High accumulation of lipofuscin is observed in preantral follicles of adult goat ovaries: Is it a senescence sign?

Abstract

The aim of this study was to assess the ovarian follicles and cortex morphologically, as well as the presence of signs of senescence in the ovary of goat females of different ages: young female of two months (YF2m); six months (YF6m); adult female of two years (AF2y) and four years old or older (AF4+y). The follicles included in the ovarian cortex were evaluated for morphological normality, developmental category, and follicular density, as well as stromal cell density. Signs of senescence were evaluated by the presence of lipofuscin, β-galactosidase activity, and immunostaining for γH2AX. Animals in the YF2m group showed a higher (P < 0.05) percentage of morphologically normal follicles, while animals in the AF4+y group showed a lower percentage of primordial follicles and a higher (P < 0.05) percentage of developing follicles. The follicular and stromal cell density of the YF2m group was higher (P < 0.05) than in the AF2y and AF4+y groups. Regarding senescent markers, the presence of lipofuscin in the ovary of adult animals (AF2y and AF4+y) was higher (P < 0.05) than in young animals (YF2m and YF6m). On the other hand, β-galactosidase activity did not differ between groups, and immunolabeling for γH2AX was not observed in the ovaries of the experimental animals. In conclusion, the findings of the present study indicate that in goats, the reduction in the number of morphologically normal preantral follicles is already observed at six months of age and may not be related to cellular senescence.