摘要
目的：观察Rho A相关细胞骨架调控信号通路在慢性坐骨神经结扎（chronic sciatic nerve constriction injury,CCI）神经病理性疼痛大鼠背根神经节激活及辛伐他汀（simvastatin）鞘内给药对该通路影响。方法：42只质量180~200 g SD雄性大鼠随机分为5组：Na？ve组（n=6）、Sham组（n=6）、CCI组（n=18）、Simvastatin组（n=6）及Rho激酶（Rho kinase,ROCK）抑制剂Y-27632组（n=6）。对大鼠行鞘内置管,于造模后7天结扎CCI组、Simvastatin组及Y-27632组大鼠单侧坐骨神经构建CCI模型,术后Simvastatin组每天鞘内注射10μl辛伐他汀（10μg/μl）,Y-27632组每天鞘内注射12μl Y-27632（4 mg/ml）,Na？ve组、Sham组、CCI组术后每天鞘内注射生理盐水10μl,连续注射7天。于CCI建模后1、3、7、14天进行动物行为学评估,观察大鼠对机械和热刺激的反应。于建模后第14天处死大鼠,取手术侧L4~6背根神经节（dorsal root ganglion,DRG）,并进行实时定量PCR观察RhoA、ROCK的m RNA表达变化,免疫荧光观察Rho A蛋白在DRG伤害性神经元中的分布及改变,以及免疫荧光强度随建模时间梯度增加,Western blot检测通路中主要因子RhoA、LIMK和cofilin蛋白水平表达的改变。结果：1 Simvastatin组大鼠给予辛伐他汀后第3天起缩足反射热辐射潜伏期、缩足反射机械刺激阈值明显高于CCI组,差异具有统计学意义（P〈0.05）;ROCK抑制剂Y-27632组大鼠缩足反射热辐射潜伏期、缩足反射机械刺激阈值给药后3天起较CCI组明显提高,差异具有统计学意义（P〈0.05）。2 CCI组大鼠DRG中Rho A、ROCK m RNA于术后第7天起表达显著增加（P〈0.05）;Rho A蛋白在背根神经节神经元中表达,CCI术后14天Rho A免疫荧光强度与Na？ve组比显著增高（P〈0.05）。3鞘内注射辛伐他汀能显著抑制通路主要因子Rho A、p-LIMK、p-cofilin的表达（P〈0.05）。结论：大鼠CCI慢性神经病理性疼痛存在Rho A/LIMK/cofilin通路的激活,辛伐他汀鞘内注射可抑制该通路的活化,为治疗神经病理性疼痛提供新的靶点。
Objective： To investigate the role of intrathecal simvastatin administration on inhibiting Rho Arelated pathway and its therapeutic effect on neuropathic pain in rats. Methods： Forty-two SD rats weighing 180~200 g were randomly divided into Na？ve group（n = 6）, Sham group（n = 6）, CCI group（n = 18）, Simvastatin group（n = 6） and Rho kinase inhibitor Y-27632 group（n = 6）. Rats in each group were placed intrathecal catheter. Seven days later, CCI group, the rats in Simvastatin group and Rho kinase inhibitor Y-27632 group received chronic sciatic nerve constriction injury（CCI）. Simvastatin（10 μl, 10 μg/μl）, Y-27632（12μl, 4 mg/m L）, or the same volume of normal saline were applied through the intrathecal catheter once daily after CCI for 7 consecutive days. The paw withdrawal mechanical threshold（PWMT） and paw withdrawal thermal latency（PWTL） were used to evaluate the behavioral changes on days 1, 3, 7 and 14 after surgery. L4-6 dorsal root ganglions were removed on postoperative day 14, followed by RT-q PCR to measure the m RNA expression of Rho A and ROCK2, and immunofluorescence and Western blot to evaluate the protein expression of Rho A, phosphorylated-LIMK and phosphorylated-cofilin. Results： Administration of simvastatin significantly attenuated heat hyperalgesia and mechanical allodynia at each time point examined compared with normal saline administration in CCI group（P 0.05）. Likewise, when Y-27632 was administered intrathecally, the pain-related behavior of the CCI group was significantly reduced compared with that of the CCI group（P 0.05）. Meanwhile, the expression of Rho A increased significantlg on day 7 after surgery in CCI group tested by Western Blot, immunofluorescence and RT-q PCR（P 0.05）. After the administration of simvastatin, the pain behaviors of the CCI rats alleviated significantly（P 0.05）. Simvastatin also inhibited the m RNA level of Rho A and ROCK, the protein level of Rho A, phosphorylated-LIMK, and phosphorylated-cofilin on postoperative day 14（P 0.05）. Conclusions： Simvastatin can attenuate neuropathic pain of CCI rats through inhibiting Rho A/LIMK/cofilin pathway. Therefore, simvastatin may be a novel target for the treatement of neuropathic pain.
出处
《中国疼痛医学杂志》
CAS
CSCD
2016年第7期493-500,共8页
Chinese Journal of Pain Medicine
