The development and integrity of equine pre-antral follicles cultured in vitro with follicle-stimulating hormone (FSH) supplementation.

Abstract

This study investigated the effects of different concentrations of FSH (10, 50, 100 and 200ng/ml) in supplemented MEM+ on the development of equine pre-antral follicles that were cultured in vitro for 2 or 6days. The ovaries (n=5) from mares in seasonal anoestrus were collected from a local abattoir. Ten ovarian tissue fragments of approximately 3×3×1mm were obtained from each animal. The fragments were cultured in situ for 2days (D2) or 6days (D6) in MEM+ or MEM+ supplemented with FSH at four different concentrations, establishing the following 11 groups: control (D0); MEM+(D2); MEM+(D6); MEM+10ng/ml of FSH (D2); MEM+10ng/ml of FSH (D6); MEM+50ng/ml of FSH (D2); MEM+50ng/ml of FSH (D6); MEM+100ng/ml of FSH (D2); MEM+100ng/ml of FSH (D6); MEM+200ng/ml of FSH (D2); and MEM+200ng/ml of FSH (D6). Follicles were observed in only 9.65% (388 of 4,018) of the histological sections. Of the 861 follicles evaluated, 488 were in the primordial stage, and 373 were in various developmental stages; 59.7% were morphologically normal. Regarding the integrity of the pre-antral follicles, the groups with 100ng/ml FSH of 2-days culture as well as 50, 100 and 200ng/ml FSH of 6-days culture provided the best results. In conclusion, the in vitro culture of abattoir-derived equine ovarian fragments presented better morphological integrity when supplemented with FSH for 6days, in comparison with the MEM culture group. However, no clear effects were observed with FSH regarding the promotion of activation from a primordial to a developing follicle.