Mice's brain radioprotection: comparative efficacy of a series of aminothiols and aminothiol precursors

Abstract

A serie of radioprotective aminothiols was checked upon irradiation of the mice's brain. Cysteamine protects efficiently the brain as soon as 15 minutes after its administration. Among the tested aminothiols, it was the most effective compound. 2-isopropyl 1,3-thiazolane, rapidly hydrolysed, delivers a large amount of cysteamine in the brain and was nearly as potent as exogenous cysteamine. The other thiazolanes which delivered only progressively cysteamine or 2-mercaptopropylamine during a long period of time showed lesser efficacy. WR 2721 which did not penetrate the brain exhibited only a feeble radioprotection. The imperviousness to straight active aminothiols may be compensated by the diffusion of their precursors across the blood brain barrier and by their speed of hydrolysis, yielding active aminothiols during a short period of time between their administration and the irradiation.