OBJECTIVETo evaluate the effect of carbon disulfide (CS2) exposure during the peri-implantation period on the levels of calcitonin (CT) and progesterone (P4) in the uterus of pregnant mice and to investigate the mechanism of embryo loss induced by CS2 exposure during the peri-implantation period.

METHODSA total of 168 healthy pregnant Kunming mice were randomly assigned to receive an intraperitoneal injection of CS2 (631.4 mg/kg) or olive oil (control) on gestational day (GD) 3, GD4, GD5, or GD6. The experiment was completed at different end points (GD4, GD5, GD6, GD7, and GD9). The levels of CT and P4 in the uterus were measured by enzyme-linked immunosorbent assay at each end point.

RESULTSThe numbers of implanted embryos in GD3, GD4, GD5, and GD6 exposure groups significantly decreased by 42.85%, 63.74%, 60.45%, and 47.26%, respectively,compared with those in control group (P < 0.01). The GD3, GD4, GD5, and GD6 exposure groups had significantly decreased CT levels at each end point (P < 0.05), and the GD3, GD4, and GD5 exposure groups had significantly decreased P4 levels (P < 0.05). In the GD3, GD4, GD5, and GD6 exposure groups, the number of implanted embryos was positively related with the levels of CT and P4 expressed in the uterus (r = 0.670, P < 0.01; r = 0.632, P < 0.01); the expression level of CT was positively related with that of P4 in the uterus of pregnant mice (r = 0.325, P < 0.01).

CONCLUSIONExposure to CS2 during the peri-implantation period can reduce the expression levels of CT and P4 in the uterus of pregnant mice, which might be one of the molecular mechanisms of embryo loss induced by CS2 exposure.