We investigated the hypothesis that reduced glutathione (GSH) is present in secretions of the female reproductive tract and that this extracellular GSH may protect preimplantation mouse embryos after intracellular GSH depletion. The cleavage-stage mouse embryo cannot synthesize GSH de novo and is unable to recover from glutathione depletion in vitro. Analysis of GSH and total protein of oviduct flushings, quantified by HPLC and the Bradford method, respectively, revealed 51 nmol GSH per mg total protein. Embryos were treated with 60 microM diethyl maleate (DEM) to deplete cellular GSH. When cultured with 1 mM GSH, these embryos exhibited improved development compared to those cultured in control medium (96% vs. 87% morula [p < 0.05], 78% vs. 75% blastocyst, 58% vs. 54% expanded blastocyst, 21% vs. 17% initiating hatching blastocyst). However, intracellular GSH content of embryos was not significantly increased by the culture of DEM-treated embryos in medium containing GSH for 16, 40, or 64 h of incubation, suggesting that the embryo is not capable of taking up intact GSH. Furthermore, addition of buthionine sulfoximine (which inhibits synthesis of GSH) or acivicin (which inhibits breakdown of GSH at the membrane) to culture medium blocked the improvement in development. These data suggest that GSH in reproductive tract fluid may help protect preimplantation embryos from the adverse effects of toxicant-induced and endogenous depletion of embryonic GSH.
開始_電腦翻譯的中文
我們研究了以下假設：還原型穀胱甘肽 (GSH) 存在於女性生殖道的分泌物中，而這種細胞外 GSH 可以在細胞內 GSH 耗盡後保護植入前小鼠胚胎。卵裂期小鼠胚胎無法從頭合成穀胱甘肽，且無法在體外從穀胱甘肽耗盡中恢復。分別以 HPLC 和 Bradford 法定量分析輸卵管沖洗液的 GSH 和總蛋白，結果顯示每毫克總蛋白含有 51 nmol GSH。用 60 µM 馬來酸二乙酯 (DEM) 處理胚胎以消耗細胞 GSH。當用1 mM GSH 培養時，與在對照培養基中培養的胚胎相比，這些胚胎表現出更好的發育（96% vs. 87% 桑葚胚[p < 0.05]、78% vs. 75% 囊胚、58% vs. 54% 囊胚、 21% vs. 17% 起始孵化囊胚）。然而，將 DEM 處理的胚胎在含有 GSH 的培養基中培養 16、40 或 64 小時，胚胎的細胞內 GSH 含量並未顯著增加，這表明胚胎無法吸收完整的 GSH。此外，在培養基中添加丁硫氨酸亞砜亞胺（抑制 GSH 合成）或阿西維星（抑制 GSH 在膜上的分解）會阻礙發育的改善。這些數據表明，生殖道液體中的穀胱甘肽可能有助於保護植入前胚胎免受有毒物質誘導的和胚胎穀胱甘肽內源性消耗的不利影響。
結束_電腦翻譯的中文
沒有留言:
張貼留言