Colchicine effects on the expression of myelin basic protein in the sciatic nerve

J.B. AQUINO; M.F. CORONEL; J.M. PASQUINI; E.F. SOTO; M.J. VILLAR

Buenos Aires, Argentina

Congreso; International Society for Neurochemistry - American Society for Neurochemistry; 2001

International Society for Neurochemistry - American Society for Neurochemistry

Peripheral nerve injury was shown to alter the expression of MBP forming clusters of protein during Wallerian degeneration. These results suggest that normal expression of MBP could be dependent on the normal state of the nerve fibers. To test this hypothesis, we have analyzed changes in the expression of MBPs in Schwann cells after blocking the axonal transport in nerve fibers. Animals were anaesthetized and their right sciatic nerves exposed at the level of the thigh and injected with 1-3 ml of colchicine (5, 10, 20 mM). Sham animals with injection of saline into the sciatic nerve were also prepared. Animals were allowed to survive for 3-7 days and perfused. The ipsilateral and contralateral sciatic nerves were dissected out and processed for immunohistochemistry using MBP antibodies. The results showed a normal pattern of MBP-like immunoreactivity (LI) in the sciatic nerve of sham operated animals as well as in the contralateral nerves of colchicine-injected rats.  The sciatic nerves injected with colchicine showed a pattern of MBP-LI that resembled that previously observed after peripheral nerve injury. The immunostaining showed a reorganization in clusters distally to the site of injection. These results give further support to the idea that the normal expression of MBP content in Schwann cells may depend on a trophic signal originated in nerve fibers. Several experiments are currently being performed to analyze the nature of that trophic signal