DISTRIBUTION OF EXTRACELLULAR-MATRIX PROTEINS IN INDOMETHACIN-INDUCEDLESIONS IN THE RAT STOMACH

Introduction: We investigated the distribution of extracellular matrix (ECM) proteins in indomethacin-induced lesions of the rat stomach. Me thod: Twenty rats received indomethacin orally at a dose of 8 mg/kg/bo dy weight. The animals were killed at 3, 6, 12, 24, and 48 h after adm inistration of the drug. The stomachs were removed and frozen in liqui d nitrogen. Cryostat serial sections of the lesions were immunostained with antibodies to collagen III, IV, and VI, laminin, and fibronectin . Results: Fibronectin was the dominant extracellular protein of the p rovisional ECM in deep gastric lesions and gastric ulcers. Collagen II I was strongly positive in stromal cells under the necrotic material i n gastric erosions. Basal membrane proteins (collagen IV and laminin) were found to originate from the muscularis mucosae at the ulcer edge. Conclusion: There is a typical distribution of ECM proteins in erosio ns and ulcers of the rat stomach. Fibronectin was most prominent in th e provisional matrix of gastric erosions and ulcers.