Study of radioprotective properties of chitosan at gamma-irradiation

The objective of this study was the analysis of adaptogenic effects of chitosan at gamma-irradiation. The study of radioprotective properties of chitosan was carried out on male mice having the weight of 20-25 g, exposed to gamma-irradiation at the doses of up to 800 bar at the Gamma Panorama unit (radiation source – Cs137, gamma dose rate – 14 R/min, duration of irradiation – 58.5 min). 4 experimental and 2 control groups with 7 animals in each have been formed. The medicine dose schedule, allowing to identify both the prophylactic effect and the therapeutic effect of chitosan, was used in the experiment. It was found out in experiments on white mice, with the purpose of determining 50% lethal dose (LD50) that chitosan belongs to the substances of hazard class 4 because its LD50 considerably exceeds 5000 mg/kg; at this, the toxicity of chitosan decreases parallel to its molecular weight decrease. The prophylactic and therapeutic effect of low-molecular chitosan (molecular weight 5-10 kDa) as abdominal injection at the doses of 200 mg/kg of body weight. It has been demonstrated that the mice from the experimental group I that received chitosan 3 days before the irradiation remained alive throughout the entire observation period (30 days).  In the animals of II, III, IV experimental groups that received chitosan in 3, 9 and 22 days after the irradiation, the survival rate by the experiment end was 86, 43 and 29%, respectively, with the 100% death of animals in the control group I (irradiated animals without the use of chitosan) and full safety of animals in the control group II (non-irradiated animals).