Miyoshi Kazuchika, Mizobe Yamato
Laboratory of Animal Reproduction, Faculty of Agriculture, Kagoshima University, Kagoshima 890-0065, Japan.
J Reprod Dev. 2014;60(5):349-54. doi: 10.1262/jrd.2013-135. Epub 2014 Jul 3.
The osmolarities of media that are most effective for in vitro culture of mammalian oocytes and embryos are lower than that of oviductal fluid. Oocytes and embryos can survive the high physiological osmolarity in vivo perhaps owing to the presence of amino acids such as glycine, which serve as organic osmolytes in the female reproductive tract. In the present study, the effects of glycine on the parthenogenetic development of pig oocytes were examined in hypotonic or isotonic media. The results showed that culturing oocytes in isotonic media improved the cleavage rates (P<0.01) at 2 days in culture but inhibited any further development beyond cleavage when compared with the hypotonic media. However, addition of 4 mM glycine to the isotonic media resulted in improved blastocyst formation rates compared with that observed in the hypotonic media (P<0.01), and there was no inhibition of development beyond the cleavage stages in oocytes. The beneficial effects of glycine were observed only when oocytes were cultured in isotonic media and glycine was added at day 2 or 3 in culture. The results from the present study indicate that an isotonic medium with glycine is useful for in vitro culture of pig oocytes and that glycine may protect pig oocytes against the detrimental effects of increased osmolarity.
对哺乳动物卵母细胞和胚胎进行体外培养最有效的培养基渗透压低于输卵管液。卵母细胞和胚胎在体内能够耐受高生理渗透压，这可能归因于诸如甘氨酸等氨基酸的存在，它们在雌性生殖道中作为有机渗透溶质。在本研究中，在低渗或等渗培养基中检测了甘氨酸对猪卵母细胞孤雌发育的影响。结果表明，与低渗培养基相比，在等渗培养基中培养卵母细胞在培养2天时提高了卵裂率（P<0.01），但抑制了卵裂后的进一步发育。然而，与低渗培养基相比，在等渗培养基中添加4 mM甘氨酸提高了囊胚形成率（P<0.01），并且对卵母细胞卵裂阶段后的发育没有抑制作用。仅当卵母细胞在等渗培养基中培养且在培养第2天或第3天添加甘氨酸时才观察到甘氨酸的有益作用。本研究结果表明，含甘氨酸的等渗培养基对猪卵母细胞的体外培养有用，并且甘氨酸可能保护猪卵母细胞免受渗透压升高的有害影响。
