Down-regulation of uterine LIF expression induced by the hormonal level disorder causes embryo implantation loss after mice exposed to carbon disulfide at peri-implantation.

Carbon disulfide (CS2) exposure can cause embryo implantation loss but the mechanism remains unclear. Earlier study revealed that the 4th day of gestation (GD4) and GD5 were the most sensitive exposure time on which the number of implanted embryos decreased obviously in mice. Leukemia inhibitory factor (LIF) in maternal uterine tissue is involved in embryo implantation, which is produced by endometrium and Th2 cells that participate in cellular adhesion of maternal-fetal interface. We herein investigated the effect of CS2 on the expression of LIF in uterine tissue and its regulatory mechanism in Kunming mice. Exposure was on GD3, GD4, GD5 and GD6, respectively, single administration (631.4 mg/kg), and the indexes were arranged in time series after exposure. The results showed that LIF gene breakage was captured at the 18th hour after exposure by Comet-FISH and the protein and mRNA of LIF in uterine tissue were down-regulated after exposure through the peri-implantation period. In addition, sex steroid hormones, progesterone (P4) and oestrogen (E2) were detected since they can stimulate synthesis of LIF from endometrial cells. Results showed that P4 and E2 in serum were down-regulated at all the endpoints of CS2 exposure groups. These findings suggested that the down-regulated LIF induced by the decreased P4 and E2 after mice exposure to CS2 might be important reasons for implantation disorders.