Cerebellar Development in the Rat After Early Postnatal Damage by Methylazoxy‐methanol: Dna, Rna and Protein During Recovery

Abstract —Total cerebellar DNA, RNA, protein and wet weight were determined for normal cerebellum and for cerebellum damaged early in postnatal development by the neurotoxic action of the drug methylazoxymethanol (MAM) acetate. Injections of a 10 mg/kg dose of the drug were given on postnatal days 1, 2, 3 and 4 as a means of inducing a transient insult to the proliferating stem cell population of the external granular layer. Cerebellar DNA and other quantitative measures were reduced to 50 per cent of normal at day 7. Growth in the MAM‐treated cerebellum was relatively more rapid than in normals so that the eventual deficit in the adult was 80 per cent of normal. We concluded that early postnatal transient injury of the developing cerebellum is followed by a regenerative phase of repair but that quantitatively significant mitosis in the injured cerebellum ceases normally at about post‐natal day 17. The conditions evaluated in this investigation may serve as a model for other types of injury induced by drugs, irradiation, viruses or nutritional factors.