Alteration of mucins in rat gastric mucosa healing from acetic acid-induced ulcer: An immunohistochemical study using monoclonal antibodies against gastric mucins

We examined the alteration of mucins in the rat gastric mucosa injured with acetic acid by means of an immunohistochemical method using three distinct monoclonal antibodies (MAbs) against the gastric mucins: RGM21, RGM26 and HIK1083, each reacting with the mucin molecule located in the specific region and layer of the rat gastric mucosa. An acetic acid induced-ulcer was prepared in eight-week-old male Wistar rats and the animals were killed at 10, 20 and 30 days after the acid insult. Even at 10 days, mucous cells positive to RGM26, which can only recognize the surface mucous cells of antral region in the normal mucosa, emerged at the regenerating epithelia. At 20-30 days, not only the distal side, but also the proximal side of these epithelia were occupied with the cells strongly stained with this MAb. The reaction with RGM21, which recognizes the surface epithelial cells of normal corpus mucosa, reduced in the regenerating epithelia. HIK1083 staining indicating the gland mucous cells increased around the ulcer area at earlier stage of healing, and the staining area was expanded to the bottom of the regenerating mucosae at 20-30 days. These results indicate a distinguished expression of the antral-type mucins in the regenerating epithelia during the healing process of the acetic acid-induced gastric ulcer.