Endometrial Factors Causing Subfertility in Cows

Abstract An inadequate uterine environment is believed to promote embryonic mortality and to result in reproductive failure. We conducted global endometrial gene expression analyses in fertile and subfertile cows to investigate the cause of reproductive failure. The gene expression pattern differed between fertile and subfertile cows; subfertile cows showed a greater number of highly expressed genes than the fertile cows. In particular, the genes encoding ribosomal proteins and mitochondrial oxidative phosphorylation were found among the more highly expressed genes in subfertile cows. The mitochondrial DNA copy number was significantly higher in the endometrium of subfertile cows, whereas the ATP content did not differ between fertile and subfertile cows. Quantitative RT-PCR analysis demonstrated that the expression of BCL2L13 was significantly lower in subfertile cows than that in fertile cows. These results suggest that cellular senescence occurs in the endometrium and causes poor-quality mitochondria to accumulate there by reducing mitophagy in subfertile cows. Administration of resveratrol into the uteri of subfertile cows partially increased endometrial BCL2L13 mRNA levels, decreased mitochondrial DNA copy numbers, and allowed for conception following embryo transfer. Collectively, these results suggest that decreased mitophagy in the endometrium of subfertile cows may contribute to infertility.