Evidence concerning the pathogenesis of gastric haemorrhagic
ulcer produced by betel quid chewing (BQC) is lacking. This research first proposes that alterations of mast cell histamine release and gastric acid back-diffusion are important in modulating gastric microvascular permeability and mucosal haemorrhagic
ulcer in BQC-fed rats. The effects of several
histamine receptor antagonists on this
ulcer model also were evaluated. Male Wistar rats were fed with BQC diet or normal pellet diet. After 1, 30 and 90 day(s), rat stomachs were irrigated for 3 h with either
normal saline or simulated gastric juice. Gastric acid back-diffusion, mucosal
histamine concentration, microvascular permeability, as well as
luminal haemoglobin content and
ulcer areas were determined. Severe gastric haemorrhage and mucosal ulcerations, particularly in acidic stomachs, were observed in BQC-fed rats. A high correlation was observed between
histamine and gastric haemorrhage, as well as between
acid back-diffusion and mucosal ulceration was found in rats fed with BQC. This haemorrhagic
ulcer in BQC-fed rats was effectively ameliorated by intragastric
ketotifen,
ranitidine or their combination. In conclusion, enhancement of
acid back-diffusion, mast cell histamine release and microvascular permeability is important in modulating gastric haemorrhage and
ulcer in BQC-fed rats.