繁殖・生殖工学

[IV-20-13] Relationship between miRNA expression in intrauterine exosomes and fertility in cows

*市川 怜¹、東 誠也¹、中村 翔¹、大蔵 聡¹、木村 康二²、松山 秀一¹ (1. 名大院生命農、2. 岡山大院環境生命科研)

MicroRNAs (miRNAs) in intrauterine exosomes play roles in conceptus–maternal interactions before implantation. We hypothesized that miRNAs in the intrauterine exosomes of low-fertile cows would impair embryonic development and survival before implantation, resulting in infertility. In this study, the exosome intake by embryo was confirmed. Then, a small RNA-sequencing analysis was conducted using miRNAs from the intrauterine exosomes of normal and low-fertile cows 7 days after estrus. The expression levels of 8 miRNAs in low-fertile cows were significantly higher than in normal-fertile cows, of which miR-1 exhibited the highest expression levels (P = 0.08). To determine the timing of miRNA introduction into embryos by lipofection the fluorescent-labeled oligonucleotide was introduced into the blastocysts at each stage. The fluorescence was observed only in the hatched blastocyst. In summary, this study revealed that miR-1 in bovine intrauterine exosomes is associated with low fertility and established a lipofection method to transfer miRNA into embryos. Future studies will examine the effects of miR-1 on embryonic development and survival.