Radiomodifying effects of calcium salts on laboratory mice

Study of substances that could protect against radiation effects, lethality and genotoxicity, started in the beginning of the nuclear era. At the present time research and development of new more effective compounds, reducing radiation effects on humans and biota, is continuing. Known radioprotective agents can be divided into radioprotectors including radiomitigators, adaptogens and adsorbents. Adaptogens enhance resistance of a body to radiation, they activate antioxidant, reparation and other protective systems. The most part of adaptogens have low toxicity, due to their properties to activate regulatory systems the adaptogens also activate the protective response to radiation. It is known that calcium-containing salts protect a body during external acute or chronic exposure to radiation, and internal exposure to incorporated radioactive substances. The authors wrote that exposure to radiation causes reduction of calcium level in the blood and together with that calcium level in tissues enhanced sharply (by 15 times). This can be due to disturbance of calcium metabolism in a body. The paper aims to study if calcium salts of carbonic and gluconic acids activate radioresistance of mice exposed to gamma-radiation. The diet of white outbred mice (females) was fortified with calcium salts (0.1 g/animal), or calcium salts and vitamins A and D2. The mice consumed the food fortified with calcium salt 3-7 days before exposure to radiation (dose - 8 Gy, dose rate - 2 Gy/min) and 6-10 days after exposure. 30-Day survival of animals fed food fortified with calcium salt enhanced by 80%, whilst the survival of mice in the control group consumed food free of calcium salts after exposure to 8 Gy was 31.7%. Adding 10IU of vitamin A and 1IU of vitamin D2 to food allowed increasing the survival by 10.5 and 15.0% more, and total survival was 90.5 and 95.0%. It is interesting, that survival of mice begun the consumption of food fortified with calcium carbonate in 4 days after irradiation was 80% higher than in miceconsumed food without additives. All indications are that calcium salt added to mice diet acts as adoptogen and has beneficial effect on survival of irradiated animals.