Dependence of radioprotective activity of chitosan on its molecular mass

The influence of chitosan molecular mass (70, 10 and 5 kDa) on its radioprotective efficiency in mice experiments was studied. It was shown that chitosans with molecular masses of 70 and 10 kDa had similar radioprotective properties. The survival of mice increased up to 73% and 87% respectively at intravenous injection 15-30 min before a whole-body exposure to 137Cs gamma-radiation at a dose of 8 Gy (Cd97/30). Practically absolute loss of radioprotective activity occurred below a threshold of about 10 kDa. The results showed a high chitosan radioprotective activity in a wider range of molecular masses than it was supposed earlier.