Abstract: ［Abstract］ Objective〖HTSS〗〓To observe the effect of cyclosporine A on rats with preeclampsia(PE), and to explore its mechanism by determining the influence of cyclosporine A on the immune status, placenta oxidant stress and nitric oxide(NO) in rats with preeclampsia.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓A total of 30 rats were randomly divided into 3 groups(10 in each group): the control group, the PE group and the treatment group. The rats in the PE group and the treatment group received lowdose endotoxin to establish the PE models. The rats in the treatment group received intraperitoneal injection of cyclosporine A on the 15 th, 16 th, 17 th, 18 th gestation days. Blood pressure and 24 hour urine protein were determined on the 14 th and the 19 th gestation days, respectively. Rats were all sacrificed on the 20 th gestation day. Serum levels of IL6, TNFα and TNFγ were determined by ELISA and the ratio of blood CD4+CD25+FoxP3+Treg cells to CD4+ cells were tested with flowcytometry. Activity of reactive oxygen species （ROS）, malondialdehyde (MDA) and NO levels in the placenta tissue were respectively determined.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓On the 19 th gestation day, the blood pressure and 24 hour urine protein in the treatment were both significantly decreased compared with the PE group(P＜001). On the 20 th gestation day, when compared to the PE group, the placenta weight, weight of the fetal rat and the ratio of blood CD4+CD25+FoxP3+Treg cells to CD4+ cells were all significantly decreased, while the serum levels of IL6, TNFα and TNFγ, as well as the activity of ROS and the MDA level in the placenta tissue were significantly increased in the treatment group(P＜001).
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓Cyclosporine A can improve the perinatal outcome in rats with PE induced by endotoxin. The possible mechanism may lay in the inhibition of immune reaction and placenta oxidant stress, and the increasing level of NO by cyclosporine A.

Key words: preeclampsia, cyclosporine A, immunity, oxidant stress, nitric oxide