AIM: To study the effect of chronic hypoxia on L-Arginine/NO pathway in rat pulmonary artery. METHODS: Changes in pulmonary artery L-Arginine(L-Arg) transport, nitric oxide synthase (NOS) activity, plasma nitrite level and L-Arg level in HPH rats were investigated. RESULTS: (1) The mean pulmonary arterial pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV+S) of HPH group were higher than those in control group (P

AIM:To investigate the effect of puerarin on pulmonary vessel collagen metabolism in pulmonary hypertension rats induced by chronic hypoxia and hypercapnia. METHODS: Collagen Ⅰ,Ⅲ and their mRNA were observed in pulmonary arterioles by the technique of immunohistochemistry and in situ hybridization. RESULTS: ① Light microscopy showed media thickness of pulmonary arterioles was much higher in HH(hypoxic-hypercapnia) group than that of NC(normal control) group, and, vessel cavity turned more straiter in HH group than that of NC group.However, the damage of pulmonary arterioles in HP(hypoxic-pueratin) group was much slighter than that of HH group. ② The levels of plasma ET-1 and lung homogenates Hyr were much higher in HH group than those of NC group( P 0.05). CONCLUSION: Puerarin inhibited the deposition of collagen and improved pulmonary vessel remodeling.

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