Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Minas Gerais, Brazil.
Departamento de Clínica e Cirurgia Veterinárias, Escola de Veterinária, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, Minas Gerais, Brazil.
Theriogenology. 2024 Dec;230:21-27. doi: 10.1016/j.theriogenology.2024.09.001. Epub 2024 Sep 2.
Heat shock can impair embryo formation, while growth factors, such as colony-stimulating factor 2 (CSF2), modulate embryonic development. This study evaluated the effect of heat shock between days 2.5 and 3, as well as the impact of CSF2 at day 5 on bovine embryos cultured in a serum-free in vitro medium. The focus was on blastocyst development, the number of blastomeres, DNA fragmentation (TUNEL-positive cells), and mitochondrial activity. Heat shock reduced the proportion of cleaved embryos that developed into blastocysts (P = 0.0603). The resultant blastocysts exhibited a reduced number and proportion of TUNEL-positive cells in the trophectoderm (P = 0.0270 and P = 0.0240, respectively) and in the entire embryo (P = 0.0029 and P = 0.0031, respectively). Additionally, mitochondrial activity was lower in blastocysts derived from heat-shocked embryos (P = 0.0150) and further reduced in embryos exposed to both heat shock and CSF2 (P = 0.0415). In conclusion, the exposure of cleaved embryos to heat shock reduced their development to the blastocyst stage. However, the resulting blastocysts showed decreased DNA fragmentation and mitochondrial activity.
热休克会损害胚胎形成，而生长因子（如集落刺激因子 2 [CSF2]）则调节胚胎发育。本研究评估了在第 2.5 天至第 3 天之间进行热休克以及在第 5 天添加 CSF2 对在无血清体外培养基中培养的牛胚胎的影响。重点是研究囊胚发育、卵裂球数量、DNA 片段化（TUNEL 阳性细胞）和线粒体活性。热休克降低了从卵裂期胚胎发育为囊胚的比例（P=0.0603）。所得囊胚的滋养外胚层（P=0.0270 和 P=0.0240）和整个胚胎（P=0.0029 和 P=0.0031）中 TUNEL 阳性细胞的数量和比例降低。此外，来自热休克胚胎的囊胚中的线粒体活性较低（P=0.0150），而同时暴露于热休克和 CSF2 的胚胎中的线粒体活性进一步降低（P=0.0415）。总之，将卵裂期胚胎暴露于热休克会降低其发育为囊胚的能力。然而，由此产生的囊胚显示出 DNA 片段化和线粒体活性降低。
