Abstract：
There is still no consensus regarding the role of lipid modulators during in vitro embryo production. Thus, we investigated how lipid reducers during the in vitro maturation of oocytes (IVM) or in vitro culture (IVC) of embryos impact their cryotolerance. A literature search was performed using three databases, recovering 43 articles for the systematic review, comprising 75 experiments (13 performed in IVM, 62 in IVC) and testing 13 substances. In 39 % of the experiments, an increase in oocyte and/or embryo survival after cryopreservation was reported, in contrast to 48 % exhibiting no effect, 5 % causing negative effects, and 8 % influencing in a dose-dependent manner. Of the 75 experiments extracted during IVM and IVC, 41 quantified the lipid content. Of those that reduced lipid content (n = 26), 50 % increased cryotolerance, 34 % had no effect, 8 % harmed oocyte/embryo survival, and 8 % had different results depending on the concentration used. Moreover, 28 out of the 43 studies were analyzed under a meta-analytical approach at the IVC stage in cattle. There was an improvement in the cryotolerance of bovine embryos when the lipid content was reduced. Forskolin, l-carnitine, and phenazine ethosulfate positively affected cryotolerance, while conjugated linoleic acid had no effect and impaired embryonic development. Moreover, fetal bovine serum has a positive impact on cryotolerance. SOF and CR1aa IVC media improved cryotolerance, while mSOF showed no effect. In conclusion, lipid modulators did not unanimously improve cryotolerance, especially when used in IVM, but presented positive effects on cryotolerance during IVC when reaching lipid reduction.
摘要：
关于脂质调节剂在体外胚胎产生过程中的作用仍然没有共识。因此，我们研究了卵母细胞体外成熟(IVM)或胚胎体外培养(IVC)过程中的降脂剂如何影响其低温耐受性.使用三个数据库进行文献检索，为系统评价收回43篇文章，包括75个实验(13个在IVM中进行，IVC中为62），并测试了13种物质。在39%的实验中,据报道，冷冻保存后卵母细胞和/或胚胎存活率增加，相比之下，48%的人没有效果，5%造成负面影响，8%的影响呈剂量依赖性。在IVM和IVC期间提取的75个实验中，41定量脂质含量。在那些降低脂质含量的人中（n=26），增加50%的低温耐受性，34%没有效果，8％的卵母细胞/胚胎存活受损，和8%有不同的结果取决于使用的浓度。此外，43项研究中的28项在牛的IVC阶段采用荟萃分析方法进行了分析。当脂质含量降低时，牛胚胎的低温耐受性有所改善。Forskolin,左旋肉碱,和吩嗪硫酸乙酯对低温耐受性有积极影响，而共轭亚油酸对胚胎发育没有影响。此外，胎牛血清对低温耐受性有积极影响。SOF和CR1aaIVC培养基提高了低温耐受性，而mSOF没有效果。总之,脂质调节剂并没有一致提高低温耐受性，特别是在IVM中使用时，但在IVC达到降脂时对冷冻耐受性有积极影响。
