Radioprotection of rat subependymal plate with 4-OH sodium butyrate.

The central nervous system is a radiation-dose-limiting structure, and cellularity of the rat subependymal plate (a location of neuroglial stem cells) has been used as a model of radiation damage. In the present work, an attempt has been made to improve its radiation tolerance using 4-OH sodium butyrate (gamma OH). Adult rats received 10-Gy 250-kV (peak) x-rays or 3.5-Gy 15-MeV deuterons plus Be neutrons. Cell counts were obtained by histological examination of the subependymal plate. Photon and neutron irradiation alone resulted in a mean cell depletion of 62% and 58%, respectively, compared with sham-irradiated controls, which was not statistically significant; the relative biologic effectiveness was 2.9. In the absence of radiation, gamma OH did not significantly alter the cellularity of the subependymal plate, compared with that in controls treated with chloral hydrate. At doses greater than or equal to 1 g/kg, gamma OH was associated with a statistically significant reduction of subependymal plate cell depletion in animals treated with photon or neutron radiation, and the magnitude of the effect was similar. Arterial blood gas analysis failed to show a significant difference in arterial oxygen tension between control and test animals.