Postnatal changes of the number and lobular distribution of acid phosphatase positive and lipid granule-containing cells in the cerebellum of hyperbilirubinemic gunn rats

Abstract

Listen

Translate article

Developing homozygous ( jj) and heterozygous ( j+) Gunn rat cerebella were examined histologically from postnatal days 5 to 60. Sagittal sections of the cerebellar vermis of jj rats revealed that the anterior and medial lobes were significantly smaller in area than in j+ rats on and after postnatal day 10. However, the nodulus did not display significant differences in jj rats. Two classes of acid phosphatase (ACPase)-positive cells (L cells and S cells) 14, and lipid granule-containing S cells were recognized exclusively in the jj rat cerebellum during the postnatal period studied. S cells, which are probably microglia, had an oval dark nucleus and contained many lysosomes, some of which contained lipid droplets. They appeared in all the lobules except the nodulus on day 5 and reached maximum in incidence by day 15. They were distributed all over the cerebellar layers including the white matter. Lipid granule-containing S cells appeared on postnatal day 10 and were most abundant in severely affected lobules, such as the declive and tuber, on day 30. Purkinje cells of jj rats showed vacuolation in their cytoplasm on and after postnatal day 5. After 20 days of life, the number of Purkinje cells in anterior- and medius-lobus were markedly decreased. Some severely damaged Purkinje cells became L cells with an extremely high ACPase activity. They appeared initially on postnatal day 15 and increased in number until day 30. No L cells were observed in the nodulus. These show that the severely damaged Purkinje cells and ACPase-positive and lipid granule-containing microglia cells are most abundant in the late- and intermediate-maturing regions of the vermis. Since they are either rare or absent in any earlier-maturing region, the nodulus, these data suggest toxic effects of bilirubin in the cerebellum are closely related to the ontogenic development of the individual cerebellar lobules.