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背景:外周神经损伤后发生瓦勒变性,其机制复杂,从免疫学角度对其进行调控可以影响神经早期修复效果。目的:分析特异性拮抗Toll样受体4(TLR4)对于大鼠坐骨神经损伤早期瓦勒变性及轴突再生的影响。方法:将50只Wistar大鼠随机分成3组:处理组及模型组横断大鼠右侧坐骨神经后,行神经外膜端端吻合;假手术组仅游离出坐骨神经,然后关闭切口。术前1 h及术后7 d处理组大鼠每天尾静脉注射0.15 mg/kg Toll样受体4拮抗剂TAK-242,模型组及假手术组大鼠尾静脉注射同等体积生理盐水。于术后24 h、3 d、4 d和7d取术侧坐骨神经。结果与结论:(1)实时定量PCR显示,与假手术组相比,术后24 h模型组白细胞介素1βmR NA和单核细胞趋化蛋白模型组相比,术后1 mR NA的表达均明显升高(P<0.001,P<0.001),与24 h处理组白细胞介素1βmR NA和单核细胞趋化蛋白1 mR NA的表达明显降低(P<0.001,P<0.001);(2)免疫荧光可见,与模型组相比,术后3 d处理组中CD68+细胞和iba1+细胞表达均显著下调(P<0.01,P<0.05);(3)固兰染色可见,在术后7 d,模型组和处理组坐骨神经断端均出现脱髓鞘反应,但与模型组相比,处理组神经断端髓鞘碎片清除率明显降低(P<0.05);(4)苏木精-伊红染色可见,在术后7 d,模型组坐骨神经断端较多炎性细胞浸润,许旺细胞增殖活跃,神经纤维大量再生通过吻合口,断端修复正常,处理组神经断端炎性细胞较少,纤维组织增生较少,吻合口有缝隙,断端修复能力减弱;(5)免疫组织化学可见,与模型组相比,术后4 d处理组中生长相关蛋白43蛋白表达均显著下调(P<0.05);(6)坐骨神经功能指数显示,与模型组相比,处理组大鼠在术后20,30和40 d同期比较明显降低,差异有显著性意义(P<0.05)。(7)结果证实,Toll样受体4拮抗剂导致大鼠坐骨周围神经损伤早期再生延迟,其机制可能是抑制了瓦勒变性过程中的的Toll样受体4信号通路。
Background: Wale degeneration occurs after peripheral nerve injury and its mechanism is complex. To regulate it from the perspective of immunology can affect the early repair of nerve. Objective: To investigate the effects of specific antagonism of Toll-like receptor 4 (TLR4) on Wallerian degeneration and axon regeneration at the early stage of sciatic nerve injury in rats. Methods: Fifty Wistar rats were randomly divided into three groups. The rats in the treatment group and the model group were transected to the right sciatic nerve of rats and the anastomosis of the epineurium was performed. In the sham operation group, only the sciatic nerve was free, and the incision was closed. At 1 h before operation and 7 days after operation, the tail vein of the treated group received 0.15 mg / kg Toll-like receptor 4 antagonist TAK-242. The rats in the model group and the sham operation group received the tail vein injection of the same volume of normal saline. The operative side sciatic nerve was taken at 24 h, 3 d, 4 d and 7 d after operation. RESULTS AND CONCLUSION: (1) Real-time quantitative PCR showed that compared with sham-operation group, the expression of IL-1β mRNA in the model group at 24 h after operation was significantly lower than that in monocyte chemoattractant protein model group (P <0.001, P <0.001). Compared with 24 h treatment group, the expression of interleukin 1βmRNA and monocyte chemoattractant protein 1 mR NA were significantly decreased (P <0.001, P <0.001) Immunofluorescence showed that compared with the model group, the expression of CD68 + cells and iba1 + cells in the 3-day post-operation group were significantly decreased (P <0.01, P <0.05); (3) Compared with the model group, the demyelination of the sciatic nerve in the model group and the treated group showed demyelination, but the clearance rate of the demyelinated myelin debris in the treated group was significantly lower than that in the model group (P <0.05); (4) Hematoxylin-eosin staining It can be seen that on the 7th day after operation, more inflammatory cells were infiltrated into the sciatic nerve in the model group, the proliferation of Schwann cells was active, the nerve fibers were regenerated through the anastomoses in a large amount, the broken ends were repaired normally, (5) Immunohistochemistry showed that compared with the model group, the expression of growth-associated protein 4 in the 4-day post-operation group was significantly lower than that in the untreated group (P <0.05). (6) Sciatic nerve function index showed that compared with the model group, the rats in the treated group were significantly reduced at the same period of 20, 30 and 40 days after operation, with significant difference (P < P <0.05). (7) The results confirmed that Toll-like receptor 4 antagonists lead to early post-sciatic nerve injury in rats delayed regeneration, the mechanism may be inhibited during the Wale degeneration Toll-like receptor 4 signaling pathway.