Effect of different concentrations of recombinant follicle stimulating hormone on the in vitro development of preantral follicles isolated from goats and sheep

Abstract

The aim of this work was to evaluate the effects of recombinant follicle stimulating hormone (rFSH) on the in vitro development of isolated caprine and ovine preantral follicles. Preantral follicles (≥ 150 micron) were isolated from fragments of goats and sheeps ovarian cortex and individually cultured for 24 days in α-MEM supplemented with 10% fetal calf serum (FCS), 1% insulin-transferrin -selenium (ITS), 1% antibiotics and 50 mg / mL ascorbic acid, in the absence (control) or presence of FSHR (100 or 1000 ng / mL) at 39 ° C with 5% CO2 in air. Follicular morphology, growth and antral cavity formation were assessed throughout the culture. The results showed that addition of rFSH to the medium had no effect on the percentages of caprine morphologically normal follicles until day 12 as compared with the control, but a decrease was observed on day 18 with the use of the hormone (p<0.05) only rFSH (1000 ng/mL). Regarding ovine follicles, percentages of normal follicles were significantly reduced from day 12 onwards in all treatments, which led to similar results. Growth rates were increased in caprine follicles by use of rFSH (100 and 1000 ng/ml) in comparison to the control (p<0,05). In ovine follicles, such effect was observed only when rFSH was used at 1000 ng/ml. With respect to antral cavity formation, no diference among treatments was observed for both species. The analysis of chromatin configuration revealed that all oocytes remained at the germinal vesicle stage. In conclusion, caprine and ovine preantral follicles are capable to survive and develop to the antral stage in vitro without FSH. However, this hormone is important for increasing follicular growth rates in both species.