Radioprotection by Thiazolidines at the Cellular Level

Radioprotection by a number of thiazolidine derivatives was studied in vitro. Reproductive integrity of single cells was used as a parameter for survival after irradiation. Thiazolidine itself did not protect when dissolved in culture medium, but a good protective activity was found when it was dissolved in rat blood. Rat blood improved also the radioprotective activity of most other thiazolidine derivatives. The best protection was obtained with thiazolidines in which the carbon at the 2 position was substituted by germanium. No correlation was evident between the degree of protection and release of a free SH group by hydrolysis of the thiazolidine ring. The results support a previous suggestion by Terol, Fernandez, Robbe, Châpat, Granger and Sentenac-Rovmanov (1978) that the thiazolidines proper and not their hydrolysis products are responsible for radioprotection.