Comparison between the effects of crude saikosaponin and 16, 16-dimethyl prostaglandin E2 on tannic acid-induced gastric mucosal damage in rats.

Hung, C.R., T.S. Wu and T.Y. Chang. The comparison between the effects of ethanol-extracted saikosaponin (SS) and 16, 16-dimethyl prostaglandin E2 (dmPGE2) on gastric acid back diffusion and mucosal damage induced by 100 mg/kg of acidified tannic acid (tannic acid dissolved in 100 mm HCl + 54 mM NaCl solution) was studied in the vagotomized rat. Crude saikosaponin (500 mg/kg) given by intragastric irrigation (I.G.) produced a significant inhibition (p < 0.05), while dmPGE2 (100 micrograms/kg) provoked a significant increase (p < 0.05) in acid back diffusion induced by acid solution. When graded doses of SS (100-1000 mg/kg) were added to acidified tannic acid solution and instilled to the stomach, a dose-dependent inhibition in acidified tannic acid-induced mucosal ulceration and acid back diffusion was achieved. The decrease in the H+ concentration and the increase in the Na+ concentration in the final samples induced by acidified tannic acid were also significantly (p < 0.05) inhibited by the same doses of SS. However, neither intraduodenal (I.D.) nor intravenous (i.v.) administration of SS was effective in inhibiting these ulcerogenic parameters. When dmPGE2 (3-100 micrograms/kg) was given concomitantly with acidified tannic acid solution, the acid back diffusion as well as mucosal ulceration provoked by acidified tannic acid were not significantly improved. The volume of luminal contents but not electrolyte concentrations in the final sample was considerably increased by adding dmPGE2 to the acidified tannic acid solution. The failure of I.D. or i.v. of dmPGE2 in inhibiting tannic acid-induced acid back diffusion and mucosal ulceration was also observed in other series of experiments.(ABSTRACT TRUNCATED AT 250 WORDS)