Antinociceptive effects of matrine on neuropathic pain induced by chronic constriction injury

Abstract

Context: Sophora alopecuroides L. (Leguminosae) is a commonly used Chinese herbal drug that possesses antipyretic, anti-inflammatory and analgesic effects. Among various alkaloids isolated from S. alopecuroides, matrine has been identified as the major bioactive component contributing to a variety of pharmacological effects, and studies have also shown that matrine has an analgesic effect.

Objective: To investigate the antinociceptive effects of matrine on neuropathic pain induced by chronic constriction injury (CCI) in mice.

Materials and methods: The von Frey, plantar, cold-plate, locomotor activity and rota-rod test were performed to assess the degree of mechanical, radiant, thermal, spontaneous locomotor activity and motor coordination changes respectively, at different time intervals, i.e., one day before surgery and 7, 8, 10, 12 and 14 days post surgery. Matrine was administered from the 8th day after the surgery for seven days.

Results: Our present study shows that matrine at the dose of 30?mg/kg i.p. increased the paw withdrawal threshold (0.88?±?0.16), paw withdrawal latency (7.01?±?0.11) and the counts of paw withdrawal (19.7?±?1.15) from the day 8 for the nerve injured paw compared to the CCI group (0.18?±?0.04, 4.62?±?0.18, 44.3?±?2.99, respectively). Matrine, in a dose-dependent effect, was also found to produce a protective role in both plantar and cold-plate tests. The analysis of the effect supports the hypothesis that matrine is useful in neuropathic pain therapy.

Discussion and conclusion: The results of this study suggest that matrine could be useful in the treatment of different kinds of neuropathic pains as an adjuvant to conventional medicines.     

GLT-1激动剂头孢曲松钠对慢性神经病理性痛的影响

目的：探讨头孢曲松钠（Ceftriaxone,Cef）对慢性神经病理性痛过敏及GLT-1表达的影响。方法雄性SD大鼠90只,随机分为Sham组、CCI 14 d组、Cef预防组、 Cef治疗组,后2组设腹腔注射NS组为对照,在不同时间点测定热缩足反射潜伏期;另设CCI 1 d、4 d、7 d组。应用免疫组化观察不同时间点脊髓后角GLT-1表达的变化。结果CCI诱导大鼠产生了热痛敏,腹腔注射NS对CCI诱导的热痛敏无影响。 Cef预防组大鼠CCI侧后肢热缩足反射潜伏期于CCI后第5天、第7天明显延长（ P ＜0°．05）;Cef 治疗组大鼠CCI侧后肢热缩足反射潜伏期在术后第11天、第14天明显延长（ P ＜0．05）。免疫组化检测发现,Cef预防组和Cef治疗组分别抑制和逆转了GLT-1在CCI后期表达的降低。结论 Cef可通过上调GLT-1的表达对慢性神经病理性痛起到预防和治疗作用。     

阿霉素减轻坐骨神经慢性缩窄性损伤大鼠的神经病理性疼痛及其机制

目的观察阿霉素(DOX)对坐骨神经慢性缩窄性损伤(CCI)模型大鼠的镇痛作用,并从形态学及组织凋亡蛋白的角度对其机制进行分析。方法将SD大鼠随机分为4组:假手术组(Sham)、CCI模型组(Model)、假手术+阿霉素5 mg·kg^-1组(Sham+DOX)、CCI模型+阿霉素5 mg·kg^-1组(Model+DOX)。造模成功后,各组采用尾静脉注射的方式给药,Sham组和Model组给予等量生理盐水,检测各组大鼠机械痛阈值和热痛阈值。在行为学检测结束后,即手术后d 15取大鼠右侧L4-5DRG,观察DRG细胞形态、超微结构及DOX的分布情况,采用Western blot法测定DRG组织中Bax、Bcl-2、PKCɑ、PKCδ及PKCε的蛋白表达。结果静脉注射DOX可在DRG组织检测到其自发荧光表达。与Sham组相比,Sham+DOX组痛阈值在整个观察期未见差别,而Model组在术后d 7痛阈值明显降低。与Model组相比,Model+DOX组的痛阈值在给药后明显回升,并表现出DRG细胞明显损伤,Bax/Bcl-2升高以及PKCδ、PKCε的蛋白表达量降低等现象。结论 DOX静脉注射可以到达并蓄积于DRG组织,明显减轻CCI大鼠的疼痛反应,这一作用与其降低PKCδ和PKCε的蛋白表达,诱导DRG的凋亡有关。     

Activation of the transient receptor potential vanilloid-1 (TRPV1) channel opens the gate for pain relief

