不同年龄大鼠外周神经损伤后CNTF、CNTFRα的蛋白表达及MBP含量变化

Expression of CNTFRα and CNTF Protein, and Change in MBP Content in Spinal cord and Sciatic Nerve Ages Following Injury of Sciatic Nerve in Rats at Different Age

目的探讨髓鞘碱性蛋白(myelinbasicprotein,MBP)和睫状神经营养因子(ciliaryneuotrophicfactor,CNTF)在周围神经损伤及再生修复过程中的影响。方法将不同年龄组大鼠采用损伤后外周神经小室再生模型,用酶联免疫法测定坐骨神经中MBP含量,用免疫组化和Westernblotting检测CNTF及CNTFRα在坐骨神经和脊髓中的表达。结果各年龄组伤前脊髓中有CNTFRα表达,CNTF较少表达;周围神经中CNTF主要分布在雪旺氏细胞(SCs)中,CNTFRα极少表达。各年龄组伤后损伤侧脊髓CNTF、CNTFRα,伤侧神经CNTFRα表达较伤前显著升高(P<0.05～0.01),4周达最高峰;伤侧近、远端神经中CNTF伤后1d～1周表达较伤前减低(P<0.05),2周后开始升高,4周达高峰。其中幼年变化最大,成年次之,老年最弱。MBP的变化与神经CNTF的变化具有一致性,且远端高于近端。结论坐骨神经再生过程中大鼠神经、脊髓CNTF及CNTFRα表达的变化与神经再生髓鞘化的进程密切相关,不同年龄大鼠对CNTF的依赖性不同,MBP的变化与CNTF具有相关性。

Objective To investigate the effects of myelin basic protein (MBP) and ciliary neuotrophic factor (CNTF) on the injury and regeneration of sciatic nerve in rats. Methods Nerve regeneration chamber model was applied to the rats with sciatic nerve injury in different ages group. The MBP content in sciatic nerve was measured by ELISA. The expressions of CNTFRα and CNTF in the spinal cord tissue and sciatic nerve in rats following transection of the sciatic nerve were detected by both immunohistochemistry and western blotting. Results There were expression of CNTFRα and less expression of CNTF in the spinal cord before the injury in the rats of different ages. There were expression of CNTF in Schwann cells and less expression of CNTFRα in the sciatic nerve before injury in the rats of different ages. The expressions of CNTF and CNTFRα in the injured side of spinal cord and the expression of CNTFRα in the injured side of sciatic nerve increased after the injury in the rats of different ages as compared with before the injury, reaching their peak 4 week after the injury (P<0.05 or 0.01). The expression of CNTF in both the distal and the proximal nerve decreased 1 day to 1 week after injury, increased at 2 weeks after injury again and reached their peak 4 weeks (P<0.05 or 0.01). The above-metioned change in the CNFRα expressions in the young rats were more significant than that in adult or old rats. The change in MBP content was similar to that in the CNTF. The change in MBP content in the distal nerve was more significant than that in the proximal nerve. Conclusions The results suggest that the changes in CNTF and CNTFRα are correlated with the process of nerve regeneration, which in the different ages rats is differently dependment on CNTFR. The change in MBP content of the sciatic nerve after injury is related to CNTF.