Isorhamnetin improves in vitro maturation of oxidative stress-exposed porcine oocytes and subsequent embryo development.

This study investigated the effect of the flavonoid-based compound isorhamnetin (ISO) on maturation and developmental competence in oxidative stress-exposed porcine oocytes in vitro . Treatment with 2 μM ISO (2 ISO) increases the developmental rate of oxidative stress-exposed porcine oocytes during in vitro maturation (IVM). The glutathione level and mRNA expression of antioxidant-related genes ( NFE2L2 and SOD2 ) were increased in the 2 ISO-treated group, whereas the reactive oxygen species level was decreased. Treatment with 2 ISO increased mRNA expression of a cumulus cell expansion-related gene ( SHAS2 ) and improved chromosomal alignment. mRNA expression of maternal genes ( CCNB1, MOS, BMP15 and GDF9 ) and mitogen activated protein kinase (MAPK) activity were increased in the 2 ISO-treated group. The total cell number per blastocyst and percentage of apoptotic cells were increased and decreased in the 2 ISO-treated group, respectively. Treatment with 2 ISO increased mRNA expression of development-related genes ( SOX2, NANOG , and POU5F1 ) and anti-apoptotic genes ( BCL2L1 and BIRC5 ) and decreased that of pro-apoptotic genes ( CASP3 and FAS ). These results demonstrate that 2 ISO improves the quality of porcine oocytes by protecting them against oxidative stress during IVM and enhances subsequent embryo development in vitro . Therefore, we propose that ISO is a useful supplement for IVM of porcine oocytes.