B. B. Gouveia

Análise morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) da pré-puberdade até a pós-puberdade

This study describes the morphological and functional analysis of spermatogenesis in guinea pigs (Cavia porcellus) with five (W5), six (W6), nine (W9) and eleven (W11) weeks of age (n=5/group). The aspects analyzed include counts of cell populations present in stage 1 of seminiferous epithelium cycle (SEC), efficiency of spermatogonial mitosis (EMi), meiotic production (EMe), overall yield of spermatogenesis (EOS), Sertoli cell index (SCI) and carrying capacity of Sertoli cells (CCSC). The results showed that the average number of spermatogonia type A, primary spermatocytes in pre-leptoteno/leptoteno, primary spermatocytes in pachytene, total spermatogenic cells and Sertoli cells showed numerical variations according to age; however they were statistically not detected, while round spermatids increased significantly at puberty and then stabilized. The spermatogenic production of 5 to 11-week-old guinea pigs did not reach the stabilization point, and the RMi, RME, EOS, SCI and CCSC showed significant number variation as a function of age. The results demonstrate that Cavia porcellus in post-pubertal stage 2 are an advantageous experimental model to address studies on the processes of homologous recognition, alignment, and synapsis during meiotic prophase; intrinsic yield of spermatogenesis in guinea pigs is similar to Wistar rats, paca and agouti (Dasyprocta sp.) and lower than in cavies, whereas the functional efficiency of Sertoli cells is higher than in agouti and Wistar rats, and lower than in pacas, spiny rat and collared peccaries. We conclude that in guinea pigs the spermatogenesis is fully established at 6 weeks of age, indicating the pubertal stage of sexual development, and until week 11 they do not reach the maximum daily sperm production and therefore sexual maturity.

Influence of the ovarian fragmentation before storage at 4°C on the apoptosis rates and in vitro development of ovine preantral follicles

The aim of this study was to evaluate the effect of ovarian tissue fragmentation before preservation at 4°C in MEM on the morphology, apoptosis, and growth of ovine preantral follicles. After collection, the ovaries were divided into two halves, being one divided into two fragments (1/4 of the ovary). One fragment was subdivided into two fragments (1/8), being one fixed for histology (fresh control). The remaining whole ovary, 1/2, 1/4 and 1/8 of the ovary were preserved in MEM at 4°C for 6, 12 or 24 h. The tissue was further destined to histology. In vitro culture and TUNEL technique were performed in treatments that showed the best results of follicular survival after preservation. Storage of 1/8 of the ovary increased the normal follicles compared with half or whole ovary. After preservation in 1/8 of the ovary and culture for 7 days, the percentage of apoptotic cells was similar to the fresh control and non-cultured fragments. The percentage of growing follicles increased after preservation of 1/8 of the ovary compared with 1/4. In conclusion, ovine preantral follicles can be preserved in fragments of 1/8 of the ovary in MEM at 4°C for 24 h, without affecting apoptosis and their ability to grow in vitro .

Extract of Amburana cearensis maintains the survival of ovine preantral follicles during long-term ovarian tissue transport and promotes primordial follicle activation after in vitro culture

This study evaluated the effect of Amburana cearensis extract as a preservation or culture medium for ovine ovarian tissue. Ovarian fragments were fixed in 4% buffered formaldehyde for 18 h (fresh control), stored in Minimal Essential Medium (MEM) or in A. cearensis extract (0.1; 0.2 or 0.4 mg/mL) at a temperature of 4oC for 6, 12 or 24 h (preservation - experiment 1) or cultured for 7 days in ?-MEM+ or in A. cearensis extract without (0.1; 0.2 or 0.4 mg/mL) or with supplements (0.1+ ; 0.2+ or 0.4+ mg/ mL; experiment 2). The percentages of morphologically normal follicles and follicular activation were submitted to analysis of variance (ANOVA) and Tukey´s test. The values of TUNEL-positive cells were submitted to Chi-square test (P 0.05). Moreover, after in vitro culture, A. cearensis at a concentration of 0.1 mg/mL maintained the percentage of TUNEL positive cells (30.0%) in a way that is similar to that observed in the fresh control (22%) (P > 0.05). In conclusion, ovine preantral follicles can be preserved at 4°C in MEM for 6 h. For longer periods of preservation (24 h), MEM and 0.2 mg/mL A. cearensis are recommended. Moreover, after in vitro culture, A. cearensis extract (0.1 mg/mL) showed higher activation and lower DNA fragmentation in ovine preantral follicles.