Healing process of experimental esophageal ulcers induced by acetic acid in rats.

We studied the healing of acetic acid-induced esophageal ulcers in rats with respect to the cellular kinetics. Esophageal ulcers were induced by topical application of acetic acid to the serosal surface. Well-demarcated circular or elliptical ulcers had developed by day 3 after the acid treatment. These ulcers began to decrease in size from day 7 and had healed by day 14. Histological and cellular kinetic findings, with bromodeoxyuridine (BrdU), were degeneration of the esophageal mucosa on day 1 and ulcer formation on day 3, with an increase in the number of BrdU-labeled cells in the esophageal mucosa around the ulcer. On day 7, regenerated epithelium was found to extend towards the ulcer base and the regenerated epithelium had become thicker, with papilla formation, by day 10. On day 14, the ulcer base was covered with thickened regenerated mucosa, with a decrease in the number of BrdU-labeled cells. Marked proliferative activity of the regenerated mucosa and thickening of the esophageal mucosa, with papilla formation, were observed during the healing process.