Sperm-carried RNAs play critical roles in mouse embryonic development

Recently, numerous studies have reported that the mature sperm contains both coding and non-coding RNAs and the sperm delivers some RNAs to the oocyte at fertilization. However, the functions of the RNAs carried to the oocyte by sperm at fertilization in embryonic development remains a mystery. In this study, the mature spermatozoa were treated with lysolecithin, pronase and RNases (RNase A and RNase H) to remove the sperm-carried RNAs, and then injected into normal mature oocyte. The results showed that after the treatment, the content of the sperm RNAs was decreased by about 90%. The blastocyst formation rate and the live birth rate of the embryos from intracytoplasmic sperm injection (ICSI) using the treated sperm were significantly decreased (P<0.01), while these effects were partially rescued by injecting total wide-type sperm RNAs. The reproductive capacity of offspring (F0) in sperm-treated group was similar with that in control group (P>0.05), but the body weight of F1 mice from sperm-treated group was lower than that in control group after two weeks of birth (P<0.05). These results demonstrated that the sperm-carried RNAs have important roles in embryonic development.