"EFFECT OF CIMETIDINE AND RANITIDINE ON LIPID PROFILE AND LIPID PEROXIDATION IN γ-IRRADIATED MICE"

Abstract

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.