Local fibrinolytic activity and its structural basis in experimental gastric ulcers.

The stomach contains plasminogen activators localized to submucosal vessels and to the mucosa. To study the release of plasminogen activators from mucosal cells, we induced mucosal damage by pyloric ligature and instillation of 0.5 mol/l HCl in rats. After 4 h, all rats developed focal necrotic lesions and a diffuse mucosal damage, as studied both by light microscopy and by scanning electron microscopy. Diffuse mucosal damage was accompanied by significant increase (P less than 0.001) in mucosal fibrinolytic activity based on plasminogen activators. This activity was probably derived from injured mucosal cells since focal necrotic lesions (erosions and ulcers) with total denudation of the mucosal epithelium lacked fibrinolytic activity. The results obtained in this study support the hypothesis that plasminogen activators are released during cellular degeneration.