de Matos D G, Furnus C C, Moses D F
Centro de Investigaciones Reproductivas Pérez Companc, Buenos Aires, Argentina.
Biol Reprod. 1997 Dec;57(6):1420-5. doi: 10.1095/biolreprod57.6.1420.
Glutathione (GSH) synthesis during in vitro maturation (IVM) has been shown to play an important role in embryo development. The present study was carried out to evaluate the role of cumulus cells in GSH synthesis during IVM of bovine oocytes in the presence of cystine, cysteine, the cysteine analogue N-acetylcysteine, and cysteamine. For this purpose, cumulus-oocyte complexes (COCs), denuded oocytes (DOs), and DOs in coculture with a cumulus cell monolayer were used. An increase in GSH level stimulated by cystine was observed only in the presence of cumulus cells, either with COCs or in DOs matured on a coculture monolayer. Addition of cysteine and cysteamine to IVM medium increased GSH levels in COCs and DOs. N-Acetylcysteine increased GSH levels only in DOs. Moreover, cumulus cells contributed to the stimulatory effect exerted by cysteine and cysteamine on GSH synthesis in COCs. These results indicate that cumulus cells during IVM play an important role in oocyte GSH synthesis, allowing the oocytes to use cystine and contributing to the stimulatory effect exerted by cysteine and cysteamine. In addition, these results demonstrate that IVM medium supplemented with cysteine or cysteamine increased GSH content in oocytes without cumulus mass (DO) and in the absence of a cumulus cell monolayer. This may be useful to increase the efficacy of IVM of those oocytes having few cumulus cell layers, in a system without coculture.
体外成熟（IVM）过程中谷胱甘肽（GSH）的合成已被证明在胚胎发育中起重要作用。本研究旨在评估卵丘细胞在牛卵母细胞IVM过程中，在胱氨酸、半胱氨酸、半胱氨酸类似物N - 乙酰半胱氨酸和半胱胺存在的情况下，对GSH合成的作用。为此，使用了卵丘 - 卵母细胞复合体（COCs）、裸卵（DOs）以及与卵丘细胞单层共培养的DOs。仅在存在卵丘细胞时，无论是与COCs一起还是在共培养单层上成熟的DOs中，观察到胱氨酸刺激的GSH水平增加。向IVM培养基中添加半胱氨酸和半胱胺可提高COCs和DOs中的GSH水平。N - 乙酰半胱氨酸仅在DOs中提高了GSH水平。此外，卵丘细胞有助于半胱氨酸和半胱胺对COCs中GSH合成的刺激作用。这些结果表明，IVM过程中的卵丘细胞在卵母细胞GSH合成中起重要作用，使卵母细胞能够利用胱氨酸，并有助于半胱氨酸和半胱胺发挥刺激作用。此外，这些结果表明，在没有卵丘团块（DO）且没有卵丘细胞单层的情况下，添加半胱氨酸或半胱胺的IVM培养基可增加卵母细胞中的GSH含量。这对于在没有共培养的系统中提高那些卵丘细胞层数少的卵母细胞的IVM效率可能是有用的。
