Laboratory of Reproductive Physiology, Department of Animal Production and Health, School of Veterinary Medicine, São Paulo State University (UNESP), Clóvis Pestana Street, 793, Araçatuba Campus, São Paulo, 16050-680, Brazil.
Graduate Program in Veterinary Medicine, Department of Animal Reproduction, School of Agrarian and Veterinary Sciences, São Paulo State University (UNESP), Campus Jaboticabal, São Paulo, Brazil.
Sci Rep. 2022 Jul 4;12(1):11228. doi: 10.1038/s41598-022-14688-8.
Giant unilamellar vesicles (GUVs) are composed of lipophilic layers and are sensitive to the action of reactive oxygen species (ROS). The use of GUVs as microcarriers of biological macromolecules is particularly interesting since ROS produced by gametes or embryos during in vitro culture can induce the opening of pores in the membrane of these vesicles and cause the release of their content. This study investigated the behavior of GUVs [composed of 2-dioleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl)] in co-culture with in vitro produced bovine embryos, as well as their embryotoxicity and effectiveness as cysteine carriers in culture medium. Embryonic developmental rates were unaffected, demonstrating the absence of toxicity of GUVs co-cultured with the embryos. No increase of intracellular ROS levels was observed in the embryos co-cultured with GUVs, indicating that the higher lipid content of the culture environment resulting from the lipid composition of the GUV membrane itself did not increase oxidative stress. Variations in the diameter and number of GUVs demonstrated their sensitivity to ROS produced by embryos cultured under conditions that generate oxidative stress. Encapsulation of cysteine in GUVs was found to be more effective in controlling the production of ROS in embryonic cells than direct dilution of this antioxidant in the medium. In conclusion, the use of GUVs in in vitro culture was found to be safe since these vesicles did not promote toxic effects nor did they increase intracellular ROS concentrations in the embryos. GUVs were sensitive to oxidative stress, which resulted in structural changes in response to the action of ROS. The possible slow release of cysteine into the culture medium by GUV rupture would therefore favor the gradual supply of cysteine, prolonging its presence in the medium. Thus, the main implication of the use of GUVs as cysteine microcarriers is the greater effectiveness in preventing the intracytoplasmic increase of ROS in in vitro produced bovine embryos.
巨大单层囊泡 (GUV) 由亲脂层组成,对活性氧物种 (ROS) 的作用敏感。将 GUV 用作生物大分子的微载体特别有趣,因为在体外培养过程中配子或胚胎产生的 ROS 可以诱导这些囊泡的膜上孔的打开,并导致其内容物的释放。本研究调查了在体外产生的牛胚胎共培养中 [由 2-二油酰基-sn-甘油-3-磷酸胆碱和 1,2-二油酰基-sn-甘油-3-磷酸乙醇胺-N-(lissamine rhodamine B 磺酰基)] GUV 的行为,以及它们的胚胎毒性和作为胱氨酸载体在培养基中的有效性。胚胎发育率不受影响,表明与胚胎共培养的 GUV 没有毒性。与 GUV 共培养的胚胎中未观察到细胞内 ROS 水平升高,这表明 GUV 膜本身的脂质组成导致培养环境中更高的脂质含量不会增加氧化应激。GUV 的直径和数量的变化表明它们对在产生氧化应激的条件下培养的胚胎产生的 ROS 敏感。发现将胱氨酸封装在 GUV 中比直接在培养基中稀释这种抗氧化剂更有效地控制胚胎细胞中 ROS 的产生。总之,在体外培养中使用 GUV 是安全的,因为这些囊泡既不会促进毒性作用,也不会增加胚胎细胞内的 ROS 浓度。GUV 对氧化应激敏感,这导致它们响应 ROS 的作用发生结构变化。因此,GUV 破裂可能会导致胱氨酸缓慢释放到培养基中,从而有利于胱氨酸的缓慢供应,延长其在培养基中的存在时间。因此,使用 GUV 作为胱氨酸微载体的主要意义在于在体外产生的牛胚胎中更有效地防止细胞质内 ROS 的增加。