Quercetin influences in vitro maturation, apoptosis and metabolically active mitochondria of goat oocytes.

The present study aimed to investigate the effect of quercetin as an alternative antioxidant tocysteamine onin vitromaturation. Oocytes were collected from goat ovaries, destined forin vitromaturation and distributed into three groups: CIS group, oocytes were immersed inMIV base medium; in Groups Q4 and Q8, oocytes were immersed in the medium of the CISgroup, adding 4&#956;Mor8&#956;M of quercetin, respectively, and cultured for 24 h at 38.5°C with5% CO2. The CIS and Q4 groups presented the same percentage of expanded cumulus cells,but the per cent in the Q8 group was significantly lower than that of the other groups(P<0.05). The oocyte retraction rate in the Q8 group was higher (P<0.05) than in the CISand Q4 groups. Treatment with 8&#956;M of quercetin presented a lower proportion of expandedoocytes than the CIS group and 4&#956;M of quercetin (P<0.05). The percentage of MII oocyteswas higher in the Q4 group than in the CIS group (P<0.05), but the percentages in the CISand Q8 groups were similar. The rate of apoptosis was higher in the CIS group than in theother groups (P<0.05). In addition, oocytes matured with 4&#956;M quercetin showed highermitochondrial activity than matured oocytes in the CIS and Q8 groups (P