Mikio Ito, Ayako Ban and Masashi Ishihara
Department of Pharmacology, Faculty of Pharmacy, Meijo Unuversity, 150
Yagotoyama, Tenpaku-ku, Nagoya 468-4503, Japan
Abstract: In this study, we compared the effects of low molecular
weight (LMW) chitosan (MW: 25,000-50,000), high molecular weight (HMW) chitosan
(MW: 500,000-1000,000) and chitin on ethanol-induced gastric mucosal injury
and on the healing of acetic acid-induced gastric ulcers in rats. Oral administration
of LMW chitosan (250, 500 and 1000ﾊmg/kg) dose-dependently prevented ethanol-induced
gastric mucosal injury. Repeated oral administration of LMW chitosan (100,
200 and 400ﾊmg/kg twice daily) also dose-dependently accelerated the gastric
ulcer healing. However, the effects of HMW chitosan and chitin on the gastric
mucosal injury formation and the gastric ulcer healing were less potent
than those of LMW chitosan. LMW chitosan (250 and 500ﾊmg/kg, orally) was
ineffective in inhibiting gastric acid secretion in pylorus-ligated rats,
although it had a weak acid-neutralizing action. LMW-chitosan (250, 500
and 1000ﾊmg/kg orally) dose-dependently prevented the decrease in gastric
mucus content induced by ethanol. These results indicate that of the three
compounds, LMW chitosan has the most potent gastric cytoprotective and ulcer
healing-promoting actions. In addition, gastric mucus-increasing action
of LMW-chitosan may be, at least in part, related to the anti-ulcer effect
of this compound.
Keywords: Chitin, Chitosan, Anti-ulcer action, Gastric cytoprotection