Cadmium ions inhibit activity of translation components and induce cell death in mouse liver

Abstract

The aim of this study was to determine a relationship between activity of tRNALeu and leucyl-tRNA synthetase and cell death in cadmium-intoxicated mouse liver. 24 h after intoxication of mice with a sublethal dose of cadmium ions (1.6 mg per 1 kg of body mass) the activity of leucyl-tRNA synthetase decreased by 30%, whereas the acceptor activity of mice liver tRNALeu decreased by 54% as compared to the control. Experiments in vitro showed that the activity of mouse liver tRNALeu and leucyl-tRNA synthetase were reduced by 98% and 70%, respectively, when a 20 µM concentration of cadmium ions was present in the reaction mixtures. It is proposed that tRNA molecule is more sensitive than aminoacyl-tRNA synthetase to cadmium action. According to data of a TUNEL assay, the number of apoptotic (TUNEL+) cells was the same in both Cd-intoxicated livers and control. Agarose-gel DNA electrophoresis revealed a diffusional pattern typical of randomly degraded DNA fragments. It is possible to assume that not apoptosis but rather necrosis is a principal mode for elimination of irreversibly damaged liver cells 24 h following cadmium intoxication. Keywords: cadmium, tRNA, leucyl-tRNA synthetase, apoptosis, necrosis