Caracterización morfológica y funcional de ovocitos de cobaya en dos estadios del ciclo estral

Abstract

The morphological and functional characteristics of guinea pig oocytes were studied according to the type of COC and stage of the estrous cycle. Forty guinea pigs, synchronized with oral progesterone (Regumate®) for 15 days, were used. Ovaries were collected at periovulatory (day 2) and diestrous (day 9) post-synchronization stage, and 100% of COCs were categorized by morphology into A, B and C. Mitochondrial distribution (MD), nuclear status, oocyte diameter and zona pellucida (ZP) thickness were determined, and in 50% of these, Brilliant Cresyl Blue (BCB) staining was applied. A total of 1053 COCs were obtained (49.9% periovulatory and 50.1% diestrous). From these, 23% were A, 47.5% B and 29.5% C. It was determined that in the periovulatory stage there was a greater percentage of BCB+, while in the diestrous stage a greater percentage of BCB- was obtained. In both the periovulatory and diestrous stage, diffuse DM had a greater percentage with statistical significance. There was a greater proportion of immature oocytes followed by degenerate and the mature oocytes in both stages of the estrous cycle. Oocytes in diestrous were larger in diameter than oocytes in periovulatory (p=0.0126), while the zona pellucida was thicker in periovulatory than in diestrous (p<0.0001). In conclusion, the application of non-invasive methods in guinea pig oocytes to identify characteristics of quality, development, maturation and morphometry were effective.