Xu Hongxia, Jia Chao, Cheng Wenxiu, Zhang Tongtong, Tao Ruixin, Ma Yuehua, Si Linan, Xu Yinxue, Li Juan
College of Animal Science and Technology, and Nanjing Agricultural University, Nanjing, China.
College of Horticulture, Nanjing Agricultural University, Nanjing, China.
Cell Reprogram. 2020 Aug;22(4):198-207. doi: 10.1089/cell.2020.0014. Epub 2020 Jul 14.
Cryopreservation of oocytes/embryos is an important technique for genetic resources; however, the success of vitrification in pig oocytes remained at a relatively lower level due to the high content of lipid droplets (LDs). Considering the positive effect of L-carnitine on the function of LDs, the present study was designed to investigate the effect of the addition of L-carnitine on the vitrification of porcine cumulus cells of complexes (cumulus/oocyte complexes [COCs]). First, COCs were randomly divided into two groups: one group of COCs were commonly maturation (IVM) for 42-46 hours (nonvitrification [NV]), while another group of COCs were IVM with 10 mM L-carnitine (NVL [nonvitrification with L-carnitine addition in IVM]). In addition, random parts of COCs with L-carnitine addition were vitrified (VL [vitrification with L-carnitine addition in IVM]), while vitrification was performed on COCs without L-carnitine used as control group (V). Results showed that the maturation rate of pig oocytes reduced significantly when the vitrification was performed at 16 hours during IVM (VL vs. NVL, 40.09 ± 2.85 vs. 90.76 ± 1.16; V vs. NV, 34.41 ± 2.55 vs. 89.71 ± 1.33, < 0.01). With the addition of L-carnitine, intracellular LDs were decreased significantly ( < 0.01). However, no difference was observed on the efficiency of vitrification in pig oocytes (VL vs. V, 40.09 ± 2.85 vs. 34.41 ± 2.55, > 0.05). In addition, not only the reactive oxygen species (ROS) level in pig oocytes with the L-carnitine addition group reduced significantly ( < 0.01), but also the expression of gene was improved ( < 0.05). In conclusion, results demonstrated that although no difference could be observed on pig COC vitrification, the LDs and ROS level in pig oocytes could be modified by the addition of L-carnitine, which might be helpful for further development.
卵母细胞/胚胎的冷冻保存是一种重要的遗传资源技术；然而，由于脂滴（LDs）含量高，猪卵母细胞玻璃化的成功率仍处于相对较低水平。考虑到左旋肉碱对脂滴功能的积极作用，本研究旨在探讨添加左旋肉碱对猪卵丘细胞复合体（卵丘/卵母细胞复合体[COCs]）玻璃化的影响。首先，将COCs随机分为两组：一组COCs常规体外成熟（IVM）42 - 46小时（非玻璃化[NV]），而另一组COCs在10 mM左旋肉碱存在下进行IVM（NVL[IVM中添加左旋肉碱的非玻璃化]）。此外，将添加左旋肉碱的COCs随机抽取部分进行玻璃化（VL[IVM中添加左旋肉碱的玻璃化]），而对不添加左旋肉碱的COCs进行玻璃化作为对照组（V）。结果表明，在IVM的16小时进行玻璃化时，猪卵母细胞的成熟率显著降低（VL组与NVL组，40.09±2.85对90.76±1.16；V组与NV组，34.41±2.55对89.71±1.33，P<0.01）。添加左旋肉碱后，细胞内脂滴显著减少（P<0.01）。然而，在猪卵母细胞的玻璃化效率上未观察到差异（VL组与V组，40.09±2.85对34.41±2.55，P>0.05）。此外，不仅添加左旋肉碱组猪卵母细胞中的活性氧（ROS）水平显著降低（P<0.01），而且基因表达也得到改善（P<0.05）。总之，结果表明，虽然在猪COC玻璃化方面未观察到差异，但添加左旋肉碱可改变猪卵母细胞中的脂滴和ROS水平，这可能有助于进一步发育。
