Follicular Fluid from Infertile Women with Mild Endometriosis Impairs In Vitro Bovine Embryo Development: Potential Role of Oxidative Stress

Abstract Objective To investigate whether follicular fluid (FF) from infertile women with mild endometriosis (ME) alters in vitro bovine embryo development, and whether the antioxidants N-acetyl-cysteine (NAC) and/or L-carnitine (LC) could prevent such damages. Methods Follicular fluid was obtained from infertile women (11 with ME and 11 control). Bovine oocytes were matured in vitro divided in: No-FF, with 1% of FF from control women (CFF) or ME women (MEFF); with 1.5mM NAC (CFF + NAC, MEFF + NAC), with 0.6mg/mL LC (CFF + LC, MEFF + LC), or both antioxidants (CFF + NAC + LC, MEFF + NAC + LC). After in vitro fertilization, in vitro embryo culture was performed for 9 days. Results A total of 883 presumptive zygotes were cultured in vitro. No differences were observed in cleavage rate (p = 0.5376) and blastocyst formation rate (p = 0.4249). However, the MEFF group (12.5%) had lower hatching rate than the No-FF (42.1%, p = 0.029) and CFF (42.9%, p = 0.036) groups. Addition of antioxidants in the group with CFF did not alter hatching rate (p ≥ 0.56), and in groups with MEFF, just NAC increased the hatching rate [(MEFF: 12.5% versus MEFF + NAC: 44.4% (p = 0.02); vs MEFF + LC: 18.8% (p = 0.79); versus MEFF + NAC + LC: 30.8% (p = 0.22)]. Conclusion Therefore, FF from infertile women with ME added to medium of in vitro maturation of bovine oocytes impairs hatching rate, and NAC prevented these damages, suggesting involvement of oxidative stress in worst of oocyte and embryo quality of women with ME.

摘要
目的：探讨轻度子宫内膜异位症（mild endometriosis, ME）不孕女性的卵泡液（follicular fluid, FF）是否会影响牛体外胚胎发育，以及抗氧化剂N-乙酰半胱氨酸（N-acetyl-cysteine, NAC）和/或左旋肉碱（L-carnitine, LC）能否逆转此类损伤。
方法：本研究采集11例轻度子宫内膜异位症不孕女性与11例对照女性的卵泡液；将牛卵母细胞进行体外成熟培养，分为以下组别：无FF组（No-FF）、添加1%对照组女性卵泡液组（CFF）、添加1%轻度子宫内膜异位症患者卵泡液组（MEFF）；在此基础上分别添加1.5mM NAC（对应CFF+NAC、MEFF+NAC组）、0.6mg/mL LC（对应CFF+LC、MEFF+LC组），或同时添加两种抗氧化剂（对应CFF+NAC+LC、MEFF+NAC+LC组）。体外受精后，将胚胎进行为期9天的体外培养。
结果：本研究共体外培养883枚疑似受精卵，各组卵裂率（p=0.5376）与囊胚形成率（p=0.4249）均无显著差异。但MEFF组胚胎孵化率（12.5%）显著低于无FF组（42.1%，p=0.029）与CFF组（42.9%，p=0.036）。在CFF组中添加抗氧化剂未改变胚胎孵化率（p≥0.56）；而在MEFF组中，仅NAC可提升胚胎孵化率：MEFF组为12.5%，MEFF+NAC组为44.4%（p=0.02），MEFF+LC组为18.8%（p=0.79），MEFF+NAC+LC组为30.8%（p=0.22）。
结论：综上，将轻度子宫内膜异位症不孕女性的卵泡液添加至牛卵母细胞体外成熟培养液中，会降低胚胎孵化率；NAC可逆转此类损伤，提示氧化应激参与了轻度子宫内膜异位症患者卵母细胞与胚胎质量的恶化过程。