2001 Fiscal Year Final Research Report Summary

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

Research Project

Project/Area Number	12671411
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Orthopaedic surgery
Research Institution	KYOTO UNIVERSITY
Principal Investigator	NAKAGAWA Yasuaki Kyoto University Faculty of Medicine, Lecturer, 医学研究科, 講師 (90293860)
Co-Investigator(Kenkyū-buntansha)	NAKAMURA Takashi Kyoto University Faculty of Medicine, professor, 医学研究科, 教授 (10201675)
Project Period (FY)	2000 – 2001
Keywords	Sciatic nerve / transection / suture / Wallerian degeneration / m-calpain
Research Abstract	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.