Expression of N-cadherin by skeletal muscle in the degeneration and the degeneration/regeneration processes after nerve injury.

We investigated the expression of N-cadherin by skeletal muscle during the degeneration and degeneration/regeneration processes using the rat sciatic nerve and gastrocnemius muscle model. The right sciatic nerve was exposed in the mid-thigh region, and the nerve was transsected with small scissors. After then, nerve was sutured (sutured group), or both edges of the resected nerve were turned and sutured to the muscle of each side (unsutured group). At various periods up to 24 weeks after the operation the middle portion of the gastrocnemius muscle of the treated hindlimbs was removed. Expression of N-cadherin was detected by western blot analysis and immunofluorescent staining with an anti N-cadherin antibody. In the both groups, the degree of expression had already increased by the end of the first postoperative week, but there were no significant differences between the first and second postoperative weeks between the two groups. However, the values recorded at the fourth, sixth, ninth, and twelfth postoperative weeks were significantly higher in the unsutured group than in the sutured group. Immunofluorescent staining was present around the muscular membrane in all specimens including the control. These results indicated that there was a difference in the kinetics of expression of N-cadherin in skeletal muscle between the degeneration and degeneration/regeneration processes of the muscle after injury to the nerve. It was also clear that N-cadherin has a role at the surface of the muscle cell in skeletal muscle, not in the satellite and inflammatory cells, in both groups.