Objective:To investigate the collagen changes of pulmonary arteriole and its significance in patients with rheumatic heart disease.Methods:The preoperative hemodynamic parameters were obtained by catheterization?The 79 cases of lung specimen for study group were taken from the right lower lobe after cardio-pulmonary bypass

and 10 cases for control group were from autopsy or biopsy.Immunohistochemical staining with antibodies against collagen type Ⅰ

type Ⅲ was performed by S-ABC method.The levels of collagen type Ⅰ and type Ⅲ were examined quantitatively under computerized image analysis system.The correlations were analyzed between the clinical data and collagen in pulmonary arteriole.Results:There were significantly higher levels of collagen type Ⅰ and type Ⅲ in pulmonary vessels of the study group than that of the control group.The worse the lesion was

the higher the levels of collagen type Ⅰ and type Ⅲ were for pulmonary vacular lesions of pathological grade 1 to 3

but for grade 4

the levels of collagen type I and type III were not higher than that of grade 3. The concentration of collagen type Ⅰ in arteriole wall was correlated with the factors such as the severity of pulmonary vascular lesions

mean pulmonary artery pressure

cardiac function and age. Conclusions:Proliferation of the collagen contributed to the formation and the maintenance of pulmonary hypertension and vascular lesions resulted from rheumatic heart disease. The content of collagen type Ⅰ and type Ⅲ in pulmonary vascular lesions of grade 4 resulted from rheumatic heart disease was not so much as that of grade 3.This was perhaps one of the reasons that why extreme pulmonary hypertension and severe pulmonary vascular disease were not contraindications for operation. If an operation is necessary

4 factors including pulmonary vascular lesion

pulmonary hypertension

age and heart function should be taken into consideration

because they had correlation with the content of collagen type I which was dominant in reversion of pulmonary vascular disease.