| Objective: Hypoxic pulmonary hypertension pulmonary arterial hypertension, PAH) is an important pathophysiological link in variety of heart and lung disease development. It is indicated that multiple factors were involved in the occurrence of PAH, and hypoxic pulmonary arterial hypertension(pulmonary arterial hypertension,HPAH) which produced by long-term chronic hypoxia has become a focus recently. Nitric oxide(nitric oxide, NO) produced by vascular endothelial cells plays an important role in maintaining the normal pulmonary vascular structure. Nitric oxide synthase(nitric oxide synthase, NOS) is the key enzymes to catalyze L-arginine(arginine, Arg) in body, so as to the important substances involved in regulating NO generation. The process of hypoxic pulmonary hypertension and vascular remodeling can be intervened by 17-2 beta estradiol(E2) and its metabolites- methoxy estradiol(EM) 2. This study aims to explore the impact of E2, 2ME to castration and hypoxic pulmonary hypertension rats by establishing long-term chronic hypoxic pulmonary hypertension rats model, and intervened by E2 and 2ME,to compare the content of NO and e NOS in rats’ serum to e NOS m RNA contented in rats’ lung tissue.Methods:1 Model building: A total of 80 healthy female Sprague-Dawdley( SD) rats were divided randomly into 8 groups(n=10 each) namely, sham group, ovariectomy group(OVX), OVX + E2 group, OVX+ 2ME group, sham + hypoxia group, OVX + hypoxia + E2 group,OVX + hypoxia + 2ME group and OVX + hypoxia group. The sham group were only opened the abdominal cavity of the rats and found the ovaries, which were not treated and directly returned. The OVX group were removed the bilateral ovaries: opened the abdominal cavity, found along the oviduct ovarian, ligation under the ovaries fallopian tubes and nutrient vessels, ovaries removed, close the abdominal cavity. The OVX+E2 group were removed the bilateral ovaries,and then received a subcutaneous injection of E2(20 μg· kg-1 · d-1). The OVX +2ME group were removed the bilateral ovaries,and then received a subcutaneous injection of 2ME(240 μg· kg-1 · d-1).The sham + hypoxia group were placed into an anaerobic tank after sham. The anaerobic tank 24 h continuous supply air and nitrogen gas atmospheric mixed gas, the oxygen concentration of oxygen box was controlled by oxygen monitoring control system(10±0.5)%.The OVX + hypoxia + E2 group were removed the bilateral ovaries,and then had a subcutaneous injection of E2(20 μg· kg-1 · d-1) and was placed into the anaerobic tank. The OVX + hypoxia + 2ME group were removed the bilateral ovaries,and then had received a subcutaneous injection of 2ME(240 μg· kg-1 · d-1) and was placed into the anaerobic tank. The OVX + hypoxia group were removed the bilateral ovaries,and then was placed into the anaerobic tank. All the 8 groups of healthy female Sprague-Dawdley( SD) rats feeding by the same methods were placed into the same room for 8 weeks.2 Observe the rat’s general situation and the status of pulmonary vascular involvement: General situation was observed daily, and weighed the rat’s body after 8weeks of feeding. Mean pulmonary artery pressure(m PAP) was measured by right-heart catheterize-tion, right ventricular hypertrophy index(RVHI) was calculated by the ratio of right ventricle to the left ventricle plus septum, and hypoxic pulmonary vascular remodeling(HPSR) was observed by microscope.3 The content of NO in serum of rats was measured by nitrate reductase method.4 The content of e NOS in rats’ serum was measured by chemical method.5 The content of e NOS m RNA in rat’s lung tissue was measured by RT-PCR.1 The general condition and weight of rats: With the experiment, after eight weeks, hypoxic rats box appears activities, eating less, gray coat, and with activity gradually reduced,the rats dominated reposed eventually, while death does not appear. The growth conditions and activity in rats under normoxic performanced good, and had no differences from the initial experiments. Compared with the sham group, the weight of rats of the sham + hypoxia group, OVX + hypoxia + E2 group and OVX + hypoxia + 2ME group growth slow(P<0.05), the weight of