Pharmacological modulation of the transient receptor potential vanilloid-1 (TRPV1) receptor function offers a promising means of producing pain relief at the level of the primary sensory neuron. In this issue of the BJP, the pharmacological approaches and the available experimental data that focus on the TRPV1 receptor to achieve therapeutically useful alleviation of pain and inflammation are reviewed. The potentials to inactivate TRPV1 receptor function by site- and modality-specific TRPV1 antagonists, uncompetitive TRPV1 blockers and drugs interfering with TRPV1 sensitization, are evaluated. A crucial issue of producing pain relief at the level of the nocisensor remains whether it can be achieved solely through inactivation of the TRPV1 receptor or TRPV1 agonist-induced defunctionalization of the whole primary afferent neuron is required. The accumulated evidence indicates that both pharmacological modulation of the intracellular trafficking of the TRPV1 receptor and defunctionalization of the nocisensors by TRPV1 agonists are promising novel approaches to tame the TRPV1 receptor.     

Advances in the development of TRPV1 antagonists

Transient receptor potential V1 (TRPV1) is a nonspecific cation channel subject to polymodal activation. TRPV1, originally termed vanilloid receptor 1, can be activated by the prototypical vanilloid capsaicin as well as decreases in extracellular pH and increases in temperature. The neuronal expression and biology surrounding TRPV1 suggest that it plays a significant role in the establishment and maintenance of various pain states as well as a potential role for TRPV1 in cough and bladder function. This review outlines the potential mechanism(s) by which activation of TRPV1 leads to pain and hyperalgesia, lessons learned via the development of antagonists and the current status of the development of therapeutic entities for validation within a clinical setting.     

γ-氨基丁酸转运体抑制剂NO-711术前鞘内注射对坐骨神经慢性挤压伤大鼠神经病理性痛觉过敏的影响

γ-氨基丁酸是哺乳动物中枢神经系统主要的抑制性神经递质。近年来的研究发现GABA递质受体系统在伤害性信息传递和调节方面起着重要的作用。定位在突触前膜和神经胶质细胞的转运体GAT1是最重要的神经递质转运体之一，能快速摄取GABA从而终止其抑制作用。GABA转运体抑制剂已经被广泛用于癫痫研究，但是这种药是否对疼痛动物或人有镇痛作用仍然不是十分清楚。本实验目的是在大鼠神经病理痛模型建立前鞘内给予NO-711，观察其对大鼠热痛敏和触诱发痛的影响。     

Increase in hemokinin-1 mRNA in the spinal cord during the early phase of a neuropathic pain state

Background and purpose:

Substance P (SP), a representative member of the tachykinin family, is involved in nociception under physiological and pathological conditions. Recently, hemokinin-1 (HK-1) was identified as a new member of this family. Although HK-1 acts on NK₁ tachykinin receptors that are thought to be innate for SP, the roles of HK-1 in neuropathic pain are still unknown.

Experimental approach:

Using rats that had been subjected to chronic constrictive injury (CCI) of the sciatic nerve as a neuropathic pain model, we examined the changes in expression of SP- and HK-1-encoding genes (TAC1 and TAC4, respectively) in the L4/L5 spinal cord and L4/L5 dorsal root ganglia (DRGs) in association with changes in pain-related behaviours in this neuropathic pain state.

Key results:

The TAC4 mRNA level was increased on the ipsilateral side of the dorsal spinal cord, but not in DRGs, at day 3 after CCI. In contrast, the TAC1 mRNA level was significantly increased in the DRGs at day 3 after CCI without any changes in the dorsal spinal cord. Analysis of a cultured microglial cell line revealed the presence of TAC4 mRNA in microglial cells. Minocycline, an inhibitor of microglial activation, blocked the increased expression of TAC4 mRNA after CCI and inhibited the associated pain-related behaviours and microglial activation in the spinal cord.

Conclusions and implications:

The present results suggest that HK-1 expression is increased at least partly in activated microglial cells after nerve injury and is clearly involved in the early phase of neuropathic pain.     

