Effects in vitro of cadmium ions on some membrane and nuclear parameters of normal and irradiated thymic lymphoid cells.

Effects of cadmium chloride upon 3H-Con A binding, number of autologous rosette-forming cells (ARFC), cell viability and the degree of DNA supercoiling were studied in normal and irradiated thymic lymphoid cells, isolated from rats and incubated up to 6 h in vitro. Cd (10-100 microM) did not significantly alter the patterns of surface markers and viability of normal thymocytes, as measured by supravital staining or nuclear pyknotic criteria. The following effects of Cd were noted for irradiated thymic cells: 1) Cd ions (25 microM) caused elimination of radiation-induced increase of Con A binding; 2) the characteristic loss of ARFC receptors, like development of nuclear pyknosis, was prevented in the presence of CdCl2 (10-100 microM); 3) the postradiation relaxation of nuclear supercoiled DNA was distinctly less pronounced with Cd. Possible reasons for these effects of Cd are discussed. Irradiated lymphoid cells are proposed as a suitable experimental model for the studies of different toxic actions of Cd and other heavy metals.