Citología y análisis morfométrico de las células del epitelio vaginal durante el ciclo estral en ovejas de pelo (Ovis aries)

Abstract

Vaginal cytology can be used to characterize stages of the reproductive cycle of the female. However, it has not been validated in hair sheep, and generates inaccurate results due to subjective interpretations. Thus, the purpose of the present work is to typify morphologic and morphometric characteristics of the epithelial cells from the vagina during the estrous cycle of hair sheep. Five Saint Croix ewes were synchronized with intravaginal sponges. Day zero of the cycle was considered the day of first estrus after sponge withdrawal. From this day until next estrus, samples from the vaginal epithelium were obtained daily from each ewe. The number of basal, intermediate and superficial cells was quantified, and length, perimeter, and area from cytoplasm and nucleus were obtained. The results show that the number of superficial cells increase (P<0.05) during estrus and decrease during the rest of the cycle. In contrast, the number of basal and intermediate cells showed an inverse pattern. The largest cells (36.11±0.38 μm) and smallest nucleuses (8.46±0.12 μm) were present during estrus, regardless of the cell type, while the smallest cells (26.72±0.11 μm) and larger nucleuses (10.48±0.02 μm) were observed during diestrus. It was concluded that citology of the epithelial cells from the vagina of hair ewes is in accord with changes found in other female spices, and that cytoplasm and nucleus sizes display a cyclic pattern that might be used to objectively determine the specific estrous cycle phase of the ewes.