Objective: To investigate the expression of heme oxygenase-1 (HO-1) and heme oxygenase-2 (HO-2) in placenta tissue of pregnancy induced hypertension (PIH), and the relationship between HO protein expression and enzymatic activity.
Methods: Protein expression was analyzed qualitatively and semi-quantitatively by Western blotting in placental tissue of PIH (PIH group, n = 30) and normal late pregnant women (control group, n = 30). The levels of HO enzymatic activity in placental tissue were measured with the double wavelength scanning by spectrophotometer.
Results: (1) Western blotting analysis demonstrated that the relative protein levels of HO-1 and HO-2 in placental samples of control group were 0.7 +/- 0.4 and 0.8 +/- 0.4 respectively, there were no significant difference between HO-1 and HO-2 protein levels (P > 0.05). (2) The relative levels of HO-1 were 0.6 +/- 0.4 in PIH group, there was no significant difference from those in the control group (P > 0.05); the relative levels of HO-2 protein were 0.6 +/- 0.3 in PIH group, that were obviously lower than those in the control group (P < 0.01). The levels of HO enzymatic activity of PIH group were (0.3 +/- 0.2) nmol x mg(-1) x h(-1), significantly lower than that of the control group [(0.5 +/- 0.3) nmol x mg(-1) x h(-1)] (P < 0.01). The levels of HO activity correlated with HO-2 protein levels.
Conclusions: The expression levels of HO-2 protein were decreased and HO enzymatic activity reduced in PIH group. HO may play a role in the pathophysiology of poor placental perfusion and tissue damage in placenta of PIH.