Differential expression of miR-145, miR-429 and its target genes in partial reproductive tissues of swine with high and low litter size

To justify the function of miRNAs in reproductive regulation in swine, the expression of miR-145, miR-429 and their related genes were studied in reproductive tissues of sows. Wannan black pig and Yorkshire pigs with extremely high (n=6) and low (n=6) litter size were sampled, and real-time quantitative PCR (qPCR) was performed on tissue samples from ovaries, uterus, oviduct, hypothalamus, and pituitary. The results indicated that miR-145, miR-429, and zinc finger E-box binding homeobox 1 gene (ZEB1) were expressed significantly different in Wannan black pig and Yorkshire pigs. In pigs with different fecundity, miR-145 in the uterus was expressed significantly lower in pigs with high litter size, than in pigs with low litter size. The miR-429 expression in the oviduct and pituitary of pigs with high litter size was significantly higher compared with tissues sampled from pigs with low litter size. The ZEB1 expression in the pituitary was lower in pigs with high litter size in comparison to pigs with low litter size, while luteinizing hormone beta subunit (LHβ) showed the opposite pattern of expression. In conclusion, miR-145 and miR-429 were differently expressed in pigs with high and low litter size and might have a role in affecting litter size of sows.