Objectives: To investigate the effects of plasma from the patients with preeclampsia on proliferation and apoptosis of human umbilical vein endothelial cells (HUVEC), and to explore the relationship between cell damage and lysophosphatidic acid (LPA) receptors.
Methods: Sixty patients with preeclampsia were recruited from October 2011 to June 2012 in the First Affiliated Hospital of Zhengzhou University. Among them, thirty cases were defined as the mild preeclampsia group and thirty cases were defined as the severe preeclampsia group. The other thirty healthy pregnant women were recruited in the healthy pregnant women group. The levels of plasma LPA in the three groups were measured. The HUVEC were cultured in vitro with plasma from the three groups, and a blank control group was set up as well. Proliferation and apoptosis of HUVEC were measured by MTT assay and flow cytometry. Immunohistochemistry of biotin streptomyces protein peroxidase (SP) method was used to measure the protein expression level of Edg 2, 4, 7.
Results: (1) The plasma LPA levels in the healthy pregnant woman group, mild preeclampsia group and severe preeclampsia group were (3.38 ± 2.08) µmol/L, (6.12 ± 0.22) µmol/L, (9.10 ± 0.17) µmol/L, respectively. The plasma levels of LPA in patients with preeclampsia were significantly higher than that in the healthy pregnant women (P < 0.01). (2) The proliferation rate of HUVEC in the mild and severe preeclampsia groups [(65.2 ± 2.7)% and (51.9 ± 2.8)%] were significantly lower than that in the healthy pregnant women group and the control group [(84.3 ± 3.1)% and (100.0 ± 0.0)%, P < 0.01]. (3) The early apoptosis rate, middle-late apoptosis rate and total apoptosis rate of HUVEC in the mild and severe preeclampsia groups [total apoptosis rate were (30.4 ± 2.0)% and (43.4 ± 2.5)%] were significantly higher than those in the healthy pregnant women group and the control group [total apoptosis rate were (18.6 ± 1.6)% and (8.0 ± 1.5)%, P < 0.01]. (4) The expression positive rates of Edg 2, 4, 7 proteins in the four groups were as following: mild preeclampsia group 83%, 80% and 73%; severe preeclampsia group 97%, 93% and 90%; healthy pregnant women group 40%, 40% and 37%, and the control group 10%, 10% and 7% respectively. The positive rates of HUVEC in the mild and severe preeclampsia groups were significantly higher than those in the healthy pregnant women group and the control group (P < 0.01).
Conclusions: The plasma of patients with preeclampsia could inhibit proliferation and promote apoptosis of HUVEC, and induce the expression of Edg 2, 4, 7 proteins. It suggested that the increase of lysophosphatidic acid in plasma could be one of the reasons of endothelial cell damage in patients with preeclampsia.