Instituto Nacional de Parasitología "M. F. Chaben" ANLIS Malbrán, Av. Paseo Colón 568, Ciudad de Buenos Aires, Argentina,
J Assist Reprod Genet. 2013 Oct;30(10):1377-88. doi: 10.1007/s10815-013-0060-8. Epub 2013 Aug 4.
Serum supplementation has shown to have beneficial effects on in vitro bovine embryo development. However, it is often assumed that serum supplementation may produce mitochondrial damage and this damage would generate lipid accumulation, a major obstacle for cryopreservation. The aim of the present study is to investigate the previous assumptions in early embryonic stages.
We considered in vitro produced bovine embryos from day 1 to 4 of development, which were grown in presence of serum from days 1, 2 or 3 or in absence of it. Electron transmission micrographs allowed us to quantify the area occupied by lipid droplets and by the different mitochondrial types to evaluate serum effect. Using confocal microscopy we analyzed mitochondrial activity and location.
We found no evidence of lipid droplets accumulation or mitochondrial degeneration or reduction of mitochondrial area in serum supplemented media. Further, our results suggest that events of mitochondrial proliferation are taking place even in serum supplemented media.
Serum does not produce lipid accumulation or mitochondrial damage in bovine embryos from 2 to 16 cells. When serum was added to embryo culture medium on day 3 of development, there were ultrastructural signs of a beneficial effect for embryo development. The lack of serum until day 3 may also avoid the unnecessary exposure to potentially inhibitory factors present on it.
血清补充已被证明对牛胚胎体外发育有有益的影响。然而，人们通常认为血清补充可能会产生线粒体损伤，这种损伤会导致脂质积累，这是冷冻保存的主要障碍。本研究的目的是在早期胚胎阶段调查先前的假设。
我们考虑了从第 1 天到第 4 天发育的体外生产的牛胚胎，这些胚胎在第 1、2 或 3 天存在血清或不存在血清的情况下生长。电子传输显微镜允许我们定量脂质滴和不同类型的线粒体的面积，以评估血清的作用。使用共聚焦显微镜分析线粒体的活性和位置。
我们没有发现血清补充培养基中脂质滴积累或线粒体退化或线粒体面积减少的证据。此外，我们的结果表明，即使在补充血清的培养基中，线粒体增殖事件也在发生。
血清不会在 2 到 16 细胞的牛胚胎中产生脂质积累或线粒体损伤。当在第 3 天的胚胎培养中添加血清时，胚胎发育有明显的有益作用。在第 3 天之前不使用血清也可以避免其不必要地暴露于其中存在的潜在抑制因子。
