Astroglial development in microencephalic rat brain after fetal methylazoxymethanol treatment.

Treatment of pregnant rats on gestation day 15 with methylazoxymethanol (MAM) leads to a marked microencephaly in the offspring with a considerable atrophy in cerebral cortex, hippocampus and striatum. The development of the astrocytic populations in these atrophic regions was studied by means of immunohistochemistry using an antiserum against glial fibrillary acidic protein (GFA). The distribution and density of GFA-positive structures were not notably altered in the parietal cortex, hippocampal formation and striatum after prenatal MAM-treatment as compared to control. Also the individual astrocytes were morphologically similar in experimental and control animals in all regions analyzed. We suggest that an adjustment of the astrocytic development has occurred in response to the changed neuronal environment. Alternatively, MAM-treatment may affect neuronal and glial precursor cells leading to a seemingly normal astrocytic cell density.