The Research Of The Relationship Between 17beta-Estradiol, 2-Methoxyestradiol And Endothelin-1 As Well As Its Receptor In Chronic Hypoxic Pulmonary Hypertension Rats

Objective: Pulmonary hypertension is pulmonary vascular remodeling disease.which characterized by pulmonary small vascular endothelial cells, smooth muscle cell proliferation, migration, apoptosis resistance, gradually lead to pulmonary vascular wall thickening and lumen occlusion. Endothelin-l(endothelin-l, ET-l) may be a strong contraction of blood vessels peptides, is newly studied more closely related to pulmonary vascular remodeling,A significant rise in the pulmonary artery in patients with PAH, and is closely related to the severity and prognosis of PAH, ET-1 is mainly synthetic of pulmonary vascular endothelial cells, but the pulmonary vascular SMC also has the ability to synthesis and secretion of ET-1. And By he ETAR and ETBR in a paracrine or autocrine effects on vascular endothelial cells and SMC, which jointly adjust the systolic and diastolic function of blood vessel, Estrogen(Estradiol, E2) in pulmonary vascular system protection, it can reduce the damage to a variety of causes of pulmonary vascular endothelial cells and smooth muscle cell function, To improve vascular remodeling and diastolic blood vessels, but the specific mechanism has not yet fully understood. This study aims to through the establishment of chronic hypoxic pulmonary hypertension rats model, To research endothelin-1 and its receptor’s expression in the lung tissue, To the discuss the effects of endothelin 1, endothelin receptor in rat in the process of primary pulmonary hypertension disease and 2- methoxy estradiol estrogen and its metabolites on the effect of endothelin-1 and its receptor.Method:1 Model building and grouping: eightty SD rats were divided randomly into A sham operation group, B OVX+E2 group,C OVX+2ME group, D ovariectomy(OVX) group,E Hypoxia group, F OVX+ Hypoxia+E2 group, G OVX+ Hypoxia+2ME group,H OVX+Hypoxia group. Group Aand E only open the abdominal cavity, and then suture.group B、C and F、G were opened the abdominal cavity, found along the oviduct ovarian, ovaries removed, close the abdominal cavity, U suture of the skin,then were given E2 20g/kg/d, 2- methoxy estradiol 240 g/kg/d subcutaneous injection. group D and H were opened the abdominal cavity, found along the oviduct ovarian, ovaries removed, close the abdominal cavity, U suture of the skin. the rats of group E.E.G.H were placed in the hypoxic chamber, the anaerobic tank 24 h continuous supply air and nitrogen gas atmosphericmixed gas, the oxygen concentration of oxygen box was controlled by oxygen monitoring control system(10±0.5)%, CO2 concentration less than 0.5%;All The rats were Normal feeding one week, after waiting for wound healing,then put them into the set environment.2 Long-term changes in hypoxic pulmonary hypertension rats: Meanpulmonary artery pressure(m PAP), was measured by right-heart catheterize-tion, right ventricular hypertrophy index(RVHI) was calculated by the ratio ofright ventricle to the left ventricle plus septum, and hypoxic pulmonaryvascular remodeling(HPSR) was observed by microscope.3 The content of ETA and ETB receptor m RNA expression in lung tissue was measured by RT-PCR.4 The content of ET-1 in the lung tissue protein levels was measured by radio-immunity assay.Results:1 The general condition of the rats: Eight weeks later, The rats under hypoxia appear dull color, Irish dark red, shortness of breathing, eating less, with The hypoxia time prolonged,The rat activity gradually decreased,finally to rest, not death. Compared with group A, group E and H’s weight is obviously lightly, group F, G’weight is lightly,group B, C, D’weight is not change.2 m PAP, Right ventricular morphology changes of long-term hypoxia pulmonary hypertension rats: Blood vessel walls in lungs are thicken obviously, smooth muscle cells(SMC)of pulmonary small artery increased, the membrane(PAMT) thickening and luminal narrowing; and right ventricular hypertrophy, right ventricule hypertrophy became to develop significantly after eight weeks in group H; the change of pulmonary artery wall structure in group Fand G were between group E and H; group B、C and D had normal pulmonary artery wall structure. Compared with group A,group H’m PAP is increased most obviously,group F and G’s m PAP is increased obviously, between group E and H,and there’s no difference between group F and G. Group B, C, D’sm PAP is not changed.The chang of RVHI is the same as the m PAP.3 The expression of ET-1 In the lung tissue: Compared with group A, The expression level of ET-1 in grpup E and H is significantly increased, and in group H is increased even more higher, the level of ET-1 between group F and G is obviously incredsed, between group E and H, group F is increased more obviously than group G. and group B, C, D’s ET-1 is also increased,but the increasing level is less than their hypoxia control group, and the level of ET-1 is increased more obviously in group B than group C.4 The expression of ETAR In the lung tissue: Compared with group A, The expression level of ETAR in grpup E and H is significantly increased,and in group H is increased even more higher, the level of ETAR between group F and G is obviously increased,but there is no difference between them.and group B, C, D’s ETAR is also increased,but the increasing level is less than their hypoxia control group,and the level of ETAR between group B than group C is no difference.5 The expression of ETBR In the lung tissue: Compared with group A,The expression level of ETBR in grpup E and H is significantly decreased,and in group H is decreased even more higher, the level of ETBR between group F and G is obviously decreased,but there is no difference between them.and group B, C, D’s ETBR is also decreased,but the desreasing level is less than their hypoxia control group,and the level of ETBR between group B than group Cis no difference.Conclusions:1 In low oxygen conditions, the content of ET-1 and ETAR m RNA in rat lung tissue were significantly increased, but the content of ETBR were significantly deceeased.2 In low oxygen conditions, Within the lung tissue, increased expression of ETAR and ET-1, and the decreased expression of ETBR play an important role in the formation of hypoxic pulmonary hypertension.3 17-beta- estradiol and its metabolites 2-Methoxyestradiol can by reducing the ETAR m RNA content to downgrade the expression of ETAR, thus inhibiting ET-1 to promote proliferation of VSMCs function and vascular response to ET-1. it Can also be used by increasing the content of ETBR m RNA to raise ETBR expression, thus increasing ETBR to mediated the expansion of blood vessels effect, reduce pulmonary arterial hypertension.4 the ability of suppress the ET-1 release, 2-ME is significantly higher Than that of E2, but they have an similar impact on ETAR and ETBR.