Radiation biology. Radioecology
ISSN: 0869-8031

Archives → 2020 → V. 60. №5. → pp. 524–531

Article

Patterns of Synergic Interaction Display after Heavy Metals Combined with Hyperthermia or Ionizing Radiation

M. S. Tolkayeva^a, A. N. Filimonova^b, O. A. Vorobey^a, E. S. Evstratova^b, and V. G. Petin^a

^aA. Tsyb Medical Radiological Research Center – branch of the National Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Obninsk, Russia ^bNational Medical Research Radiological Center of the Ministry of Health of the Russian Federation, Obninsk, Russia

Abstract

The objective of the study was to identify the general patterns of synergism display after simultaneous action of heavy metal salts with ionizing radiation or with hyperthermia. The objects of research were Escherichia coli bacteria (strain B/r) and diploid yeast cells of Saccharomyces cerevisiae (strain XS800), which were treated with chemical preparations containing salts of heavy metals (copper, platinum, lead, chromium, zinc) at the stationary stage of growth simultaneously with hyperthermia (37–60°С) or ionizing radiation (γ-rays 60Co, dose rate 10.8 Gy/min). To demonstrate the generality of the revealed patterns, we used data on the inactivation of Chinese hamster cells (CHO) published by other authors. To quantify the degree of synergism, we used a synergistic enhancement ratio determined by the division of isoeffective doses on the theoretically expected and experimental dose-response curves. Experimental results related with cell survival and the synergistic interaction of the simultaneous application of heavy metal salts with ionizing radiation or hyperthermia are presented. The optimal parameters of acting agents that provide the highest synergistic interaction have been revealed. Any deviation of these parameters from the optimal value leads to a decrease in synergism. It is concluded on the existence of general pattern revealed, which does not depend on the nature of the acting agents, biological objects and tests. Possible mechanisms of the results obtained and directions of their practical application in radiobiology and ecology are discussed.

Keywords

ionizing radiation, heavy metals, hyperthermia, synergism, bacteria, yeast, mammalian cells