THE EFFECT OF~(60)Coγ RAY ON BRAIN PERMEABILITY TO METHOTREXATE IN MICE

This study was designed to evaluate the effects of irradiation on the peameability of mice brain to methotrexate (MTX). MTX was administered by intraperitoneal injection (10mg/kg) to unirradiated mice, and to mice receiving varying doses of cranial irradiation. 30 minutes after injection, MTX concentrations in brain and in blood were detected using phospho reseence method. There was a significant increase of MTX level in brain tissue after a single dose irradiatiOn (≥20Gy). Fractionated irradiation also increased MTX level in brain tissue. The effect of irradiation on brain drug permeability could be enhanced by hematoporphyrin derivative (HPD) given 30 minutes before irradiation.