rats of the OVX + hypoxia group reduced significantly(P<0.01).While the OVX + E2 group and the OVX +2ME group had no significant difference in body weight.2 Compare the mean pulmonary arterial(m PAP):Compared with the sham group, the sham + hypoxia group, OVX + hypoxia + E2 group and the OVX + hypoxia + 2ME group obviously had a heigher m PAP(P<0.01),and although the m PAP of the OVX + hypoxia + E2 group and the OVX + hypoxia + 2ME group was increased, but it was lower than the sham + hypoxia group and the OVX + hypoxia group. There were no differences in the level of m PAP among the OVX + E2 group, the OVX + 2ME group and the shame group.3 Morphology changes in rat’s right ventricular morphological and pulmonary artery: In the light microscope, the distribution of rat pulmonary artery endothelial cells of the sham group, OVX + E2 group, OVX+ 2ME group, OVX group,was flat in a row, no edema and necrosis, pulmonary arterial wall morphology normal; while in the group of the OVX + hypoxia, pulmonary artery smooth muscle cells in the small(SMC) increased, the membrane thickening, and luminal narrowing. The pulmonary artery wall of the shame+ hypoxia group, OVX + hypoxia+ E2 group, OVX + hypoxia +2ME group were between the sham group and the OVX + hypoxia group. Compared with the sham group, right ventricular hypertrophy index that RV /(LV + SP) ratio of the sham + hypoxia group, OVX +hypoxia + E2 group, OVX + hypoxia+2ME group were significantly increased(P <0.01), and the OVX + hypoxia group increased the most(P <0.01), and the OVX + E2 group, Results: OVX+ 2ME group, OVX group had no significant difference in right ventricular hypertrophy index with the sham group.4 Changes in the content of NO in rats’ serum: Comparing with the sham group rats, the content of NO was significantly lower in rats of the sham + hypoxia group and OVX + hypoxia + E2 group(P<0.05),and the OVX +hypoxia group decreased most in NO contened in serum(P<0.01).The OVX + hypoxia+2ME group’s content of NO in serum was between the sham + hypoxia group, OVX+ hypoxia + E2 group and the OVX+ hypoxia group. Compared with the shame group, the OVX + E2 group, OVX + 2ME group and the OVX group showed no difference in terms of the content of NO in rats’ serum.5 Changes in the content of e NOS in rats’ serum: Compared with the sham group, the content of e NOS in the OVX + hypoxia +E2 group and the OVX + hypoxia+2ME group were significantly lower(P<0.05),and OVX + hypoxia group decreased most(P <0.01).Compared with the shame group, the sham+hypoxia group,the OVX + E2 group, OVX + 2ME group and the OVX group showed no difference in the content of e NOS.6 Compare the content of e NOS m RNA in rats’ lung tissue: Compared with the sham group, the content of e NOS m RNA in rats’ lung tissue in the OVX+hypoxia + E2 group and OVX + hypoxia + 2ME group was significantly lower(P <0.05), and the OVX+ hypoxia group reduced the most obvious(P <0.01).While the sham+hypoxia group,OVX + E2 group, OVX + 2ME group, and the OVX group had no significant differences from each other(see Table1).Conclusion:1 The content of NO in rats’ serum decreased obviously under hypoxic environment. Both rats with complete ovary and rats with E2 supplement can increase the level of NO content in serum. NO levels can also increased after 2ME supplemented, but the effect is less than E2 supplemented.2 The content of e NOS in rats’ serum reduced significantly under hypoxic environment. There were no difference between rats with complete ovary and rats fed in normoxia environment in terms of content of e NOS in rats’ serum.Also E2 and 2ME can be added to increase the content of e NOS in serum, and there were no significant differences between them too.3 The content changes of e NOS m RNA and e NOS in lung tissue had the same trend.4 Both E2 and 2ME can effectively reduced the hypoxic pulmonary hypertension, improved vascular remodeling hypoxic pulmonary hypertension and the same time inhibit right ventricular hypertrophy, suggesting that E2 and 2ME on e NOS / NO pathway has a synergistic effect. In addition, E2 might play more powerful role in terms of the content of NO. |
PDF Full Text Request