Changes in Serum and Cell Homeostasis under Irradiation: Factors of Distant Action

Abstract

Extracellular DNA-containing substances can be used as a marker of the balance between two processes: elimination of cells with critical number of lesions and repair of genetic material due to the work of adaptive systems. The idea of using this criterion was inspired by the results of measuring exDNA in blood plasma of chronically irradiated individuals. Here we used material obtained after gamma-irradiation (total dose 0.5 Gy) and subsequent culturing of PHA-stimulated human peripheral blood lymphocytes. The culture medium and exDNA isolated by various methods were treated with DNase and pronase. The concentration of free exDNA isolated by phenol extraction was an individual sign. The culture medium supernatant contained considerable amounts of exDNA in the form of nucleoprotein; cleavage of the protein component of this nucleoprotein considerably increased the size of fragments (from 1 to 20 kb) and reduced their resistance to DNase.