Gastric antisecretory and antiulcer activity of bovine hemoglobin.

AIM To investigate gastric antisecretory and gastroprotective activity of bovine hemoglobin (B-Hb) in rats. METHODS Adult Albino-Wistar rats were divided into groups of 6 animals each. B-Hb in doses of 100, 300 and 900 mg/kg body weight was tested for gastric acid secretion and antiulcer activity. Gastric secretions were measured 6 h after pylorus ligation in rats pretreated with B-Hb. The acidity was measured by titrating gastric contents against 0.01 mol/L NaOH to pH 7. Indomethacin ulcers were produced by oral administration of 30 mg/kg bw in the rats pretreated with B-Hb one hour before indomethacin. Six hours after indomethacin stomach removed and ulcer index was recorded. Ethanol ulcer were produced by 1 mL of ethanol in the rats pretreated with B-Hb 30 min before the ethanol. One hour after ethanol stomach were cut open to score ulcers. Histological examination and analysis of gastric wall mucus, non-protein sulfhydryl groups (NP-SH), and myeloperoxidase (MPO) were carried in gastric tissue following ethanol administration. RESULTS In control rats pylorus ligation for 6 h resulted in the accumulation of 8.1 ± 0.61 mL of gastric secretion. The treatment of the rats with 100, 300 and 900 mg/kg of B-Hb produced a significant decrease in the volume of gastric secretion 5.6 ± 0.63, 5.5 ± 0.75 and 4.7 ± 0.58 mL respectively as compared to the control group [analysis of variance (ANOVA) F = 4.77, P < 0.05]. The lesion area in the control group was found to be 22.4 ± 3.2 mm(2) six hours after the administration of indomethacin. Treatment of rats with B-Hb at doses of 100 mg/kg (24.3 ± 3.29 mm(2)), 300 mg/kg (16.2 ± 1.45 mm(2)) and 900 mg/kg (12.6 ± 1.85 mm(2)) produced a dose dependent decreased the lesion scores (ANOVA F = 4.50, P < 0.05). The ulcer index following one hour after 1 mL ethanol was 7.1 ± 0.31. Pretreatment of rats with B-Hb at the doses of 100 mg/kg (2.5 ± 0.42), 300 mg/kg (2.1 ± 0.4) and 900 mg/kg (0.7 ± 0.21) significantly inhibited the formation of gastric lesions (ANOVA F = 63.26, P < 0.0001). Histological examination of gastric mucosa following ethanol showed significant lesions in the form of gastric pits with detachment of the surface epithelium; vacuolation of epithelial cells and elongation of microvessels. The changes were dose-dependently attenuated by B-Hb. The treatment of rats with ethanol significantly decreased the Alcian blue binding capacity of gastric wall mucus (480 ± 25.6 μg Alcian blue/g of tissue) as compared to control rats (667 ± 25.8 μg). Pretreatment of rats with B-Hb at the doses of 100 mg/kg (516 ± 31.6 μg/g), 300 mg/kg (558 ± 28.8 μg/g) and 900 mg/kg (654 ± 33.8 μg/g) significantly attenuated ethanol induced depletion of gastric wall mucus (ANOVA F = 8.05, P < 0.005). A significant and dose dependent increase of gastric mucosal NP-SH (ANOVA F = 19.62, P < 0.001) and decrease in MPO activity (ANOVA F = 3.1, P < 0.05) was observed in B-Hb treated rats. CONCLUSION B-Hb possesses significant gastric antisecretory and gastroprotective activity against experimentally induced gastric lesion. The gastroprotective effects of B-Hb are accompanied by inhibition of neutrophils activity, reduction of oxidative stress and maintenance of mucosal integrity.