艾灸对原发性坐骨神经痛大鼠坐骨神经干及脊髓腹角GAP-43表达的影响及其神经修复作用

目的:观察艾灸"环跳"穴对原发性坐骨神经痛大鼠坐骨神经干和脊髓腹角(L₄~L₆)生长相关蛋白-43(GAP-43)表达的影响,探讨艾灸改善原发性坐骨神经痛的作用机制。方法:将48只健康雄性SD大鼠随机分为正常组、假手术组、模型组和艾灸组,每组12只。模型组和艾灸组大鼠采用坐骨神经慢性压迫性损伤(CCI)术建立原发性坐骨神经痛大鼠模型。实验第8天,艾灸组大鼠于患侧"环跳"穴行温和灸5~10 min,每日1次,连续14 d。分别于实验第1、7、14、21天测定各组大鼠坐骨神经功能指数(SFI)。实验第21天,HE染色法观察大鼠脊髓腹角和坐骨神经干形态;免疫组织化学法和实时荧光定量PCR法检测大鼠脊髓和坐骨神经干GAP-43蛋白和mRNA的表达。结果:假手术组大鼠实验第7、14、21天SFI与正常组比较差异无统计学意义(P>0.05);与假手术组比较,模型组大鼠实验第7、14、21天SFI降低(P<0.01);与模型组比较,艾灸组大鼠实验第14、21天SFI升高(P<0.01)。正常组和假手术组大鼠脊髓腹角内神经元细胞排列整齐,尼氏体分布均匀,坐骨神经轴突髓鞘结构清晰可见;模型组大鼠脊髓腹角内可见神经元细胞变形和破溃,尼氏体数量少,坐骨神经轴突脱髓鞘改变;艾灸组大鼠脊髓腹角内可见神经元细胞排列较规则,尼氏体增多,坐骨神经轴突部分脱髓鞘改变。与正常组比较,假手术组大鼠坐骨神经干GAP-43 mRNA和蛋白表达、脊髓腹角GAP-43蛋白表达升高(P<0.01);与假手术组比较,模型组大鼠脊髓腹角和坐骨神经干GAP-43 mRNA和蛋白表达升高(P<0.01);与模型组比较,艾灸组大鼠脊髓腹角和坐骨神经干中GAP-43 mRNA和GAP-43蛋白表达升高(P<0.01)。结论:艾灸"环跳"穴可改善原发性坐骨神经痛大鼠坐骨神经功能,可能与上调脊髓腹角和坐骨神经干GAP-43表达,增强坐骨神经的自我修复能力有关。

Effect of moxibustion on expression of GAP-43 in sciatic nerve trunk and ventral horn of spinal cord of rats with primary sciatica and its nerve repair function

Objective To observe the effect of moxibustion at "Huantiao"(GB 30) on the expression of growth-associated protein-43(GAP-43) in the sciatic nerve trunk and ventral horn of spinal cord(L₄-L₆) in rats with primary sciatica, and to explore the mechanism of moxibustion in improving primary sciatica. Methods A total of 48 healthy male SD rats were randomly divided into a normal group, a sham operation group, a model group and a moxibustion group, 12 rats in each group. The rat model of primary sciatic pain was established by chronic constriction injury(CCI) of the sciatic nerve in the model group and the moxibustion group. On the 8 th day of the experiment, moxibustion was adopted at "Huantiao"(GB 30) in the moxibustion group for 5-10 min, once a day for 14 consecutive days. Sciatic nerve function index(SFI) was measured and compared in each group at day 1, 7, 14 and 21. On the 21 st day of the experiment, HE staining was used to observe the morphology of ventral horn of rat spinal cord and sciatic nerve trunk. Immunohistochemical method and real-time PCR were used to detect mRNA and protein expressions of GAP-43 in the spinal cord and sciatic nerve trunk of rats. Results On day 7, 14 and 21, there was no statistical difference in SFI between the sham operation group and the normal group(P>0.05);compared with the sham operation group on day 7, 14 and 21, the SFI of the model group was reduced(P<0.01);compared with the model group on day 14 and 21, SFI in the moxibustion group was increased(P<0.01). In the normal group and the sham operation group, neuronal cells were in order in the ventral horn of the spinal cord, nissl bodies were spaced regularly, the myelin sheath structure of sciatic nerve axon was clearly visible. In the model group, neuronal cells were deformed and ruptured in the ventral horn of the spinal cord, the number of nissl bodies was less, and the demyelination of sciatic axons appeared. In the moxibustion group, neuronal cells were found in the ventral horn of spinal cord, and the number of nissl bodies was increased, and less demyelinating changes of axons appeared in sciatic nerve. Compared with the normal group, the expressions of GAP-43 mRNA and GAP-43 protein in the sciatic nerve trunk and GAP-43 protein in the ventral horn of spinal cord were increased in the sham operation group(P<0.01). Compared with the sham operation group, the expression of GAP-43 mRNA and GAP-43 protein in the spinal cord and sciatic nerve trunk of rats in the model group was increased. Compared with the model group, the expression of GAP-43 mRNA and GAP-43 protein in the spinal cord and sciatic nerve trunk of rats in the moxibustion group was increased(P<0.01). Conclusion Moxibustion at "Huantiao"(GB 30) could improve the sciatic nerve function in rats with primary sciatica and its mechanism may be related to improving the expression of GAP-43 and enhancing the self-repair ability of the sciatic nerve after injury.