Population estimate and morphometry of ovarian preantral follicles from three recently recognized squirrel monkey species: a comparative study

Development of sheep secondary follicles and preservation of aromatase and metalloproteinases 2 and 9 after vitrification and in vitro culture

The cryopreservation of secondary follicles (SF) is a promising alternative to preserve the reproductive potential both in humans and animals in situations in which the transplantation of ovarian tissue is not possible. The objective of the present study was cryopreserved SF isolated sheep. Beyond follicular morphology, viability and development, we investigated proteins related to steroidogenic function and basement membrane remodeling [metalloproteinases 2 (MMP-2) and 9 (MMP-9)] in fresh SF (FSF) and vitrified SF (VSF) followed by in vitro culture for 6 (D6) or 12 days (D12). The percentage of intact follicles, follicular and oocyte diameter of the VSF were lower than FSF on both days of culture (P < 0.05). The VSF viability was statistically reduced from D6 (95.5%) to D12 (77.3%) but did not differ from the FSF on both days (D6:96.2% to D12:86.5%). Antrum formation in the VSF (D6: 59.13%; D12: 79.56%) was significantly lower than the FSF (D6: 79.61%; D12: 92.23%). However, an increase in this percentage was observed from D6 to D12 in both groups. Aromatase showed stronger labeling on FSF D6 and VSF D12 compared to other treatments (P < 0.05). MMP-2 showed a similar pattern of labeling in FSF D6 and VSF D12, similarly to that observed in FSF D12 and VSF D6. MMP-9 was similar in FSF and VSF cultivated for 6 and 12 days. In conclusion, VSF are able to grow and develop during 12 days of in vitro culture and showed evidence of preservation of steroidogenic function and remodeling of the basement membrane.

Morphology and morphometry of preantral follicles, and immunolocalization of angiogenic factors in ovarian tissue from the neotropical primateSapajus apella

Ovarian biopsies from five health adult monkeys were collected by exploratory laparotomy. Preantral follicles (primordial, primary, and secondary) were classified as normal or degenerated and submitted to morphometric analysis in which granulosa cell counts and the areas of follicles, oocytes, and oocyte nuclei were measured. Ovarian fragments were also immunolabelled for the quantitative analysis of VEGFA and CD31 protein expression in the ovarian tissue and in the preantral follicles. In total, 213 preantral follicles was examined for morphometry and morphological classification. From this total, 20 (9.4%) were follicles enclosing two or more oocytes, i.e. multi-oocyte follicles (MOFs). From the 193 follicles enclosing only one oocyte, 46.3% were classified as primordial, 24,1% as transition, 23.3% as primary, and 6.3% as secondary follicles. The mean number of granulosa cells surrounding primordial, transition, primary, and secondary follicles was 9.2, 12.1, 18.7, and 45.3, respectively. Increase in oocyte diameter was observed from primary to secondary follicles, while the oocyte nucleus increased only when follicles reached the secondary stage. The expression of CD31 was strong in vessels, corpus luteum, and in normal oocytes and granulosa cells from preantral follicles at all developmental stages. Likewise, VEGFA expression was observed in vessels and preantral follicles (granulosa cells, the oocyte and the oocyte nucleus). We characterized the morphology, and morphometry and expression of angiogenic factors in normal and atretic preantral follicles fromSapajus apella. This description can support the analysis of follicular quality and survival after procedures such as transplantation and cryopreservation.