WR2721 BONE-MARROW RADIOPROTECTION - LIGHT AND ELECTRON-MICROSCOPE STUDY

To assess the radioprotection afforded by the S- 2- (3 aminopropylamin o) ethylphosphorotioic acid (WR2721), bone marrow obtained from mouse femora was examined by means of light and electron microscope 1, 3, 6 and 10 days after a single whole body X ray dose of 7 Gy. Comparing th e protected to the unprotected bone marrows, the following features we re observed in the protected ones: (1) less depletion of parenchyma ce lls; (2) less vascular dilatation and hyperemia in parenchyma; (3) app arently less apoptotic figures present 1 day after irradiation and (4) the recovery process occurred earlier. Despite the hyperemia in the p arenchyma during the injury phase, the continuity of the sinus wall wa s maintained in the protected and unprotected marrows. The morphometri c method used (NN/N ratio) allowed the estimation of the WR2721 bone m arrow radioprotection through the relation of vascular stroma and cell ular parenchyma.