"effect of cimetidine and ranitidine on lipid profile and lipid peroxidation in γ-irradiated mice"

elevated amounts of free radicals due to ionizing radiation have damaging effects on the body. h2-receptor antagonists have potential oxygen radical scavenging properties. we tried to determine the effects of two h2-receptor antagonists (cimetidine and ranitidine) on lipid peroxidation (lpo) and lipid profile (lp) in plasma and liver of γ-irradiated (1gy/day for 3 days) balb/c mice. the control group of mice were fed with normal food and drinks but the experiment group of mice were fed control diet and drinking water, containing cimetidine or ranitidine (1mg/lit). after 3 days of supplementation, the animals were subjected to sublethal γ-radiation, which caused a significant increase in cholesterol level in experimental group (100% increase in comparison with the control group), but the amount of phospholipids did not change. the ratio of cholesterol to phospholipid showed a slight increase. also γ-irradiation caused a significant increase in lipid fluorescence (11-48%), conjugated dienes (33-81%) in liver and increase in malondialdehyde (19-300%) in serum of mice who had received 1.09-3.1 gy for 1-3 days. cimetidine or ranitidine supplementation was able to restore the changes of lpo and lp in mice (1 gy-radiated for 3 days). it is therefore concluded that the mice treated with cimetidine or ranitidine were able to tolerate biomembrane damages provoked by sublethal γ-radiation. this supports the hypothesis that cimetidine or ranitidine may afford an efficient protection against ionizing radiation or diseases that are characterized by in vivo free radical-mediated oxidative stress mechanisms.