Objective: To observe the effects of electroacupuncture (EA) combined with acellular nerve allograft (ANA) on the morphological structure of spinal ganglion cells and the protein expressions of nerve growth factor (NGF) and phosphorylated protein kinase B (p-Akt) in rats with sciatic nerve injury (SNI), so as to explore the protective mechanism of EA combined with ANA on spinal ganglia.
Methods: SPF male SD rats were randomly divided into normal, model, single ANA bridging (bridging) and EA + ANA (combination) groups， with 10 rats in each group. The SNI rat model was established by right sciatic nerve transection. Rats in the bridging group were bridged with ANA to the two broken ends of injured sciatic nerves. Rats in the combination group were treated with EA at "Yanglingquan" (GB34) and "Huantiao" (GB30) 2 d after ANA bridging, with dilatational wave, frequency of 1 Hz/20 Hz, intensity of 1 mA, 15 min/d, 7 d as a course of treatment for 4 consecutive courses. Sciatic function index (SFI) was observed by footprint test. Wet weight ratio of tibialis anterior muscle was calculated after weighing. Morphology of rat spinal ganglion cells was observed after Nissl staining. The protein expressions of NGF and p-Akt were detected by immunofluorescence and Western blot.
Results: Compared with the normal group, the SFI and wet weight ratio of tibialis anterior muscle were significantly decreased (P<0.05), the number of Nissl bodies in spinal ganglion cells was significantly reduced (P<0.05) with dissolution and incomplete structure， the protein expressions of NGF and p-Akt in ganglion cells were significantly decreased (P<0.05) in the model group. Following the interventions and in comparison with the model group, the SFI and the wet weight ratio of tibialis anterior muscle were significantly increased (P<0.05), the damage of Nissl bodies in ganglion cells was reduced and the number was obviously increased (P<0.05), and the protein expressions of NGF and p-Akt in ganglion cells were significantly increased (P<0.05) in the bridging and combination groups. Compared with the bridging group, the SFI and the wet weight ratio of tibialis anterior muscle were increased (P<0.05), the morphology of Nissl bodies in ganglion cells was more regular and the number was increased (P<0.05), the protein expressions of NGF and p-Akt in spinal ganglion cells were significantly increased (P<0.05) in the combination group.
Conclusion: EA combined with ANA can improve the SFI and the wet weight ratio of tibialis anterior muscle in SNI rats, improve the morphology and structure of Nissl bodies in spinal ganglion cells, and increase the protein expressions of NGF and p-Akt in spinal ganglion, so as to play a protective role on spinal ganglia.
目的：观察电针联合脱细胞异体神经移植物(ANA)对坐骨神经损伤(SNI)大鼠脊神经节细胞形态结构及神经生长因子(NGF)和磷酸化蛋白激酶B(p-Akt)蛋白表达的影响，探讨电针联合ANA对脊神经节的保护机制。方法：将SPF级雄性SD大鼠随机分为正常组、模型组、单纯ANA桥接组(桥接组)和电针联合ANA组(联合组)，每组10只。采用右侧坐骨神经离断法制备SNI大鼠模型。桥接组将ANA桥接于损伤坐骨神经的两断端处。联合组在ANA桥接术后2 d予患侧“阳陵泉”“环跳”电针治疗，疏密波，频率1 Hz/20 Hz，强度1 mA，15 min/d，7 d为1个疗程，连续治疗4个疗程。足迹实验观察各组大鼠坐骨神经功能指数(SFI)；计算大鼠胫前肌湿重比率；尼氏染色法观察大鼠腰4-6段右侧脊神经节细胞的形态结构；免疫荧光法和Western blot法检测大鼠脊神经节中NGF和p-Akt蛋白的表达。结果：与正常组比较，模型组大鼠SFI和胫前肌湿重比率显著降低(P<0.05)；脊神经节细胞中尼氏体溶解，结构不完整，数量减少(P<0.05)，NGF和p-Akt蛋白表达量显著降低(P<0.05)。与模型组比较，桥接组和联合组大鼠SFI和胫前肌湿重比率显著升高(P<0.05)；脊神经节细胞中尼氏体损伤减弱且数量增加(P<0.05)，NGF和p-Akt蛋白表达量显著升高(P<0.05)。与桥接组比较，联合组大鼠SFI和胫前肌湿重比率显著升高(P<0.05)；脊神经节细胞中尼氏体形态较规则且数量增加(P<0.05)，NGF和p-Akt蛋白表达量显著升高(P<0.05)。结论：电针联合ANA治疗可提高大鼠SFI和胫前肌湿重比率，改善脊神经节细胞的形态结构，其机制可能与增加脊神经节中NGF和p-Akt蛋白的表达，从而发挥对脊神经节的保护作用有关。.
Keywords: Acellular nerve allografts; Electroacupuncture; Nerve growth factor; Phosphorylated protein kinase B; Sciatic nerve injury; Spinal ganglion.