鼠神经生长因子对坐骨神经痛大鼠背根神经节磷酸化p38MAPK表达的影响

目的:分析鼠神经生长因子对腰椎间盘突出致坐骨神经痛大鼠神经电生理及背根神经节（DRG）磷酸化p38丝裂原活化蛋白激酶（p38MAPK）表达的影响。方法:选取SPF级Wistar雄性大鼠90只，随机数字表法将其分为6组，正常组、模型组、阳性对照组、鼠神经生长因子低、中、高剂量组，每组各15只。除正常组外，其他各组大鼠制备腰椎间盘突出致坐骨神经痛模型。术后鼠神经生长因子低、中、高剂量组分别于硬膜外腔注射剂量为2.5 μL/100 g、5 μL/100 g及10 μL/100 g鼠神经生长因子，阳性对照组灌胃7.5 mg/kg的吲哚美辛药液，模型组和正常组大鼠注射等剂量生理盐水，1次/d，连续注射7 d。观察各组大鼠一般活动，机械缩足反应阈值（PWT）、热缩足反射潜伏期（PWL）、神经电生理、DRG内炎性因子、降钙素基因相关肽（CGRP）、P物质（SP）含量及磷酸化p38MAPK表达状况。结果:与正常组相比，给药3、7 d后模型组大鼠PWL、PWT下降；与模型组相比，给药3、7 d后阳性对照组、鼠神经生长因子中、高剂量组大鼠PWL、PWT上升（P＜0.05），且给药7 d效果优于给药3 d（P＜0.05）。与正常组相比，模型组大鼠DRG内SP、CGRP、TNF-α、IL-6及IL-1含量上升；与模型组相比，阳性对照组、鼠神经生长因子中、高剂量组大鼠DRG内SP、CFRP、TNF-α、IL-6及IL-1含量下降（P＜0.05）。与正常组相比，模型组大鼠DRG内p38MAPK表达上升；与模型组相比，阳性对照组、鼠神经生长因子中、高剂量组大鼠DRG内p38MAPK表达下降（P＜0.05）。结论:鼠神经生长因子可降低腰椎间盘突出致坐骨神经痛大鼠DRG神经元内磷酸化p38MAPK表达及炎性因子含量，改善神经传导功能。

Effects of rat nerve growth factor on the expression of phosphorylated p38MAPK in dorsal root ganglia of rats with sciatica

AIM: To analyze the effects of rat nerve growth factor on neuroelectrophysiology and expression of phosphorylated p38MAPK in dorsal root ganglion (DRG) in rats with sciatica caused by lumbar disc herniation. METHODS: 90 SPF-level Wistar male rats were randomly divided into 6 groups: normal group, model group, positive control group, low, medium and high dose groups of rat nerve growth factor, 15 in each group. Except the normal group, rats in other groups were prepared for sciatica caused by lumbar disc herniation. The low, medium and high doses groups were injected into the epidural space at 2.5 μL/100 g, 5 μL/100 g, 10 μL/100 g of rat nerve growth factor, respectively. The positive control group was given 7.5 mg/kg of indomethacin solution, the model group and the normal group were injected with the same dose of normal saline once a day for 7 days. The general activity, mechanical contraction response threshold (PWT), heat-shrinking foot reflex latency (PWL), neuroelectrophysiology, inflammatory factors in DRG, calcitonin gene-related peptide (CGRP), substance P (SP), and phosphorylation p38MAPK expression of the rats in each group were observed. RESULTS:Compared with the normal group, the PWL and PWT of the model group decreased after 3 and 7 days of administration. Compared with model group, the PWL and PWT of positive control group, middle and high dose group of rat nerve growth factor increased after 3 and 7 days of administration (P<0.05), and the effects of 7 days after administration was better than that of 3 days after administration (P<0.05). Compared with the normal group, the contents of SP, CGRP, TNF-a, IL-6 and IL-1 in DRG in the model group increased. Compared with the model group, the contents of SP, CFRP, TNF-a, IL-6 and IL-1 in DRG of rats in the positive control group and the middle and high dose groups of rat nerve growth factor decreased (P<0.05). Compared with the normal group, the expression of p38MAPK in the DRG of the model group increased; compared with the model group, the expression of p38MAPK in the DRG of the positive control group, the middle and high dose groups of the rat nerve growth factor decreased (P<0.05). CONCLUSION:Rat nerve growth factor can reduce the expression of phosphorylated p38MAPK and inflammatory factors in DRG of rats with sciatica caused by lumbar disc herniation, and improve nerve conduction function.