Oligodendrocyte maturation is regulated by thyroid hormones during remyelination.

SILVESTROFF, L., FRANCO, P., SOTO, E. AND PASQUINI, J.

Chichen Itza, Me;xico

Conferencia; ISN- Myelin Satellite Conference; 2007

ISN

Wistar rats were fed a diet containing 0.6% cuprizone (CPZ) for two weeks to induce demyelination. After CPZ withdrawal rats were subcutaneously injected on days 35, 37 and 39 with T3 or saline solution. Histological studies showed an increased remyelination in the corpus callosum (CC) of T3 treated rats when compared to control ones. Immunohistochemical studies were used to analyze develomental parameters of the oligodendroglial cell (OLGc) population after T3 treatment. Our results showed increased numbers of O4, MBP, PLP, RIP, CC1 and transferrin (Tf) positive cells within the CC of T3 treated rats in comparison to control. A2B5+ cells decreased in T3 treated animals with no changes in Shh+ and NG2+ cells. T3 receptors were weakly expressed in the CC, however TRá is expressed in the ventricle wall of both experimental situations and TRâ is activated in the periventricular area of T3 treated rats. In the subventricular zone (SVZ)  of T3-treated rats we noticed a decrease in nestin+ cells coincident with a downregulation of Id4 expression. NG2 expressing cells migrated further away from the ventricle wall in T3 treated animals. T3 also induced Olig1 and Shh expression in the ventricle wall. These results suggest that after CPZ-induced demyelination, thyroid hormone regulates CNS remyelination process by inducing the differentiation of progenitor cells of the SVZ and accelerating OLGc maturation in the CC.