Growth differentiation factor-9 improves development, mitochondrial activity and meiotic resumption of sheep oocytes after in vitro culture of secondary follicles.

Abstract

This study analysed the effect of growth differentiation factor-9 (GDF-9) on the in vitro culture of isolated ovine secondary follicles. The follicles were cultured in α-MEM supplemented with BSA, insulin, glutamine, hypoxanthine, transferrin, selenium, ascorbic acid and FSH (α-MEM+ -control medium) or α-MEM+ supplemented with 1, 10, 50 or 100ng/ml GDF-9. Next, the oocytes were destined to in vitro maturation (IVM). After 12days of culture, there were no differences regarding the percentage of normal follicles, antrum formation and follicle diameter between the treatments (p>0.05). The rates of fully grown oocytes (≥110µm) were higher (p<0.05) in 100ng/ml GDF-9 than other treatments, except for 10ng/ml of GDF-9 (p>0.05). Treatment containing 100ng/ml GDF-9 showed higher (p<0.05) mitochondrial activity than the control group. Moreover, 100ng/ml GDF-9 showed more oocytes in MI than α-MEM+ , 1 or 50ng/ml GDF-9 (p<0.05). In conclusion, 100ng/ml GDF-9 increased the growth, mitochondrial function and meiotic resumption of oocytes from in vitro grown sheep secondary follicles.