脊髓p38MAPK在大鼠背根节慢性压迫神经病理性疼痛中的作用

目的观察背根节慢性压迫(chronic compression of dorsal root ganglion,CCD)痛大鼠脊髓p-p38MAPK表达的变化,探讨p38MAPK与慢性神经病理性痛的相关性。方法♂SD大鼠36只,随机分为正常组(Naive组,n=4)、假手术组(Sham组,n=16)和背根节慢性压迫组(CCD组,n=16),Sham组和CCD组又分别分为5,7,14d和21d4个亚组(n=4),分别用免疫印迹法(Westernblot)检测各组大鼠脊髓磷酸化p38丝裂原活化蛋白激酶(p-p38MAPK)表达的变化。结果3组大鼠脊髓均见p-p38MAPK蛋白表达。Naive组和Sham组间比较差异无统计学意义。CCD组大鼠脊髓p-p38MAPK蛋白表达较Naive组和Sham组明显增多;与Sham组相比,CCD后5,7,14,21d各组大鼠脊髓背角神经元胞质p-p38MAPK蛋白分别增加了138·1%(P<0·01)、184·3%(P<0·01)、247·4%(P<0·01)和90·4%(P<0·05)。胞核p-p38MAPK蛋白分别增加了167·3%(P<0·01)、177·8%(P<0·01)、262·7%(P<0·01)和72·7%(P<0·05)。结论在CCD大鼠模型中,脊髓p38MAPK的活化与背根节慢性压迫致神经病理性痛的形成和发展存在密切联系。     

鞘内注射米诺四环素对慢性坐骨神经结扎大鼠机械痛敏和热痛敏的影响

目的观察鞘内注射小胶质细胞抑制剂米诺四环素对慢性坐骨神经结扎大鼠机械痛敏和热痛敏的影响。方法所有大鼠术前8d鞘内置管,用机械缩足反射阈值和热缩足潜伏期来分别评价大鼠机械痛敏和热痛敏。前给药组:生理盐水10μl或米诺四环素50μg,于坐骨神经结扎前1d开始持续到术后1d(每天2次)鞘内注射,机械缩足反射阈值和热缩足潜伏期分别于术前2d,术后1,3,5,7,14d测定;后给药组:坐骨神经结扎后7d,鞘内注射1次生理盐水10μl或米诺四环素50μg,其对机械缩足反射阈值和热缩足潜伏期的影响分别于给药后0.5、1、2、4、8h测定。结果CCI大鼠从术后1d形成稳定的热痛敏和机械痛敏,前鞘内注射米诺四环素明显增加CCI大鼠MWT和TWL(P<0.05,P<0.01),相反,后鞘内注射米诺四环素对CCI大鼠MWT和TWL无明显影响。结论前鞘内注射米诺四环素明显抑制CCI大鼠机械痛敏和热痛敏,提示小胶质细胞的活化参与慢性坐骨神经结扎引发神经病理痛的形成。     

LASSBio-881: an N-acylhydrazone transient receptor potential vanilloid subfamily type 1 antagonist orally effective against the hypernociception induced by capsaicin or partial sciatic ligation

Background and purpose:

Compound LASSBio-881 is an orally effective antinociceptive that binds to cannabinoid receptors and is active mainly on the neurogenic component of pain models. We investigated whether transient receptor potential vanilloid subfamily type 1 (TRPV1) channels are involved in the effects of LASSBio-881.

Experimental approach:

Modulation of capsaicin (CAP)- and low pH-induced currents was evaluated in TRPV1-expressing Xenopus oocytes. In vivo effects were evaluated in CAP-induced acute and inflammatory changes in nociception, as well as in partial sciatic ligation-induced thermal hypernociception.

Key results:

LASSBio-881 inhibited TRPV1 currents elicited by CAP with an IC₅₀ of 14 µM, and inhibited proton-gated currents by 70% at 20 µM. Functional interaction with CAP was surmountable. Locally applied LASSBio-881 decreased time spent in CAP-elicited nocifensive behaviour by 30%, and given orally it reduced measures of CAP- or carrageenan-evoked thermal hypernociception by 60 and 40% respectively. In addition, LASSBio-881 decreased the paw withdrawal responses to thermal stimuli of animals with sciatic neuropathy 7–11 days after nerve ligation, at a dose of 300 µmol·kg⁻¹·day⁻¹ p.o. At this dose, hyperthermia was not observed within 4 h following oral administration.

Conclusions and implications:

LASSBio-881 is a TRPV1 antagonist that apparently competes with CAP. Accordingly, LASSBio-881 inhibited nociception in models of acute, inflammatory and neuropathic pain presumed to involve TRPV1 signalling. These in vivo actions were not hindered by hyperthermia, a common side effect of other TRPV1 antagonists. We propose that the antinociceptive properties of LASSBio-881 are due to TRPV1 antagonism, although other molecular interactions may contribute to the effects of this multi-target drug candidate.     

