Figure 4

Morphologic assessment and localization of ITF expression in rat gastric antrum at 12 days (A to C), 24 days (D), and 120 days (E to F) after acetic acid-induced ulceration. A, In situ hybridization using antisense ITF riboprobe, darkfield view, demonstrating ITF mRNA expression localized to the area of regenerative epithelium. Original magnification, ×50. B, ITF immunohistochemistry in tissue corresponding to A (original magnification, ×200), showing discrete ITF immunoreactivity (brown stain) in columnar cells lining cystically dilated glands and the elongated cleft epithelium adjacent to the ulcer scar and lining the luminal aspect of this epithelium (arrow heads). C, High-iron diamine histochemistry, showing atypical acid sulfomucin staining of regenerative mucosa (section corresponds to Fig. 3, D to F). Nuclear-fast red counterstain. D, In situ hybridization, ITF riboprobe, brightfield view, in regenerative gland 24 days after acetic acid injury, showing persistence of ITF mRNA up-regulation (arrowheads). L, lumen. E and F, Gastric atrophy and intestinal metaplasia in ulcer region, 120 days after acetic acid injury. In E, PAS/alcian blue histochemistry shows predominant alcianophilia marking an area of gastric atrophy (single arrow). Adjacent glands continue to resemble regenerative epithelium (double arrow). Original magnification, ×50. In F, dysplastic epithelium within the area of gastric atrophy displays persistent ITF expression (arrows).