Yunnan Provincial Engineering Laboratory of Animal Genetic Resource Conservation and Germplasm Enhancement, Yunnan Animal Science and Veterinary Institute, Kunming, Yunnan, 650224, China.
College of Veterinary Medicine, Yunnan Agricultural University, Kunming, Yunnan, 650201, China.
Theriogenology. 2021 Jun;167:13-23. doi: 10.1016/j.theriogenology.2021.03.006. Epub 2021 Mar 9.
As one of the most powerful natural antioxidants, astaxanthin (Ax) has begun to be applied to the field of reproductive biology. Here we used porcine oocyte as a model to explore how Ax improves the oocyte potential during in vitro maturation (IVM), and we also investigated the cytoprotective effects of Ax on the vitrified oocytes. Ax supplementation (final concentration of 2.5 μM) was subjected for immature oocytes during vitrification and subsequent IVM; fresh oocytes were also matured in vitro in the presence or absence of 2.5 μM Ax. Our results showed that Ax significantly increased the survival rate of vitrified oocytes, and promoted the blastocyst yield of both fresh and vitrified oocytes after parthenogenetic activation and somatic cell nuclear transfer. The oocytes treated with Ax displayed significantly lower reactive oxygen species generation and higher glutathione level. Vitrification of oocytes had no impact on caspase-3, cathepsin B and autophagic activities; Ax significantly decreased the cathepsin B activity in both fresh and vitrified oocytes. Moreover, the relative fluorescence intensity of lysosomes was significantly increased in vitrified oocytes, which was recovered by Ax treatment. The mitochondrial activity did not differ between fresh and vitrified oocytes, and was significantly enhanced in Ax-treated oocytes. Furthermore, Ax significantly restored the decreased expression of BMP15, ZAR1, POU5F1, GPX4 and LAMP2 genes in vitrified oocytes. Both fresh and vitrified oocytes treated with Ax showed significantly higher mRNA levels of GDF9, POU5F1, SOD2, NRF2 and ATG5. Taken together, this study provides new perspectives in understanding the mechanisms by which Ax improves the developmental competence of both fresh and vitrified porcine oocytes.
虾青素（Ax）作为一种最强大的天然抗氧化剂之一，已开始应用于生殖生物学领域。在这里，我们以猪卵母细胞为模型，探讨了 Ax 如何在体外成熟（IVM）过程中提高卵母细胞的潜能，并且还研究了 Ax 对玻璃化卵母细胞的细胞保护作用。在玻璃化和随后的 IVM 过程中，将 Ax（终浓度为 2.5 μM）添加到未成熟卵母细胞中；新鲜卵母细胞也在存在或不存在 2.5 μM Ax 的情况下在体外成熟。我们的结果表明，Ax 显著提高了玻璃化卵母细胞的存活率，并促进了孤雌激活和体细胞核移植后新鲜和玻璃化卵母细胞的囊胚产率。用 Ax 处理的卵母细胞显示出明显较低的活性氧生成和较高的谷胱甘肽水平。玻璃化对卵母细胞中的 caspase-3、组织蛋白酶 B 和自噬活性没有影响；Ax 显著降低了新鲜和玻璃化卵母细胞中的组织蛋白酶 B 活性。此外，玻璃化卵母细胞中的溶酶体相对荧光强度明显增加，Ax 处理可恢复该强度。新鲜和玻璃化卵母细胞的线粒体活性没有差异，并且在 Ax 处理的卵母细胞中显著增强。此外，Ax 显著恢复了玻璃化卵母细胞中 BMP15、ZAR1、POU5F1、GPX4 和 LAMP2 基因表达的降低。用 Ax 处理的新鲜和玻璃化卵母细胞的 GDF9、POU5F1、SOD2、NRF2 和 ATG5 的 mRNA 水平均显著升高。总之，这项研究为理解 Ax 提高新鲜和玻璃化猪卵母细胞发育能力的机制提供了新的视角。
