OBJECTIVETo study the effect and mechanism of chimonin on pulmonary arterioles I and III type collagen metabolism in pulmonary hypertension rats induced by chronic hypoxic hypercapnia.

METHODSThirty-six Sprague-Dawley rats were randomly divided into three groups: normal control group(A), hypoxic hypercapnic group(B), hypoxic hypercapnia + chimonin group(C). Collagen I, III and their mRNA, Blood CO concentration (COHb%), activity of HO-1 in blood serum and lung homogenate, content of hydroxyproline in lung homogenate, pulmonary arteriole micromorphometric index were observed.

RESULTSHypoxic hypercapnic rats's mPAP, Hyr of lung homogenate, content of I type collagen and I type collagen mRNA in pulmonary arterioles, were significantly higher than those in control group, pulmonary vessel remodeling of hypoxic hypercapnic rats was significant, those changes in hypercapnia + chimonin group were significantly lower than those in hypoxic hypercapnic group. Blood CO concentration, activity of HO-1 in blood serum and lung homogenate in rats of hypoxic hypercapnic rats were significantly higher than those of control group, and those of hypercapnia + chimonin group were even higher than hypoxic hypercapnic group (P < 0.01). There was no significant difference in mCAP, content of III type collagen and their mRNA in three groups (P > 0.05).

CONCLUSIONChimonin can reduce pulmonary hypertension and pulmonary vessel remodeling induced by hypoxic hypercapnia through inhibiting proliferation of collagen I, the mechanism maybe is up regulating endogenous carbon monoxide system.