Radioprotective effects of 2-iminothiazolidine derivatives against lethal doses of gamma radiation in mice.

Although thiol-containing compounds have long been known to possess radioprotective properties, their therapeutics utility is limited by their side effects at radioprotective doses. In this study, a series of 2-iminothiazolidine derivatives were prepared and their toxicity and radioprotective effects in NMRI mice were determined using the LD50/30 end point. The LD50 values, as determined by a Probit analysis, were between 11 and 14 mg/kg. For studying radioprotective effects, one-sixth of the toxic LD50 values were used, namely 2 and 2.2 mg/kg. To evaluate the radioprotective capabilities, mice were exposed to lethal doses of cobalt-60 gamma-radiation alone or in the presence of compounds. The percentage survival of mice at 30 days for these compounds compared to control mice were 10 to 30% when injected 15 and 30 minutes before gamma-irradiation. They were significant compared to the control group (P < 0.05). 2-Imino-3-(benzoylmethyl)thiazolidine derivatives showed different radioprotective effects when injected at different times before irradiation, but were not statistically significant from each other (P > 0.05).