Chromatin changes induced by Pb and Cd in human cells

Our earlier data on the apoptotic effects of heavy metals (Cd, Hg, Ni, CrVI, and Ag) and irradiation (gamma and UV-B) indicated that cellular effects exerted on chromatin structure differ from one other. These observations suggested that chromatin distortions could be characteristic to the genotoxic agent. This notion raised questions whether or not (a) a specific genotoxic agent causes the same chromatin changes in different cell types, (b) closely related toxic compounds could be distinguished based on their chromatin toxicity. To answer these questions we have compared Cd induced toxicity in different cell types. The same Cd-specific chromatin changes were seen in human K562, Chinese hamster ovary and murine preB cells. K562 cells were chosen for fluorescent microscopy to compare chromatin damages caused by Cd and Pb. Characteristic distortions allowed a clear distinction between Cd and Pb toxicity at micromolar concentrations. The visualization of these changes is relatively easy and fast carrying the potential of early detection of heavy metal poisoning.