P 0 and Myelin Basic Protein-Like Immunoreactivities following Ligation of the Sciatic Nerve in the Rat*

In this work we analyzed variations in the expression of MBPs and P0 in ligated sciatic nerves of young and adult rats at 3, 7, and 14 days postligation (PL), by immunohistochemistry and SDS-PAGE of isolated myelin. A protein redistribution was seen in the distal stump of ligated nerves with the appearance of immunoreactive clusters. Using the KS400 image analyzer, immunostained area values were obtained from the different nerves dissected. In adult rats, there was an increase of the immunostained area for MBP from 3 to 7 days PL, coincident with a reorganization of the marker in clusters, followed by a marked decrease at 14 days. P0 immunolabeling gave similar results without, however, a decrease of the immunostained area at the longer survival time tested. Young animals showed an acceleration in the process of protein redistribution and digestion within ligated nerves, which followed a similar pattern as that of adult animals. Analysis by electrophoresis showed a marked decrease in P0 and MBP at 7 days PL in young rats and 14 days PL in adult rats. The functional significance of protein clustering within myelin in injured nerves deserves further analysis.