ObjectiveTo evaluate the change of extracellular matrix (ECM) in diabetic rat lungs.MethodsUsing special staining,immunohistochemical method and imaging analysis,the changes of distribution,area,integral optial density and relative contents of lung ECM in diabetic rats were studied.ResultsThe distributions of elastic fibres,collagenic fibres and reticular fibres increased and roughened.The type Ⅳ collagen strong staining was localized in alveolar septum,the basement membranes of bronchiole and capillary,and distributed in cordal,plexiform.Laminin was strong stained and found in alveolar septum,epithelial cells of alveolar,and the basement membranes of bronchiole and pulmonary vessels in cordal and linear distribution.Image analysis showed the area,integral optical density and relative contents of elastic fibres,collagenic fibres,reticular fibres,type Ⅳ collagen and laminin were larger in diabetic rat lungs than in control groups.ConclusionThese results showed that the changes of ECM in early diabetic rat lungs were abnormal.