Expression And Significance Of Hypoxia Inducible Factor-2α(HIF-2α) In Normal Pregnancy And Preeclampsia Placenta

Objective To investigate the expression and significance of hypoxia inducible factor-2α (HIF-2 α) in preeclampsia placenta and in normal pregnancy placenta .Method Semi-quantitative RT-PCR and immunohistochemistry were used to detect the expression of HIF-2 α mRNA and protein in placenta of 30 patients with preeclampsia(11 cases of mild and 19 cases of severe preeclampsia,preeclampsia group) and 37 cases of normal pregnancy (control group).Result (1) The expression of HIF-2α mRNA in placenta was significantly lower of the first trimester group than that of the third trimester group (t=3.11;P<0.01);butthe differences were not significant between the second trimester group and the third trimester group (t=1.739;P>0.05) ,same between the first trimester group and the second trimester group (t=1.33;P>0.05) . There were also no significant differences (P>0.05) between the preeclampsia group and the third trimester group , and between the severe group and the mild group. (2) The mean density of HIF-2α protein in normal pregnancy placenta was not significant between the second trimester group and the third trimester group (t=0.75;P>0.05) . But the differences were significant between the first trimester group and the third trimester group (t=4.375;P<0.01) , and between the first trimester group and the second trimester group (t=4.359;P < 0.01) ,respectively.The mean density of HIF-2α protein in preeclampsia placenta(0.172±0.011) was significantly higher than that in the third trimester group(0.155±0.009;P<0.01) and the severe group(0.176± 0.010) was higher than the mild group (0.166±0.010;P<0.05) . (3) There was a positive correlation between the level of HIF-2α in placenta and the 24-hour urinary protein in women with preeclampsia(r=0.517, P<0.01), there was no correlation with HIF-2 α mRNA (r=0.247, P>0.05 ) .(4) The HIF-2 a expression in preeclampsia placenta was significantly increased in IUGR group, compared with the group of NIUGR (P<0.01).There was no significant difference on the level of HIF-2α mRNA( P>0.05).(5) The levels of HIF-2 a and HIF-2α mRNA in preeclampsia placenta both had no significant differerce between the group with the onset before 32 gestation weeks and the group with the onset after 32 gestation weeks( P>0.05).Conclusion (1) HIF-2α plays a role in the placenta's development process of normal pregnancy. (2) HIF-2α in placenta participites the pathophysiological processes ofpreeclampsia in the protein level.(3) The level of HIF-2 a in the preeclampsia group was significantly higher than the normal pregnancy group and correlated closely with the severity of the desease. (4)The expression of HIF-2 a in preeclampsia placenta is important for maintaining fetal development,but there is no correlation between HIF-2 a and the time of onset.