Change of m-calpain in transected and sutured sciatic nerve of rat

沃勒氏变性引起横断周围神经的神经丝变性。据报道，m-calpain存在于大鼠坐骨神经中，并可能在Wallerian再生过程中发挥重要作用。取8周龄雄性Wister大鼠。右坐骨神经在右髋关节的后下段被切断，截断的末梢被收回以防止再生。显微镜下用10-0尼龙单丝缝合截断的左侧坐骨神经。坐骨神经治疗（仅切除或缝合）后，于次日（第1天）、第3天、下一周（第1周）、第2周、第4周、第6周、第8周、第12周、第16周取近端8 mm和远端8 mm处的神经末梢（仅切除或缝合）。每个样品分为两个等分，第一个等分进行蛋白质检测，第二个等分进行Western blot分析。每个样品通过蛋白质浓度归一化。结果表明，缝合和横断的坐骨神经近端和远端m-calpain含量随时间推移而增加。但在缝合的神经中，8周后近端m-calpain量减少，12周后远端m-calpain量有减少的趋势。而在横断的神经中，则看不到这种倾向。鉴于许多关于calpain抑制剂作为神经保护剂的报道，在Wallerian退变过程中，早期calpain发挥积极作用，但在晚期，calpain可能是周围神经正常再生的抑制剂。

Wallerian degeneration induces neurofilament degeneration in transected peripheral nerve. It has been reported that m-calpain exists in rat sciatic nerve and may play a significant role during Wallerian regeneration. Eight-week-old male Wister rats were obtained. The right sciatic nerve was cut sharply at the postero-inferior portion of right hip joint and the transected ends were retracted to prevent regeneration. The left sciatic nerve which was transected was sutured with 10-0 nylon monofilament with microscope. After sciatic nerves were treated (transected only or sutured), on next day (first day), third day, next week (first week), second week, fourth week, sixth weed, eighth week, twelfth week and sixteenth week, the nerve ends (transected only or sutured) were obtained at proximal 8 mm and distal 8 mm. Each sample was divided into two aliquots, the first aliquot was assayed for protein, the second aliquot was subjected to Western blot analysis. Each sample was normalized by the concentration of protein. In order to quantity the amount of m-calpain at proximal and distal ends of sutured and transected sciatic nerves increased in time course experiments. But in the sutured nerves, the amount of m-calpain at proximal ends decreased after eighth week, and at distal ends tended to diminish after twelfth week. In contrast, in the transected nerves, the tendency could not be seen. In view of many reports of calpain inhibitors as neuroprotectors, during Wallerian degeneration, in early stage, calpain play a positive role, but in late stage, calpain may be an inhibitor of normal regeneration of peripheral nerves.