Rosmarinic acid ameliorates acetaminophen-induced acute liver injury in mice via RACK1/TNF-α mediated antioxidant effect

ContextRosmarinic acid (RA) dose-dependently ameliorates acetaminophen (APAP) induced hepatotoxicity in rats. However, whether RA hepatoprotective effect is by regulating RACK1 and its downstream signals is still unclear.ObjectiveThis study explores the RA protective effect on APAP-induced ALI and its mechanism.Materials and methodsSixty Kunming mice 6–8 weeks old were randomly separated into six groups (n = 10) and pre-treated with normal saline, ammonium glycyrrhetate (AG) or RA (10, 20 or 40 mg/kg i.p./day) for two consecutive weeks. Then, APAP (300 mg/kg, i.g.) was administrated to induce ALI, except for the control. Serum alanine/aspartate aminotransferases (ALT and AST), malondialdehyde (MDA), superoxide dismutase (SOD) and histopathology were used to authenticate RA effect. The liver RACK1 and TNF-α were measured by western blot.ResultsCompared with the APAP group, different dosages RA significantly decreased ALT (52.09 ± 7.98, 55.13 ± 10.19, 65.08 ± 27.61 U/L, p < 0.05), AST (114.78 ± 19.87, 115.29 ± 31.91, 101.78 ± 21.85 U/L, p < 0.05), MDA (2.37 ± 0.87, 2.13 ± 0.87, 1.86 ± 0.39 nmol/mg, p < 0.01) and increased SOD (306.178 ± 90.80, 459.21 ± 58.54, 444.01 ± 78.09 U/mg, p < 0.05). With increasing doses of RA, RACK1 and TNF-α expression decreased. Moreover, the RACK1 and TNF-α levels were positively correlated with MDA (r = 0.8453 and r = 0.9391, p < 0.01).Discussion and conclusionsOur findings support RA as a hepatoprotective agent to improve APAP-induced ALI and the antioxidant effect mediated through RACK1/TNF-α pathway.     

鞘内注射GABA转运体-1抑制剂NO-711对神经病理痛大鼠脊髓Fos蛋白表达的影响

目的:观察脊髓水平GABA转运体-1(γ-aminobutyric acid transporter-1,GAT-1)抑制剂NO-711对坐骨神经慢性松结扎(chronic constriction injury,CCI)大鼠机械痛敏和热痛敏以及Fos蛋白表达的影响,探讨NO-711抗伤害性的可能机制。方法:雄性SD大鼠84只,随机分为4组(n=21):假手术生理盐水组、假手术抑制剂组、神经损伤生理盐水组和神经损伤抑制剂组。各组大鼠CCI前5 d进行鞘内置管,在术前测定基础机械性缩足反射阈值(mechanical withdrawal threshold,MWT)和热缩足潜伏期(thermal withdrawal laten-cy,TWL)及Fos蛋白的表达,CCI后5 d鞘内注射100μg NO-711或生理盐水,测定节扎前、给药前、给药后0.5,1,2,4和8 h大鼠MWL和TWL及Fos蛋白的表达。结果:与给药前和神经损伤生理盐水组相比,神经损伤抑制剂组大鼠在给药后机械痛敏和热痛敏以及Fos蛋白的表达均逐渐降低,并随时间的延长又逐渐恢复到给药前水平,在给药后1 h时作用最明显,并一直持续到给药后4 h...     

不同材料制备大鼠神经病理性疼痛CCI模型的比较

目的比较肠线、丝线、PE套管3种材料制备的CCI模型的造模效果。方法用肠线、丝线4道轻结扎大鼠坐骨神经干,或用PE90套管造成大鼠坐骨神经干慢性压迫性损伤,测定伤足底热痛阈和机械痛阈评定模型的效果。结果3种材料造模后d9和d15测定热痛阈和机械痛阈,比造模前均下降,其中肠线CCI模型对热痛阈的影响强于丝线或PE管CCI模型(d9,P<0·05;d15,P<0·01)。3种材料制备的CCI模型间机械痛阈差异无显著性。结论3种材料均可造成满意的CCI模型,但肠线造模的效果优于丝线和PE管。     

肉毒毒素A对慢性坐骨神经结扎大鼠机械痛敏和热痛敏的影响

目的探讨肉毒毒素A(botulinum toxin type A,BoNT-A)后处理对神经病理性疼痛大鼠疼痛行为学的影响。方法建立SD大鼠右侧慢性坐骨神经结扎模型(chronic con-striction injury of sciatic nerve,CCI)。CCI术后d3始,CCI同侧肢体足底注射BoNT-A7.5、15、30U·kg-1或等容积生理盐水,或对侧肢体足底注射BoNT-A15或30U·kg-1。分别于术前、术后1、3、5、7、14d,测定大鼠的机械缩足反射阈值(MWT)和热缩足潜伏期(TWL)。结果CCI手术同侧足底皮下注射BoNT-A可以增加大鼠的MWT和TWL,对侧应用BoNT-A对MWT和TWL无影响。结论BoNT-A可以通过局部作用减轻CCI手术同侧肢体的机械痛敏和热痛敏。     

