The difference in E-cadherin expression between nonvascularized and vascularized nerve grafts: Study in the rat sciatic nerve model

Background. We investigated the expression of E-cadherin during nerve regen eration after nonvascularized and vascularized nerve grafts. Materials and methods. We used the rat sciatic nerve model. E-cadherin expr ession was detected by Western blot analysis and immunofluorescent staining with anti E-cadherin monoclonal antibody. The level of E-cadherin expressi on was calculated as the amount relative to that of E-cadherin expression o f normal control nerve. Furthermore, repair of the neural tissue structure was examined by toluidine blue staining. Results. In both cases, the level of E-cadherin expression decreased at fir st, and then gradually increased. The maximum level was 1.61 +/- 0.066-fold in the nonvascularized nerve graft and 2.254 +/- 0.071-fold in the vascula rized nerve graft. From the 1 st to the 16th post-operative weeks, the leve l of E-cadherin expression in the vascularized nerve graft was significantl y higher than that in the nonvascularized nerve graft. In the immunofluores cent staining, E-cadherin expression was almost negative or decreased immed iately after the operation, but the degree of expression was gradually incr eased in Schwann cells. The degree of E-cadherin expression in the vascular ized nerve graft was greater than that in the nonvascularized nerve graft. In toluidine blue staining, the velocity of. tissue repair was more rapid i n the vascularized nerve graft than in the nonvascularized graft. Conclusion. These results demonstrate that the E-cadherin expression of gra fted nerve was increased during the nerve regeneration, and the expression was mainly observed in Schwann cells. Because the level of E-cadherin expre ssion was significantly higher in the vascularized nerve graft than in the nonvascularized nerve graft, the level of E-cadherin expression may affect the rapidity of nerve regeneration. (C) 2001 Academic Press.