Background
Calcium and cholesterol play major roles in the formation of atherosclerosis. Whether severe atherosclerosis induced by co-administration of a mixture containing vitamin D2 (vit D2) and cholesterol can result in gastric hemorrhagic damage is unknown. Gastric oxidative stress and hemorrhagic ulceration in rats with atherosclerosis induced by co-administration of vit D2 and cholesterol and the protective effect of lysozyme chloride on this ulcer model were investigated.
Material and Method
Male Wistar rats were challenged intragastrically once daily for 9 days with 1.0 ml/kg of corn oil containing vit D2 and cholesterol to induce atherosclerosis. Control rats received the same volume of corn oil only. After 24-h fasting followed by gastric surgery, the rat stomachs were irrigated for 3 h with simulated rat gastric juice or normal saline. Various gastric mucosal ulcerogenic factors (acid back-diffusion, lipid peroxides, histamine concentration, and hemorrhagic ulcers) and defensive substances (mucosal glutathione and mucus secretion) were determined.
Results
Augmentation of serum calcium concentration, total cholesterol, and low-density lipoprotein was observed in atherosclerotic rats. Greater mucosal ulcerogenic parameters and lower defensive substances were achieved in these rats. High correlation between decreased mucosal glutathione and ulceration as well as between increased mucosal lipid peroxide levels and ulceration was also found in the atherosclerotic rats. Daily intragastric lysozyme chloride dose-dependently protected gastric mucosal hemorrhagic damage in the atherosclerotic rats.
Conclusions
Atherosclerosis induced by co-administration of vit D2 and cholesterol could produce gastric oxidative stress and hemorrhagic ulcer that was ameliorated by lysozyme chloride in rats.

Keywords: Peptic Ulcer Hemorrhage - prevention & control, Oxidative Stress - drug effects, Muramidase - therapeutic use, Glutathione - metabolism, Gastric Mucosa - pathology, Gastric Juice - metabolism, Ergocalciferols - administration & dosage, Corn Oil - administration & dosage, Cholesterol - administration & dosage, Atherosclerosis - metabolism