Role of serotonin 5-HT<Subscript>1A</Subscript> and opioid receptors in the antiallodynic effect of tramadol in the chronic constriction injury model of neuropathic pain in rats

Rationale Tramadol (1RS, 2RS)-2-[(dimethylamino)-methyl]-1-(3-methoxyphenyl)-cyclohexanol) is an atypical centrally acting analgesic agent with weak opioid receptor affinity that, like some antidepressants, enhances the extraneuronal concentrations of the monoamine neurotransmitters, noradrenaline and serotonin, by interfering with their re-uptake and release mechanisms. Objectives The present study was undertaken to evaluate the potential role of 5-HT_1A receptors and opioids receptors in the analgesic effect of tramadol in neuropathic pain. With this aim, the effect of either a selective 5-HT_1A receptor antagonist (WAY-100635, N-2-[4-(2-methoxyphenyl-1-piperazinyl]ethyl]-N-2-pyridinylcyclohexane carboxamide) or a selective 5-HT_1A receptor agonist (8-OH-DPAT, 8-hydroxy-2-(di-n-propylamine) tetralin hydrobromide) or an opioid receptor antagonist (naloxone; naloxone hydrochloride dihydrate) was investigated in combination with tramadol by means of the cold-plate test in the chronic constriction injury model in rats. Results The results showed that WAY-100635 (0.8 mg/kg) significantly enhanced the antiallodynic effect of non-effective doses of tramadol (5–10 mg/kg). In contrast, 8-OH-DPAT (0.5 mg/kg) counteracted the antiallodynic effect of an effective dose of tramadol (22 mg/kg). Naloxone (0.5 mg/kg) partially counteracted the antiallodynic effect of tramadol (22 mg/kg). Conclusions These findings suggest the involvement of opioid and 5-HT_1A receptors in the antinociceptive effect of tramadol and support the idea that the combination of tramadol with compounds having 5-HT_1A antagonist properties could be a new strategy to improve tramadol-induced analgesia in neuropathic pain.     

慢性乙型病毒性肝炎病人血浆中LncRNA PVT1、微RNA-31-5p表达水平与炎症损伤程度的相关性分析

目的 探讨长链非编码RNA(LncRNA)人浆细胞瘤转化迁移基因1（）、微RNA-31-5p(miR-31-5p)在慢性乙型病毒性肝炎（CHB）病人血浆中的表达情况,并分析其与炎症损伤程度的关系。方法 选取东莞市人民医院2019年12月至2020年12月确诊的180例CHB病人为CHB组,所有病人均行肝穿刺活检,根据CHB病人炎症损伤程度分为G1组（66例）,G2组（58例）,G3组（41例）,G4组（15例）,根据肝纤维化程度进行分组,无明显肝纤维化（S0,S1）组（64例）,明显肝纤维化组（S2,S3）(78例),早期肝硬化（S4）组（38例）。同时选取55例健康者为对照组。收集CHB组和对照组的一般资料,分别检测两组血清肿瘤坏死因子-α(TNF-α)、白细胞介素（IL）-6、IL-1β、IL-10、超敏C反应蛋白（Hs-CRP）、丙氨酸氨基转移酶（ALT）、天冬氨酸转氨酶（AST）、谷氨酰基转移酶（GGT）等指标水平;采用实时荧光定量PCR法对血清中LncRNA PVT1、miR-31-5p表达水平进行检测,Pearson法分析LncRNA PVT1、miR-31-5p表达的相关...     

Fumonisin B1 and the kidney: Modes of action for renal tumor formation by fumonisin B1 in rodents

The mycotoxin fumonisin B₁ (FB₁) is an important contaminant of maize and maize-based products. In rodent toxicity studies, FB₁ was shown to be hepato- and nephrotoxic, and to induce renal tumors in rats when administered via the diet. Of particular note are the aggressive growth characteristics of FB₁-induced tumors with a high potential to metastasize. While genotoxicity does not appear to contribute to FB₁ carcinogenicity, it is well established that FB₁-mediated disruption of sphingolipid metabolism plays a key role in FB₁ toxicity. This review provides an overview on human dietary exposure to FB₁, FB₁ toxicity and carcinogenicity, and potential mechanisms involved in FB₁-mediated tumor formation, with a particular focus on cellular functions of sphingolipids and biological consequences of FB₁-mediated perturbation of sphingolipid metabolism.