Expression of MMP-2 mRNA and MMP-9 mRNA in pulmonary arterioles ofrats with pulmonary hypertension induced by chronic hypoxia hypercapnia

AIM:To investigate the expression of matrix metalloproteinases(MMPs) in pulmonary arterioles of rats with chronic hypoxia and hypercapnia-induced pulmonary hypertension.METHODS:MMP-2, MMP-9 and MMP-2 mRNA, MMP-9 mRNA were observed in pulmonary arterioles by the techniques of immunohistochemistry and in situ hybridization.RESULTS:①The mean pulmonary artery pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV+S) of hypoxia-hypercapnia groups were higher than those of normal control group (P＜0.01). ②Light microscopy showed that vessel wall and media of pulmonary arterioles were thicker in rats of hypoxia-hypercapnia groups than normal control group. There were vessel smooth muscle cell hypertrophy, vessel cavity straitness in hypoxia-hypercapnia group, but no same performance was found in normal control group. ③The expression of MMP-2, MMP-9 and MMP-2 mRNA, MMP-9 mRNA in pulmonary arterioles were significantly higher in rats of hypoxia-hypercapnia groups than control group (P＜0.01).CONCLUSION:Expression of matrix metalloproteinases in pulmonary arterioles is enhanced by hypoxia hypercapnia. This may be involved in pulmonary vascular remodeling in rats with pulmonary hypertension.