|Budget Amount *help
¥2,000,000 (Direct Cost : ¥2,000,000)
Fiscal Year 1999 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1998 : ¥1,500,000 (Direct Cost : ¥1,500,000)
Object : The mechanism of collateral spouting axons from an uninjured donor nerve after end-to-side nerve repair was investigated in motor nerves of rats, with special reference to neurotrophins related to nerve regeneration. In addition, the growth cone formation which is formed at the tip of the regenerating nerve was examined.
Methods : The transected medial gastrocnemius nerve (MGN) was transferred to the side of intact lateral gastrocnemius nerve (LGN) using a Y-shaped silicone tube. No epineurial window, suture damage or perineurial slit was made in the LGN at the site of coaptation. Other nerves in the leg were transected and ligated. At 3, 7 or 14 days later, the MGN with LGN was transected around the coaptation site, and was stained immunohistologically. In the results, the NT-3 and TrK C (receptor of NT-3) expressions were most significantly observed at 3 days postoperatively around the site of coaptation. BDNF was weakly detected at the coaptation site 3 days post-operatively. TrK B (receptor of BDNF) was not significantly detected in the specimens. Growth-associated protein 43 (GAP-43) which is a marker of growth cone formation, was observed at the site of coaptation in the LGN at 7 days postoperatively, and also in the MGN at 14 days at the site of coaptation.
Conclusions : We concluded that motor nerve regeneration due to collateral spouting of axons after end-to-side nerve repair is possible. In this situation, we showed the involvement of at least one neurotrophin, NT-3, in the process of collateral sprouting of motor nerves.