Poly(I:C) exposure during in vitro fertilization disrupts first cleavage of mouse embryos and subsequent blastocyst development.

The reproductive system can be infected by a variety of double-stranded RNA viruses, which disrupt ovary function and pregnancy. However, whether viral infection directly affects early embryonic development remains unknown. Here we show that Poly(I:C), which mimics a double-stranded RNA virus, significantly impaired mouse early embryonic development in vitro, and up-regulated TLR3 and IFNα at the two cells embryo stage. Further studies indicated that Poly(I:C)-treatment caused DNA damage and abnormal spindle morphology at the first cleavage. Moreover, CDX2 and SOX2 expression was decreased while blastocyst cell apoptosis was increased. Altogether, Poly(I:C) decreased the rate of successful in vitro fertilization via DNA damage and abnormal spindle morphology at the first cleavage and inhibited early embryonic development by inducing immune response and promoting blastocyst cell apoptosis. This study provides an implication for exploring the causes of reproductive disorders in mammals and humans caused by infection of double-stranded RNA virus.

Mild infection induced by low-dose LPS does not impair follicular development and is beneficial to pregnancy in mice.

The reproductive tract is susceptible to infection by a variety of bacteria, which can impair ovarian and uterine function. However, there is little known about whether mild infection can harm follicle development and embryo implantation. Here our results showed that the immune response to a mild infection simulated by low-dose LPS induced inflammatory factor IL-1b expression and decreased MMP2 expression involved in embryo implantation. LPS treatment also inhibited the ovulation process and reduced litter weight. Despite the immune response and the disturbed ovulation induced by treatment with low-dose LPS, the overall result was beneficial to mouse pregnancy. This research provides the necessary foundation for exploring the effects of mild bacterial infection on ovarian and uterine function in mammals.