Effect of antioxidant on in-vitro maturation of vitrified bovine oocytes

Abstract

The present study was undertaken to investigate the effect of -tocopherol on in-vitro maturation of vitrified bovine oocytes. The cumulus-oocyte-complexes (COCs) recovered from follicles (3–5 mm diameter) by aspiration and slicing techniques were equally divided into 5 (five) groups consisting 66 COCs in each. The vitrified bovine oocytes were sub-grouped into control and treatment group. The vitrified- and non-vitrified- control group of oocytes were in-vitro matured in TCM-199 media without supplementation of vitamin E. In three vitrified treatment groups, the oocytes were in-vitro cultured in TCM-199 media supplemented with vitamin E (-tocopherol) @ 50 μM, 100 μM and 200 μM, respectively. The mean percentage of cumulus cell expansion and polar body formation in non-vitrified control and vitrified control groups were 85.18±2.57 and 65.38±1.83, and 51.67±1.94 and 30.26±0.16, respectively. The rate of cumulus cell expansion and polar body formation in the oocytes of three vitrified treatment groups media supplemented with vitamin E @ 50 μM, 100 μM and 200 μM were 56.39±3.49 and 34.62±1.83, 69.95±3.20 and 56.23±1.61, and 54.44±4.73 and 31.62±4.50% respectively. Mean percentage of both cumulus cell expansion and polar body formation in the non-vitrified control group were significantly higher than that in the vitrified control group. In the treatment group supplemented with vitamin E @ 100 μM, both cumulus cells expansion and polar body formation were significantly higher than that in media supplemented with 50 μM and 200 μM vitamin E as well as in vitrified control group.