A morphological study of incubated slices of rat cerebellum in relation to postnatal age.

The morphology of incubated slices of cerebellum from rats of various ages between birth and 70-90 days was studied using light and electron microscopy. The slices were prepared using a mechanical chopper and were incubated in Krebs solution for 1 1/2-2 h. Up to 8 days of age, cellular and subcellular damage in the slices was only rarely encountered. At 14 days, the number of pyknotic cells had increased, particularly at the cut edges of the slices, but otherwise the morphology resembled that of the cerebellum fixed in situ. By 21 days, pyknosis and swelling was more extensive, the most vulnerable neurones appearing to be the Purkinje cells and the inhibitory interneurones in the molecular layer, the internal granule cell layer being relatively spared. In slices from the adult, damage had further increased to include more than 90% of the granule cells. This non-uniform preservation of the cells in the slices with respect to age is likely to have a considerable influence on results from developmental studies carried out using mechanically-chopped brain slices. When prepared by hand, using a thin blade and glass guide, slices from the adult cerebellum showed good morphological preservation.