Effects of thyroid hormone deficiency on glial constituents in developing cerebellum of the rat

Rat litters were treated daily from birth with the antithyroid drug propylthiouracil for 2 or 4 weeks, respectively. Transverse cryostat sections of cerebellar cortex with underlying white matter were incubated with antiserum against glial fibrillary acidic protein. Semiquantitative microscopic evaluations showed a marked decrease in width of the molecular layer in thyroid deficient animals 2 weeks postnatally, as compared to controls. Also, the well delineated GFA-positive glial cell layer extending along the border between white matter and the internal granular layer was absent in thyroid deficient animals. The density of GFA immunoreactivity was increased in white matter in the experimental group. No effects of thyroid deficiency on GFA immunoreactivity could be found after 4 weeks of treatment, indicating a transient disturbance of glial development in the thyroid deficient cerebellum.