INFLUENCE OF OXYGEN THERAPY ON PLASMA AND LUNG TISSUE HOMOGENATU U-II LEVELIN RATS WITH HYPOXIA-INDUCED PULMONARY HYPERTENSION

Objective: To investigate the alteration of plasma and lung tissue homogenate Urotensin Ⅱ(U-Ⅱ) levels in rats with hypoxia-induced pulmonary hypertension and to study the role of oxygen therapy in the development of HPH.Methods: Thirty male wistar rats were randomly divided into three groups: control group,group with hypoxia for 14 days and group with oxygen therapy after hypoxia for 7 days,ten rats per group.Mean pulmonary artery pressure(mPAP),mean Systematic artery pressure(mSAP) and the ratio of the weight of right ventricle to that of left ventricle plus septumwere measured.The plasma and lung tissue homogenate levels of U-Ⅱ were measured.The structure in pulmonary arteries were examined using optical microscope.Results:Compared with the control group,mPAP,RV/(LV+S),the plasma and the lung tissues homogenate levels of U-Ⅱ in hypoxia group were significantly higher respectively(P0.05).The smooth muscle cells(SMC)proliferation,the collagen deposition in the vassels wall and every calibre showed marked thickening were observed by optical microscope.Compared with hypoxia group,mPAP,the plasma and the lung tissues homoganate levels of U-Ⅱ oxygen therapy group were significantly lower respectively(P0.05) while there were no significant differences about RV/(LV+S) between the two groups.The thickened caliber was relieved significantly by optical microscope.Conclusion:The chang of U-Ⅱ may be involved in the development of HPH.The plasma and the lung tissues homogenate levels of U-Ⅱ were significantly lower and pulmonary vascular remodeling were relieved by oxygen therapy.