Correlation between the levels of miR-21, miR-34c, miR-140 and miR-375 in the sperm from in vitro fertilization patients and the embryo quality

Abstract

To explore the correlation between sperm-originated miRNAs and embryo quality by detecting the expression levels of miR-21, miR-34c, miR-140 and miR-375 in the sperm from in vitro fertilization (IVF) patients. The fresh semen specimens were collected from 44 male patients who received the IVF cycle in the Xiangya Hospital Reproductive Center from September to December in 2012. The expression levels of miR-34c, miR-140, miR-21 and miR-375 were detected by real-time fluorescent quantitative PCR. The embryos on day 2 and day 3 after fertilization were divided into the experimental and the control group, with an average embryo scores less or greater than 8, respectively. Then we compared the general and experimental data between the 2 groups respectively and analyzed the correlation between the miRNAs levels in sperm and embryo quality. The expression of miR-34c, miR-140, miR-21 and miR-375 in sperms from the experimental group was significantly lower than that in the control group (P<0.05). There was no significant difference in retrieved follicles, metaphase II stage ovocytes, fertilized oocytes, cleavage number and fertilization rate between the experimental group and the control group (P>0.05), while the cleavage rate on day 2 in the experimental group was significantly lower than that of the control group (P<0.05). There was a negative correlation between the expression levels of miRNAs (miR-21, miR-34c, miR-140 and miR-375) and the ratio of fragment on day 2 or day 3. The expression levels of miR-21, miR-34c, miR-140 and miR-375 was positively correlated with the embryo score and the blastomere quantity on day 3, respectively. The up-regulated levels of miR-21, miR-34c, miR-140 and miR-375 in sperm may function as positive regulators in the development of cleavage stage in embryo and thus influence embryonic quantity.