Irreparable injury produced by irradiation of rat thymocytes in vitro.

Abstract

The extent to which rat thymocytes are capable of recovery from radiation injury as measured by several criteria was investigated. Incorporation of $\text{adenine-}8\text{-}{}^{14}{\rm C}$ into nucleic acids was depressed by 100 and 50 R, and there was no evidence of recovery of this process within 30 hours after irradiation. Fractionated irradiation with 2 hours between exposures did not reduce the damage to adenine incorporation produced by the same total dose given as a single exposure. Depression of adenine incorporation into nucleic acids and cell survival decreased exponentially as a function of radiation dose, which also suggests that the potential for recovery of radiation injury is absent in mature thymocytes.