大鼠脊髓挫伤后脊髓和骨骼肌中GAP-43的表达变化

Changes of GAP-43 Expression in the Spinal Cord and Skeletal Muscles in Adult Rats Subjected to Spinal Cord Contusion

目的观测大鼠脊髓挫伤后损伤位点尾侧和骨骼肌中GAP-43的含量变化,探讨其在脊髓损伤修复中的作用及与脊髓可塑性的关系.方法SD成年大鼠40只,分为正常组和脊髓挫伤组,分别取材脊髓和腓肠肌,用免疫组化了解GAP-43的原位分布和Western Blot检测GAP-43的含量;各组大鼠在存活期间均行后肢BBB运动功能评分.结果各组大鼠脊髓腹角少量神经元和腓肠肌细胞内均可观察到GAP-43阳性反应物;大鼠脊髓挫伤后3d,脊髓及骨骼肌中的GAP-43表达均开始增加,脊髓于14d达高峰,而骨骼肌21d达到高峰;BBB运动功能评分从7d起逐步恢复,21d接近正常.结论大鼠脊髓损伤后,脊髓和骨骼肌中GAP-43含量变化的趋势与下肢运动功能的恢复较一致,提示GAP-43表达增加与脊髓挫伤后的可塑性有关.

Objective To explore changes of the GAP-43 in the skeletal muscle and the spinal cord in the tail side after spinal cord contusion in rat, and to study relationship between plasticity and GAP-43 in spinal cord injury. Methods 40 adult SD rats were divided into normal and spinal cord contusion groups. GAP-43 in situ distribution was measured by immunohistochemical staining and GAP-43 levels were detected by Western Blot with the spinal cord and the gastrocnemius muscle. BBB motor function was scored for normal and contusion groups in survived rats. Results Each group some amount of the ventral horn neurons in spinal cord and gastrocnemius ceils were observed GAP-43 positive objection. GAP-43 expression in the spinal cord and skeletal muscle from 3rd day after spinal cord contusion began to increase. GAP-43 expression reached the peak at 14th day in the spinal cord, but the peak of GAP-43 expression at 21-day in the skeletal muscle. BBB motor function resumed gradually from 7d to close normal at 21d. Conclusions The change of GAP-43 content in spinal cord and skeletal muscle is consistent with the function recovery of lower limb after spinal cord injury in rats. This indicates that the increased expression of GAP-43 is related with the plasticity after spinal cord injury.