Gastric ulceration triggers local activation of IGF-1 in the ulcer margins. A: IGF-1 enzyme-linked immunosorbent assay of gastric tissue from sham-operated (S.O.) and gastric ulcers showing significant IGF-1 up-regulation at days 4, 6, and 12 after gastric ulcer (G.U.) induction. *P value <0.001, n = 4 to 5. B: Immunostaining with IGF-1-specific antibody. In normal gastric mucosa, IGF-1 expression is localized to cells of mucosal progenitor zone, PZ (b) (red staining). In ulcerated mucosa, IGF-1 expression is up-regulated in gastric ulcer margin healing zone, HZ, at day 6 (c and d) compared with normal gastric mucosa. d: Higher magnification of the same section showing IGF-1-positive cells are derived from gastric glands. e and f: Epithelial cells migrating onto and re-epithelizing granulation tissue of gastric ulcers at day 6 also exhibit strong staining for IGF-1 (arrow). a: Control staining performed in the absence of primary antibody did not show any positive staining. C: RT-PCR using Cox-2, Igf-1, and β-actin primers was performed using total RNA from gastric tissue of sham-operated control and gastric ulcer margins showing Igf-1 and Cox-2 mRNA up-regulation at days 4, 6, and 12. Semiquantification of RNA RT-PCR expressed as relative density to β-actin (bottom). Original magnifications: ×200 (Bd, Bf); ×100 (Be).