Appearance of specific mucins recognized by monoclonal antibodies in rat gastric mucosa healing from HCl-induced gastric mucosal damage

Mucus is an important factor in the physiological defense mechanism of the gastrointestinal tract. We have reported that two distinct antigenicities reacting with anti-mucin monoclonal antibodies (mAbs), HCM31 and RGM26, emerged in epithelial cells regenerating from acetic acid-induced gastric damage in the rat. Here, we examined whether the expression of specific mucins occurred during the healing stage of acute gastric mucosal lesions, and what was the principal alteration of the mucus in the regenerating process of gastric epithelia from slight mucosal lesions. Eight-week-old male Wistar rats were used. The animals were administered 0.6 N hydrochloric acid, or 0.5% carboxymethyl cellulose sodium salt into their stomachs. Twenty-four, 48, and 72 h after the HCl administration, their stomachs were removed. Immunohistochemical observation was performed after staining with the mAbs, RGM21, RGM26, HIK1083, or HCM31. Twenty-four hours after the administration of HCl, mucous cells stained with RGM26 emerged in the deeper area of the surface epithelial cells in the damaged corpus mucosa. After 48 h, HCM31-positive cells were noted in the epithelial cells where the mucosal damage reached more deeply. The appearance of specific mucin species was observed in the regenerating epithelia of the rat during the healing process from acute gastric mucosal damage.