Protective properties of colloidal bismuth subcitrate on gastric mucosa

Colloidal bismuth subcitrate (CBS), PGE2, sucralfate, and cimetidine have been investigated for their mucosal protective effects in the ethanol-induced gastric erosion model in rats; moreover, to gain an insight into the mechanisms of action of CBS, its ability to stimulate the synthesis of gastric mucosal PGE2 was determined. Although less potent than PGE2 at inhibiting ethanol-induced gastric lesions, CBS was about 4 times more potent than sucralfate. Cimetidine displayed only very weak protective activities. CBS showed a time-dependent inhibition of ethanol-induced lesions. Complete protection was observed 15 min after treatment with CBS and partial protection was observed at 8 h, although no protection was found at 16 h. CBS increased the potential of rat gastric mucosa to synthesize PGE2 in a dose-dependent way. Up to 3-fold increases above the basal levels were found. Peak synthesis of PGE2 occurred 15 min after CBS and elevated levels were still found after 4 h. It is concluded from these studies that CBS produces potent gastric protection towards ethanol-induced injury in the rat. CBS also considerably increases the ability of rat gastric mucosa to synthesize PGE2 which may be an underlying biochemical mechanism for its protective properties on the gastric mucosa.