Effect of fixative type and fixation time on the morphology of bovine preantral ovarian follicles

Abstract

There are no efficient fixatives for histological analyses of ovarian tissue that permit an appropriate morphological analysis of ovary and their cells. The correct processing of the tissue is essential to avoid misinterpretation between follicular degeneration due to the physiological process of follicular atresia with signs of degeneration signals due to poor tissue fixation. This study aimed to identify the best fixative and better fixation period for morphological analysis of the functional unit of the ovary: follicle. Ovaries (n = 5) from five adult cows were collected from local abattoirs. Each ovary was divided into 12 fragments and submitted to six different fixatives in two different times (12 and 24h). It was analyzed 150 follicles per treatment. The best results were obtained with Carnoy’ and Bouin’s fixatives which had higher (P < 0.05) proportion of viable follicles after fixation for 12 or 24h (88 and 83% for Carnoy’s fixative vs. 79 e 73% for Bouin). It was concluded that Carnoy and Bouin fixatives are the best options to preserve for up to 24 h the morphology of preantral follicles in bovine ovaries.