| Pregnancy induced hypertension (PIH) is disorders during pregnancy, characterized by hypertension, proteinuria, reduced utero-placental circulation and endothelial cell dysfunction. It is a major cause of maternal death and contributes significantly to perinatal morbidity. Although the etiology of the hypertensive disorders in pregnancy is not completely understood, lipid peroxidation, poor placental perfution, local hypoxia, secretion of cytotoxic factors unbalance cited as main pathophysiology mechanisms associated with the disorder, but lack the compensatory mechanism to increased stress. Heme oxygenase (HO) catalyzes the oxidation of heme degradation to carbon monoxide(CO), biliverdin, and iron, is also involved in neurotransmission, inducement blood vessel relaxation, anti-inflammatory reaction, against oxidative damage, inhibition of platelet aggregation, playing a physiological role in cytoprotection against cell injury. Thus the aims of the study were to determine the expression, and localization of HO-l(inducible)and HO-2(constitutive) within the placenta of normal pregnancy and PIH, in addition, the effect of HO activation on tumor necrosis factor-alpha(TNF a )induced placental damage was studied, to provide the relationship between heme oxygenase expression and PIH.Part one Expression and tissue localization of hemeoxygenase in normal human first trimester and third trimester placenta.Methods: Reverse transcription polymerase chain reaction (RT-PCR) were resorted to demonstrate the expression of HO-1 and HO-2 in placenta tissues of normal human first trimester, obtained from 6-10 week gestation woman (20 cases) and the third trimester woman (20 cases). Protein expression was analyzed qualitatively and semi-quantitatively by Immuno-histochemistry.Result: Compared with GAPDH, the expression of HO-1 was lower, there was no significant difference between the first trimester 0.31±0.19 and third trimester 0.28 ± 0.14 (P>0.05); the expression of HO-2 was higher, it is significantly higher at third trimester 1.12 ± 0.58 compared with first trimester placenta 0.70?.48(P<0.05). The result of immuno-histochemistry demonstrated that HO-1 was predominantly localized in villous stroma cell and trophoblast. There was no significant difference between the staining of cell at first trimester and third trimester (P>0.05). HO-2 predominantly localized in trophoblast as well as capillaries, with weak staining of villous stroma. The staining of capillaries was higher at third trimester than first trimester ( P<0.05 ). There was no significant difference between the staining of trophoblast and villous stroma at first trimester and third trimester (P>0.05).Part two Hemeoxygenase expression and activity in human placenta of pregnancy induced hyertension.Method: Gene and Protein expression of HO-1 and HO-2 was analyzed qualitatively and. semi-quantitatively by RT-PCR and western blotting in placental tissue of PIH (PIH group, n=30) and normal late pregnancy woman (control group, n=30). The relative activity levels of HO enzymatic activity in placental tissue was measured with the bilrubin by the double wavelength scanning of spectrophotometer. Result: (l)RT-PCR analysis demonstrated that the relative mRNA amounts of HO-1 and HO-2 in placental samples of PIH group were 0.34±0.18 and 0.88 ± 0.57, there were no significant difference than those in control group 0.46 ± 0.30 and 0.87±0.28 (P>0.05); (2) Western blotting analysis demonstrated that the relative amounts of HO-1 and HO-2 inplacental samples of control group were 0.70 ± 0.42 and 0.83 ± 0.41 respectively, there were no significant difference between HO-1 and HO-2 protein levels (P>0.05). The relative amounts of HO-1 were 0.60 ± 0.41 in PIH group, there were no significant difference than those in the control group (P>0.05); the relative amounts of HO-2 protein were 0.59 ± 0.25 in PIH group, that were obviously decreased than those in the control group (P<0.0\). Among them, The relative amounts of mild PIH were 0.43 ± 0.43, no sig...
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