Digestion of proteoglycans in porcine pancreatic elastase-induced emphysema in rats.

Pulmonary emphysema was induced in rats by a single intratracheal instillation of pancreatic elastase. The short-term effects of elastase instillation on basement membrane components were evaluated using immunohistochemical and biochemical methods. Lung alveoli showed a decrease in heparan sulphate proteoglycan content (especially of its heparan sulphate chains) 3 h to 7 days after induction. Type IV collagen, laminin and fibronectin were not affected. The glycosaminoglycan content of the lung was decreased during the first 3 days after induction, while the glycosaminoglycan concentration in urine was increased during the first 4 days by an increase of heparan sulphate and dermatan sulphate. The increase in urinary glycosaminoglycan content was positively correlated with the extent of emphysema developed after 40 days. We conclude that proteoglycans are target molecules for elastase, and may be involved in the pathogenesis of emphysema.