Abstract:

Objective To investigate the expression of hypoxia-inducible factor prolyl 4-hydroxylase (HPH) in placentas of normal pregnant women and patients with pre-eclampsia, and explore the relationship between oxygen sensitivity of trophoblast and hypoxia in preeclamptic placenta. Methods Sixty-six pregnant women undergoing cesarean section or family planning surgery were divided into early pregnancy group (n=13), mid-pregnancy group (n=9), late pregnancy group (n=13, controls for pre-eclampsia group and gestational hypertension group), pre-eclampsia group (n=20) and gestational hypertension group (n=11). The expression of HPH-1, HPH-2 and HPH-3 mRNA in placentas and villous tissues was determined by in situ hybridization and Real-Time PCR. Results HPH-1, HPH-2 and HPH-3 mRNA was mainly expressed in cytoplasm of trophoblast, and HPH-1 mRNA was significantly expressed in cytoplasm of extravillous trophoblast. With the progress of pregnancy, the expression of HPH-1 mRNA significantly increased (r=0.616, P<0.001). The expression of HPH-1 mRNA in pre-eclampsia group was significantly lower than that in late pregnancy group (P<0.05). The expression of HPH-1 mRNA in gestational hypertension group was also lower than that in late pregnancy group, while there was no significant difference between them (P>0.05). The weight of placentas in pre-eclampsia group was significantly related to the expression of HPH-1 mRNA (r=0.457, P<0.05). Conclusion Low oxygen sensitivity of trophoblast (low expression of HPH-1 mRNA) may be an important cause for placenta hypoxia (overactivation of hypoxia reaction pathway) in patients with pre-eclampsia.

Key words: pre-eclampsia, hypoxia-inducible factor prolyl 4-hydroxylase, trophoblast