Role of matrix metalloproteinases in pulmonary vascular remodeling in rats with pulmonary hypertension induced by chronic hypoxia hypercapnia

Objective:To investigate the role of matrix metalloproteinases in pulmonary vascular remodeling in rats with chronic hypoxia and hypercapnia induced pulmonary hypertension.Methods:Twenty male Sprague Dawley rats were randomly divided into two groups:normal control group(C),hypoxia hypercapnia group(H). Content of matrix metalloproteinases was measured with enzyme combinate immune cross methods.Results:①The mean pulmonary artery pressure(mPAP) and weight ratio of right ventricle to left ventricle and septum(RV/LV+S) of H group were higher than C group(P0.01).②Content of hydroxyproline in H group was significantly higher than that in C group(P0.01).③Light microscopy showed that vessel wall area/total area(WA/TA),vessel cavity area/total area(EA/TA) and media thickness of pulmonary arterioles were much higher in rats of H group than those in C group(P0.01).④The observation under electron microscopy showed proliferation of smooth muscle cells in media and deposition of collagen in pulmpnary arterioles in rats of H group,but no same performance was found in C group.⑤Pulmonary tissue homogenates MMP 2 and MMP 9 levels of H group were significantly increased(P0.01),compared with control group.Conclusion:Expression of matrix metalloproteinases in pulmonary tissues was enhanced by hypoxia hypercapnia,which could be involved in pulmonary vascular remodeling in the rats with pulmonary hypertension.