Cerebellar Purkinje cell loss during life span of the heterozygous staggerer mouse (Rora(+)/Rora(sg)) is gender-related.
The staggerer mutation causes dysgenesis of the cerebellar cortex in the homozygous mutant (Rora(sg)/Rora(sg)). The mutation acts intrinsically within the Purkinje cells (PCs), leading to cytological abnormalities and a severe deficit in the number of these cells. In contrast, in the heterozygous staggerer (Rora(+)/Rora(sg)), the cytoarchitecture of the cerebellar cortex appears to be normal, but quantitative studies have revealed a significant loss of cerebellar neurons with advancing age. In the heterozygous reeler (+/rl), another mutant presenting a PC loss with age, we have found that only males were affected (Hadj-Sahraoui et al., 1996). In the present study, we have investigated whether a similar gender effect exists in the heterozygous staggerer during life span. PCs were counted on cerebellar sagittal sections in male and female Rora(+)/Rora(sg) and in their Rora(+)/Rora(+) littermates at 1, 3, 9, 13, 18, and 24 months of age. In the Rora(+)/Rora(+), the number of PCs remained stable until 18 months, but there was a 25% significant loss in 24- month-old mice of both genders. During life span, Rora(+)/Rora(+) males had slightly more PC than females. In the Rora(+)/Rora(sg) of both genders, the deficit in PC number was similar at 13 months but it appeared earlier in males, beginning between 1 and 3 months, and was aggravated regularly up to 13 months. By contrast, the decline was delayed and more abrupt in Rora(+)/Rora(sg) females, from a value still normal at 9 months to its maximal extent at 13 months. In view of these results, the heterozygous (Rora(+)/Rora(sg)) mouse offers an interesting model to test the interaction between sex, age, and genetic background on the development and maintenance of cerebellar neuronal populations.
Doulazmi
M
M
Laboratoire de Neurobiologie du Développement, Institut des Neurosciences (UMR 7624 CNRS), Université P. & M. Curie, 75005 Paris, France.
Frédéric
F
F
Lemaigre-Dubreuil
Y
Y
Hadj-Sahraoui
N
N
Delhaye-Bouchaud
N
N
Mariani
J
J
D000375:Aging; D000818:Animals; D002525:Cerebellar Cortex / Q000166:cytology / Q000254:growth & development; D002531:Cerebellum / Q000166:cytology / Q000254:growth & development*; D005260:Female; D005838:Genotype; D006579:Heterozygote; D008297:Male; D051379:Mice; D008818:Mice, Neurologic Mutants / Q000235:genetics / Q000254:growth & development*; D011689:Purkinje Cells / Q000166:cytology* / Q000502:physiology; D012727:Sex Characteristics; D013045:Species Specificity