This study addresses the hypothesis that SIRT1 upregulation prior to cryopreservation helps in recuperation from cryoinjury and improves the embryo quality. Bovine blastocysts were produced in vitro, and at Day 6 or 7 after fertilization, the blastocysts were cultured with 0 or 1 μM resveratrol for 6 or 24 h. This short duration of resveratrol treatment did not affect the embryo development or the grade of the blastocysts. However, both the durations of resveratrol treatment (6 h or 24 h) significantly increased the expression levels of SIRT1. When embryos pre-treated with resveratrol (0 or 1 μM) were cryopreserved and subsequently thawed, the hatching rates following 48 h of incubation were significantly higher for the resveratrol-treated embryos than for vehicle-treated embryos. Moreover, the resveratrol pretreatment significantly increased the copy number of mitochondrial DNA in the embryos, irrespective of the treatment durations. The in vitro-produced embryos at 6 days of insemination and the in vivo-developed embryos, which were collected from the donor cows at 6.5 days of insemination, were treated with resveratrol for 6 or 24 h prior to cryopreservation, respectively. The resveratrol pretreatment (for 6 or 24 h) resulted in high conception rate after thawing and transfer to the recipients, in both the in vivo and in vitro-produced embryos. In conclusion, our results suggest that pretreatment of bovine embryos with resveratrol improves the quality of embryos after cryopreservation and thawing probably through mitochondrial synthesis.
Keywords: Bovine; Conception; Embryo; Mitochondrial DNA; Resveratrol.
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