Changes of extracellular matrix in type II cells and thickness of basement membrane in old rats

Objective: To observe the changes of extracellular matrix in type Ⅱ cells and thickness of basement membrane beneath type Ⅱ cells in old rats. Methods: Inmmunocytochemistry and image analysis were used to measure the relative contents of laminin and fibronectin in type Ⅱ cells in young (1 2 months), adult (8 9 months) and old (25 28 months) rats. Results: There were less laminin, more fibronectin in type Ⅱ cells and thicker basement membrane beneath type Ⅱ cells in old rats. Conclusion: These results suggest the altered metabolism of extracellular matrix from type Ⅱ cells in old rats, which may result in abnormal recovery of alveoli after being injured.