GDNF及BDNF对受损运动神经元的长期修复

LONG TERM RESTORATION OF GDNF AND BDNF ON LESIONED MOTONEURONS

为了研究胶质细胞源神经营养因子（ＧＤＮＦ） 及脑源神经营养因子（ＢＤＮＦ） 对切断轴突的新生运动神经元的长期维持存活及促进神经再生的作用， 我们选用出生时单侧切断坐骨神经的雏鸡模型， 用裸ＤＮＡ 转染方法， 在损伤神经附近的肌肉中转染ＧＤＮＦ ｃＤＮＡ 和ＢＤＮＦ ｃＤＮＡ 的真核表达载体，观察在体表达的神经营养因子对损伤的修复作用。结果显示，在体表达的ＧＤＮＦ 在８ 周内能使切断坐骨神经的腰脊髓运动神经元近９０ ％ 维持存活。切断的坐骨神经从断端向远体端再生，最长再生达９ ．５ｍ ｍ 。表达两个因子比单独表达ＧＤＮＦ 对运动神经元的存活无显著性差异。而两个因子协同作用对坐骨神经的再生更为有效，坐骨神经再生最长的可达１５ ．４ｍ ｍ 。

To study the long-term effects of GDNF and BDNF on survival of neonatal lesioned motoneurons and regeneration of cut sciatic nerve, the chicken model with unilateral sciatic nerve axotomy at 3 hour posthatching was treated with in vivo expressed GDNF and BDNF in muscles around cut side by transfecting eukaryotic expression vectors of GDNF and BDNF cDNA into the muscles, The restoration effects were observed within experimental period (8 weeks). In vivo expressed GDNF could prevent lesioned motoneurons from death. The survival of lesioned lumbar motoneurons during experiments was about 90% and maximal regeneration length of sectioned nerve from proximal end to distal end was 9.5mm. Co-expression of GDNF and BDNF cDNA made no significant difference from expression of GDNF in lesioned motoneuron survival but was significantly different in lesioned nerve regeneration. The longest regeneration of sciatic nerve for co-expression of two factors was 15.4mm.