Alpha-tocopherol and Ascorbic Acid Combinations Influence the Maturation of Sheep Oocytes
Keywords:
α-tocopherol, ascorbic acid, maturation, oocyte, sheepAbstract
The goal of this research was to establish whether supplementation with combinations of α-tocopherol and ascorbic acid could improve the maturation and expansion of sheep cumulus-oocyte complexes. Sheep oocytes were cultured for 24 hours at 37°C in 5.4% CO2 atmosphere in M199 containing 20 µM α-tocopherol+750 µM ascorbic acid or 5 µM α-tocopherol+250 µM ascorbic acid. Afterwards, cumulus oophorus expansion was assessed and oocytes were denuded. The presence of the first polar body was assessed by fluorescent staining with Hoechst 33258. Differences between treatments were analyzed by the analysis of variance and interpreted using the LSD test. Supplementation with the combination of 20 µM α-tocopherol+750 µM ascorbic acid resulted in significantly greater (p<0.05) percentages of COCs that were scored as 3. However, the number of COCs scored at 4 decreased. The same dynamic could be seen when oocytes were checked for the presence of the first polar body. Percentages decreased with the increase in antioxidant concentration. This indicates that although antioxidants, in these particular concentrations have been proven to have a positive influence on swine oocyte maturation the same cannot be said for ovine female gametes.
References
Watson, A.J., The multifaceted complex of factors involved in oocyte growth constitutes the backbone on which oocyte developmental competence is built up, Journal of Animal Science, 2007, 85(E. Suppl.), E1-E3
Zuccotti, M., Merico V., Cecconi S., Redi C.A., Garagna S., What does it take to make a developmentally competent mammalian egg?, Human Reproduction Update, 2011, 17(4), 525-540
McEvoy, T., Coull G., Broadbent P., Hutchinson J. and Speake B., Fatty acid composition of lipids in immature cattle pig and sheep oocytes with intact zona pellucid, Journal of Reproduction and Fertility, 2000, 118, 163–170
Socaciu, C., Antioxidant phytochemicals: chemical characterization, functions and actions, UASMV-CN Bulletin, Agriculture ISSN 1454-2382, 2002, 57, 22-29.
Tao, Y., Zhou B., Xia G., Wang F., Wu Z. and Fu M., Exposure to L-ascorbic acid or α-tocopherol facilitates the development of porcine denuded oocytes from metaphase I to metaphase II and prevents cumulus cells from fragmentation, Reproduction of Domestic Animals, 2004, 39, 52–57
Olson, S.E., Seidel G.E., Culture of in vitro-produced bovine embryos with vitamin E improves development in vitro and after transfer to recipients, Biology of Reproduction, 2000, 62, 248–252
Warren, S., Patel S., Kapron C.M., The effect of vitamin E exposure on cadmium toxicity in mouse embryo cells in vitro, Toxicology, 2000, 142, 119–126
Chow, CK., Vitamin E and oxidative stress, Free Radical Biology & Medicine, 1991, 11, 215-232
Wang, X., Falcone T., Attaran M., Goldberg J.M., Agarwal A., Sharma R.K., Vitamin C and vitamin E supplementation reduce oxidative stress–induced embryo toxicity and improve the blastocyst development rate, Fertility and Sterility, 2002, 78, 1272-1277
Saikhun, K, Faisaikarm T., Ming Z., Lu K.H., Kitiyanant Y., α-Tocopherol and L-ascorbic acid increase the in vitro development of IVM/IVF swamp buffalo (Bubalus bubalis) embryos, Animal, 2008, 2, 1486-1490
Jeong, Y.W., Park S.W., Hossein M.S., Kim S., Kim J.H., Lee S.H., Kang S.K., Lee B.C., Hwang W.S., Antiapoptotic and embryotrophic effects of α-tocopherol and L-ascorbic acid on porcine embryos derived from in vitro fertilization and somatic cell nuclear transfer, Theriogenology, 2006, 66, 2104-2112
Miclea, I., Zăhan M., Miclea V., Hettig A., Roman I., Ghiuru F., Influence of Alpha-tocopherol on swine embryo development, Bulletin UASVM, Animal Science an Biotechnologies, 2010, 67(1-2), 403-408
Downs, S.M., Specificity of epidermal growth factor action on maturation of the murine oocyte and cumulus oophorus in vitro, Biology of Reproduction, 1989, 41, 371–379
Peng, X.R., Liu T., Zhang Y., Addition of alpha-tocopherol to culture medium improves the quality and cryosurvival of nuclear-transferred ovine embryos, Journal of Reproduction and Developemnt, 2008, 54(6), 403-7
Natarajan, R., Bhawani S.M., Munuswamy D., Effect of α-tocopherol supplementation on in vitro maturation of sheep oocytes and in vitro development of preimplantation sheep embryos to the blastocyst stage, Journal of Assisted Reproduction and Genetics, 2010a, 27, 483–490
Natarajan, R., Bhawani S.M., Munuswamy D., Effect of L-ascorbic acid supplementation at different gaseous environments on in vitro development of preimplantation sheep embryos to the blastocyst stage, Animal Reproduction Science, 2010, 7(1), 21-28
Miclea, I., Păcală N., Zăhan M., Hettig A., Roman I., Miclea V., Influence of alpha-tocopherol and ascorbic acid on swine oocyte viability and maturation, 2011, Bulletin UASVM Animal Science and Biotechnologies, 68(1-2), 338-345.
