N-acetyl-L-cysteine Improves the Developmental Competence of Bovine Oocytes and Embryos Cultured In Vitro by Attenuating Oxidative Damage and Apoptosis

Abstract

Oxidative stress has been suggested to negatively affect oocyte and embryo quality and developmental competence, resulting in failure to reach full term. In this study, we investigated the effect of N-acetyl-L-cysteine (NAC), a cell-permeating antioxidant, on developmental competence and the quality of oocytes and embryos upon supplementation (0.1–10 mM) in maturation and culture medium in vitro using slaughterhouse-derived oocytes and embryos. The results show that treating oocytes with 1.0 mM NAC for 8 h during in vitro maturation attenuated the intracellular reactive oxygen species (ROS) (p < 0.05) and upregulated intracellular glutathione levels (p < 0.01) in oocytes. Interestingly, we found that NAC affects early embryonic development, not only in a dose-dependent, but also in a stage-specific, manner. Significantly (p < 0.05) decreased cleavage rates (90.25% vs. 81.46%) were observed during the early stage (days 0–2), while significantly (p < 0.05) increased developmental rates (38.20% vs. 44.46%) were observed during the later stage (from day 3) of embryonic development. In particular, NAC supplementation decreased the proportion of apoptotic blastomeres significantly (p < 0.05), resulting in enhanced hatching capability and developmental rates during the in vitro culture of embryos. Taken together, our results suggest that NAC supplementation has beneficial effects on bovine oocytes and embryos through the prevention of apoptosis and the elimination of oxygen free radicals during maturation and culture in vitro.

Effects of N Acetylcysteine on the Expression of Genes Associated with Reproductive Performance in the Goat Uterus during Early Gestation

“…The addition of trace amounts of NAC during oocyte maturation increases blastocyst rates, promotes early embryo formation, improves the success of early embryo development, and reduces embryo loss [ 12 ]. NAC improves the reproductive performance of animals [ 13 ], increases sperm counts and viability [ 14 ], and significantly regulates fertility in female rats, which results in the effective amelioration of gonadal hormone disorders and improvements in reproductive function by inhibiting the activation of NADPH oxidase [ 15 ]. In addition, NAC can prevent MXC-induced granulosa cell apoptosis and follicular atresia by reducing the oxidative stress induced by methoxychlor (MXC) and decreasing the ROS signalling pathway of apoptosis [ 16 ].…”

L‐Cysteine improves bovine oocyte developmental competence in vitro via activation of oocyte‐derived growth factors BMP‐15 and GDF‐9

“…Antioxidant supplementation can lower oxidative stress by lowering ROS levels directly or by increasing glutathione (GSH) levels in oocytes during IVM (Sovernigo & Adona, 2017). To date, various antioxidants have been used during oocyte and embryo cultures in vitro (Sun et al., 2021). Surprisingly, extracellular GSH cannot penetrate the cell membrane to enter the oocytes, and its level depends mainly on the ability of cumulus cells in trapping thiols to synthesize GSH (Li et al., 2018).…”

Role of N-acetylcysteine treatment in women with advanced age undergoing IVF/ICSI cycles: A prospective study

“…The mitochondrial function might be improved with the application of antioxidants. Oxidative stress was regarded as a causative factor for aging, which was also a prominent mediator associated with oocyte damage and causes poor embryonic development ( 14 , 15 ). N-acetylcysteine (NAC), a precursor of reduced glutathione (GSH), is a well-known antioxidant.…”