Regeneration of gastric mucosa after aspirin-induced injury in the rat

Regeneration of gastric mucosa damaged by aspirin was studied in 6-week-old rats, using histologic and autoradiographic technics. Aspirin (120 mg/kg) was given by esophageal intubation either in a single dose or each day for 14 days. After a single dose, two types of lesion were observed in the mucosa of the body of the stomach: (a) superficial erosions which were already present after 30 minutes and which completely healed within 24 hours; (b) deeper erosions, reaching maximal numbers at 4 hours, which healed slowly with a median disappearance time of 5 days and which were associated with a focal increase in³H-thymidine-labeled cells. The peak increase in labeling occurred between 16 and 48 hours. The pattern and rate of healing was not altered by repeated daily aspirin. The investigation has demonstrated slow healing of deep mucosal erosions caused by aspirin; the slow healing can be explained by destruction of the progenitor zone by the initial injury.Supported by the National Health and Medical Research Council and the Alfred Hospital.Presented in part to the Australian Society for Medical Research, December 1971.