ABSTRACT
The influence of different cells on death and pycnosis of thymocyte nuclei after in vitro irradiation has been investigated. It has been shown that the removal from the thymocyte suspension of cells, having the activity of natural killers, medullar thymocytes, and macrophages, does not influence the radiation-induced damage to cortical thymocytes. The injury of exposed thymocytes decreases, however, after incubation them with nonirradiated thymocytes or cultured cells, the efficiency of the latter being dependent on the type of cells. The data obtained may indicate that the exposed thymocytes interact with each other and exchange some factors that promote their injury.
Subject(s)
Cell Communication/radiation effects , Interphase/radiation effects , Thymus Gland/radiation effects , Animals , Cell Death/radiation effects , Cells, Cultured/cytology , Cells, Cultured/radiation effects , Killer Cells, Natural/cytology , Macrophages/cytology , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Rats , Rats, Inbred Strains , Thymus Gland/cytologyABSTRACT
A study was made of the influence of cytosol and conditioned medium, obtained at different times of incubation of irradiated thymocytes, on native thymocytes, as well as of the influence of mixing the suspension and changing the medium and the enzyme inhibitors, involved in metabolism of arachidonic acid, on the radiation injury to thymocytes. Cytosol of thymocytes, incubated for 60 min after irradiation, was shown to exert an insignificant toxic effect on native thymocytes. The conditioned medium of irradiated thymocytes is virtually ineffective. The mixing of the suspension upon incubation and the changing of the medium reduced the damage to exposed thymocytes while inhibitors of phospholipase A2 and lipoxygenase prevented completely the radiation-induced pyknosis of nuclei, whereas a inhibitor of cyclooxygenase did not influence it. It is inferred from the data obtained that unstable lipoxygenase products may serve as mediators of intercellular interactions of exposed thymocytes.
Subject(s)
Cell Communication/radiation effects , Interphase/radiation effects , Thymus Gland/radiation effects , Acetophenones/pharmacology , Animals , Arachidonic Acid/antagonists & inhibitors , Cell Communication/drug effects , Cell Death/drug effects , Cell Death/radiation effects , Cell Nucleus/drug effects , Cell Nucleus/radiation effects , Cells, Cultured/drug effects , Cells, Cultured/radiation effects , Culture Media , Cytosol/drug effects , Cytosol/radiation effects , Indomethacin/pharmacology , Interphase/drug effects , Lipoxygenase Inhibitors/pharmacology , Male , Masoprocol/pharmacology , Phospholipases A/antagonists & inhibitors , Phospholipases A2 , Rats , Rats, Inbred Strains , Thymus Gland/cytology , Thymus Gland/drug effectsABSTRACT
In experiments with irradiated cells of Chinese hamster and Ehrlich ascites tumor a study was made of the influence of energy provision on their interphase death rate. The presence of the uncoupler of respiration and oxidative phosphorylation--carbonyl cyanide-3-chlorophenylhydrazone--in a medium without glucose was shown to drastically increase the interphase death rate of cells of both types, whereas this effect was not observed in a medium with glucose.
Subject(s)
Cell Survival/radiation effects , Energy Metabolism/radiation effects , Interphase/radiation effects , Animals , Carbonyl Cyanide m-Chlorophenyl Hydrazone/pharmacology , Cell Line , Cell Survival/drug effects , Dose-Response Relationship, Radiation , Energy Metabolism/drug effects , In Vitro Techniques , Interphase/drug effectsABSTRACT
Interphase death of in vitro irradiated (200 Gy) Ehrlich ascites tumor cells was studied as a function of oxygenation level and medium pH. The presence of oxygen both during and after irradiation as well as the increase in pH from 7.4 to 8.1 were shown to increase interphase death rate. The pronounced threshold dependence of interphase death of cells upon their concentration may be attributed to hypoxia occurring in a pericellular medium when cells concentration exceeds the threshold.
Subject(s)
Carcinoma, Ehrlich Tumor/pathology , Culture Media/pharmacology , Interphase/radiation effects , Oxygen/pharmacology , Animals , Carcinoma, Ehrlich Tumor/radiotherapy , Cell Division/drug effects , Cell Division/radiation effects , Cell Survival/drug effects , Cell Survival/radiation effects , Dose-Response Relationship, Drug , Gamma Rays , Hydrogen-Ion Concentration , Interphase/drug effects , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Tumor Cells, CulturedABSTRACT
The influence of different killing inhibiting agents on the interphase death of irradiated rat thymocytes has been investigated. The results confirm the previously proposed hypothesis of the interphase death mechanism involving activation of killing potency in the irradiated population of thymus cells.
Subject(s)
Interphase , Thymus Gland/radiation effects , Animals , Cell Survival/drug effects , Cell Survival/radiation effects , Colchicine/pharmacology , Cytochalasin B/pharmacology , Dimethyl Sulfoxide/pharmacology , Male , Mercaptoethanol/pharmacology , Monensin/pharmacology , Rats , Rats, Inbred Strains , Thymus Gland/cytology , Thymus Gland/drug effectsABSTRACT
A study was made of a change in the content of reduced glutathione (GSH) in Ehrlich ascites tumor (EAT) cells after irradiation with doses evoking their interphase death (ID). GSH content was determined in a suspension of EAT cells fixed by hot ethanol. The postirradiation decrease in the GSH content of the suspension was due to its oxidation by hydrogen peroxide resulting from radiochemical reactions after releasing thereof from cells upon fixation. In the absence of an irradiated medium no changes occurred in the GSH content of EAT cells. It is concluded that ID of EAT cells is not associated with the radiation-induced decrease in the content of GSH, an endogenous antioxidant.
