Resveratrol has dose-dependent effects on DNA fragmentation and mitochondrial activity of ovine secondary follicles cultured in vitro.

The worldwide consumption of red wine, nuts and grapes has resulted in increased human exposure to resveratrol, which could affect reproductive function. However, the effect of resveratrol on in vitro culture of early-stage ovarian follicles has never been investigated. The aims of the present study were to evaluate the effect of resveratrol on sheep secondary follicle morphology, growth, DNA fragmentation, intracellular levels of glutathione (GSH) and active mitochondria. Secondary follicles were isolated from the ovaries and cultured for 18 days in supplemented α-MEM+ (control medium) or in control medium containing resveratrol (2, 10 or 30 µM). The parameters analyzed were morphology, antrum formation, follicle diameter, DNA fragmentation, GSH levels and mitochondrial activity. After 18 days, all resveratrol groups significantly decreased the percentages of morphologically normal follicles compared with the control group (α-MEM+). Antrum formation was higher in both α-MEM+ and 2 µM resveratrol groups than in the 10 µM resveratrol group. In addition, 30 µM resveratrol increased the percentage of oocytes with DNA damage compared with the control. Oocytes from follicles treated with 10 or 30 µM resveratrol significantly decreased intracellular GSH levels compared with the 2 µM resveratrol group. Moreover, follicles in α-MEM+ (control) showed more active mitochondria than those in 10 or 30 µM resveratrol. In conclusion, ovine isolated secondary follicles are able to grow to the antral stage after in vitro culture in medium containing 2 µM resveratrol, maintaining the same rates of DNA damage, GSH levels and mitochondrial function as the control medium. However, the addition of 30 µM resveratrol increased DNA fragmentation and oxidative stress through decreasing mitochondrial activity.