peripheral neuropathic pain. In prophylactic groups, rosmarinic acid (10, 20, and 40 mg/kg, i.p.) was administered from the day of surgery (day 0) for 14 days. In treatment group, rosmarinic acid (40 mg/kg) was given from day 5 (after the pain was established), for 7 days. The degree of mechanical allodynia, cold allodynia, and heat hyperalgesia were measured on days 0, 3, 5, 7, 10 and 14 post-surgery. The open field test was carried out to assess locomotor activity of animals. Lumbar spinal cord levels of astroglia activation marker, glial fibrillary acidic protein (GFAP), microglial activation marker, ionized calcium-binding adapter molecule 1 (Iba-1), toll-like receptor 4 (TLR-4), tumor necrosis factor alpha (TNF-α), inducible isoform of nitric oxide synthase enzyme (iNOS) and apoptotic factors were quantified via western blot on days 7 and 14.

RESULTS

CCI rats showed a significant mechanical allodynia, cold allodynia and thermal hyperalgesia, compared to sham ones on day 3, persisted up to day 14 post-CCI. Rosmarinic acid was able to prevent and also attenuate CCI-induced behavioral features in prophylactic as well as treatment groups, respectively. A significant increase in the levels of TNF-α, iNOS, apoptotic factors (Bax, caspases 3, 9), Iba-1, TLR-4, and GFAP was observed on both days 7 and 14, which was suppressed by 14 days administration of rosmarinic acid.

CONCLUSION

These findings further support the use of rosemary in traditional medicine to alleviate pain. Rosmarinic acid could be a promising compound in prophylaxis and treatment of neuropathic pain. Anti-apoptotic and anti-inflammatory effects of rosmarinic acid may have important roles in the observed antinociceptive properties.

Ulinastatin inhibited sepsis-induced spinal inflammation to alleviate peripheral neuromuscular dysfunction in an experimental rat model of neuromyopathy

Sepsis initiates a neuroinflammatory cascade that contributes to spinal cord inflammation and behavioral impairment, and Toll-like receptor 4 (TLR4) is an important mediator of this cascade. In this study, we tested the hypothesis that ulinastatin (ULI) inhibits sepsis-induced spinal inflammation to alleviate peripheral neuromuscular dysfunction through the TLR4/myeloid differentiation factor 88 (MyD88)/NF-κB signaling pathway. Muscular function, spinal cord water content, and cytokine levels of spinal cord were tested in TLR4-inhibited rats subjected to cecal ligation and puncture (CLP). The normal rats were intrathecally injected with different concentrations of ULI or normal saline 60 min before CLP. At 24 h after CLP, the activation of microglia/macrophage was detected by immunofluorescence staining; and the cytokines were assayed by ELISA. The protein expression level of the TLR4 and its downstream effectors (MyD88 and NF-κB), the neuregulin-1, and the γ- and α7-nicotinic acetylcholine receptor was measured using western blotting. The protein expression of TLR4 in the spinal cord reached a maximum at 24 h post-CLP. Compared to the sham rats, the TLR4-inhibited rats showed attenuated functional impairment and cytokine release. ULI (5000 U/kg ) treatment pre-CLP significantly reduced the number of TLR4-positive microglia/macrophages as well as inflammatory mediator release in septic rats. Furthermore, the levels of TLR4, MyD88, and NF-κB and the expression level of γ-/α7-nicotinic acetylcholine receptors also decreased after ULI treatment. ULI administration may improve patient outcome by reducing the spinal inflammation through a mechanism involving the TLR4/MyD88/NF-κB signaling in sepsis.