microRNAs in early pregnant porcine endometrium revealed by Illumina sequencing. Sus scrofa

Preimplantational estrogen exposure to pregnant gilts has been associated with implantation failure, embryonic losses and changes in endometrial mRNA expression. Small non-coding RNAs (ncRNA), especially miRNAs, play a key role in regulation of gene expression. Effects of estrogens on endometrial microRNAs (miRNA), however, have not been investigated in this context so far. Thus, we studied the influence of estradiol-17β (E2) on the endometrial expression profile of miRNAs in the pig at gestational day 10. E2 administered early during pregnancy resulted in significantly higher endometrial estrogen concentrations even at a low dose, but did not disrupt the expression profile of endometrial miRNAs. Overall design: Starting at insemination, sows were fed E2 at either 0.05, 10 and 1000 μg E2/kg body weight/day, respectively, or ethanol carrier only until examination at day 10 of pregnancy. 4 samples per treatment group were analyzed by high throughput sequencing (in the lowest dose group, tissue from one sow was extracted twice represeting a biological replicate).