Quantitative analysis of the Purkinje cell and the granule cell populations in the cerebellum of nude mice.

In the nude mutant, a well-known model of athymia in mouse, abnormalities have been reported in the cerebellum, including a 45% reduction in cerebellar size and neuronal loss (Henderson et al., 1981). The present work was aimed at reappraising the claimed anomalies by using quantitative cytological techniques. We counted the Purkinje and the granule cells, on serial sagittal sections stained with thionin, in the cerebella of nude mice (nu/nu) compared with their Balb/c controls (+/+). The latero-lateral extent of the cerebellar cortex was statistically different (mean +/- standard deviation) between the nude (7.05 +/- 0.45 mm, n = 3) and the control mice (8.05 +/- 0.35 mm, n = 3) (Student's t-test, p < 0.05). The number of Purkinje cells was not statistically different (p = 0.98) between the nude mice (159,880 +/- 5,225, n = 3) and the control ones (160,060 +/- 12,300, n = 3). The number of granule cells (x 10(6)) did not differ significantly (p = 0.40) in nude mice (m = 12.1 +/- 1.8, n = 3) from the controls (m = 13.2 +/- 0.8, n = 3). Immunohistochemistry with a specific marker of Purkinje cells, calbindin protein, did not reveal any qualitative difference between the nude and the control Purkinje cells. The only slight but significant difference concerned the mean cross-sectional area of the Purkinje cell somas: 188.2 microns 2 (n = 149) in the control animals and 176.3 microns 2 (n = 150) in the nude mice, (p < 0.01). In conclusion, our data indicate only a mild effect, if any, of the nude mutation upon the cerebellar neuronal population.