Time course of mucosal cell proliferation following acute aspirin injury in rat stomach.

The time course of replicating cell proliferation in the gastric fundic mucosa following acute aspirin-induced injury was determined by BrdU labeling. Gastric erosions were produced in adult rats by gastric gavage using aspirin (200 mg/kg) suspended in 0.15 M HCl. Lesion scores indicated significant gross injury in the aspirin-treated rats at all times measured (from 2 to 48 hr). BrdU labeling was not elevated at 2 or 8 hr after gavage. A significant increase in labeling was observed at 15 hr, reached a maximum at 16 hr, and declined with a slight, but significant increase still present at 48 hr. Elevations in BrdU labeling were uniform and seen in areas adjacent to and distant from the gross injury. The BrdU labeling in the fasted control rats decreased during this same time period. The height of the proliferative zone was not altered from control in the aspirin-treated rats despite the marked differences in proliferation activity. This study demonstrates the importance of the time course in the assessment of mucosal cell proliferation following injury.