Mechanisms of action of leptin in preventing gastric ulcer

Figure 1 Photomicrograph of macroscopic appearance of the glandular mucosa, showing the effect of AE (A) and Indo (C) in the absence (A and C) and presence of 10 μg/kg dose of leptin (B and D). These photographs are typical of six such tissues.

Figure 2 A: The ulcer indices of saline and different concentrations of leptin (1-50 μg/kg) against Indo. Each value is a mean±SE. Asterisks indicate significant difference when compared to saline control (^aP < 0.05, ^bP < 0.01); B: The degree of prevention of Indo-induced ulcerations after treatment with different doses of lansoprazole and omeprazole (each used at 1-10 mg/kg), leptin (10 μg/kg) and ranitidine (50 mg/kg). Each value is a mean±SE. Asterisks indicate significant difference (^dP < 0.001) when compared to saline control.

Figure 3 The effect of increasing doses of leptin (1-10 μg/kg), lansoprazole (1-10 mg/kg), and omeprazole (0. 5-10 mg/kg) on AE-induced ulceration in rats. Each value is a mean±SE. Asterisks indicate significant difference, ^aP < 0.05, ^bP < 0.001 vs controls.

Figure 4 The ulcer prevention ability of leptin (10 μg/kg), when Indo was used to induce ulcer in L-NAME-pretreated animals. Each value is a mean±SE. Asterisks indicate significant difference, ^bP < 0.001 vs controls.

Figure 5 The ulcer prevention ability of leptin (10 μg/kg), in AE-induced ulcer after Indo or L-NAME pretreatment. Each value is a mean±SE. Asterisks indicate significant difference, ^bP < 0.001 vs controls. ^dP < 0.001 shows the significant difference in the effect of leptin on saline-treated and L-NAME-pretreated rats.

Figure 6 The effect of increasing doses of leptin (1-10 μg/kg) on AE-induced ulcer and prostaglandin E₂ levels in the gastric glandular mucosa in rats. Each value is a mean±SE. ^bP < 0.01, ^dP < 0.001 indicate significant difference in percentage ulcer index compared to AE-treated rats taken as 100%. ^fP < 0.01 shows the significant difference in the level of prostaglandin E₂ compared to AE-treated rats taken as 100%.

Figure 7 Gastric mucosal layer of rats stained with PAS showing (A) normal epithelium from control rats; (B) damaged epithelium (●) and (C) repaired epithelium after leptin treatment. Lower panel shows the AB (pH 1.0) staining showing mucus in (D) normal epithelium; (E) loss of epithelial mucus due to AE (★) and (F) presence of epithelial mucus after leptin treatment (bar = 6 μm; magnification 40×).