Reproduction and Biotechnology Laboratory, Brazilian Agricultural Research Corporation (Embrapa), Juiz de Fora, Minas Gerais, Brazil.
Biology Department, Federal University of Juiz de Fora, Juiz de Fora, Minas Gerais, Brazil.
Reprod Domest Anim. 2021 Aug;56(8):1128-1136. doi: 10.1111/rda.13956. Epub 2021 Jun 8.
While microRNAs (miRNAs) are a class of non-coding RNAs important for embryo development, the relationship between them and heat stress during oocyte maturation has not yet been established. This study investigated the effect of heat shock during in vitro maturation (IVM) on the abundance of bta-miR-20a, -27b, -103, -21-5p, -19b, -1246 miRNAs and DROSHA and DICER1 mRNAs, previously reported for being involved in oocyte maturation, response to heat stress and miRNA biogenesis. Oocytes were exposed for 12h to heat shock during IVM, fertilized in vitro and the presumptive zygotes cultured for eight days. The relative quantification of miRNAs and mRNAs was performed by real-time PCR in vitro-matured oocytes and 8-cell stage embryos. Progression of meiosis, embryonic development and apoptotic indices was also evaluated. Heat shock compromised (p < .05) oocyte nuclear maturation, cleavage and embryo development, with a higher (p < .05) embryonic apoptotic index than the control group. The abundance of bta-miR-19b increased (p < .05) whereas the abundance of DROSHA transcripts decreased (p < .05) in embryos derived from heat-shocked oocytes. In conclusion, heat shock during IVM influences the abundance of bta-miR-19b and DROSHA in pre-implantation embryos, indicating a persistent effect of heat shock that can be associated with impaired embryo development.
虽然 microRNAs (miRNAs) 是一类在胚胎发育中起重要作用的非编码 RNA，但它们与卵母细胞成熟过程中的热应激之间的关系尚未确定。本研究探讨了体外成熟 (IVM) 期间热休克对先前报道参与卵母细胞成熟、热应激反应和 miRNA 生物发生的 bta-miR-20a、-27b、-103、-21-5p、-19b、-1246 miRNAs 和 DROSHA 和 DICER1 mRNAs 丰度的影响。在 IVM 期间，卵母细胞暴露于热休克 12 小时，体外受精，并在体外培养推定的受精卵 8 天。通过实时 PCR 在体外成熟的卵母细胞和 8 细胞阶段胚胎中对 miRNAs 和 mRNAs 的相对定量进行分析。还评估了减数分裂的进展、胚胎发育和凋亡指数。与对照组相比，热休克会损害（p <.05）卵母细胞核成熟、卵裂和胚胎发育，胚胎凋亡指数更高（p <.05）。源自热休克卵母细胞的胚胎中 bta-miR-19b 的丰度增加（p <.05），而 DROSHA 转录物的丰度降低（p <.05）。总之，IVM 期间的热休克会影响植入前胚胎中 bta-miR-19b 和 DROSHA 的丰度，表明热休克的持续影响可能与胚胎发育受损有关。
