Apoptogenic and necrogenic effects of mercuric acetate on the chromatin structure of K562 human erythroleukemia cells

Time lapse video photography was used to follow the movement of individual cells after in vitro treatment with Hg(II) acetate. Cellular changes of mercuric ions were characterized by their properties of causing reduced cellular mobility (10–50 μM), and complete lack of cellular movement at higher concentrations (100–1000 μM). Results show that after mercury treatment at subtoxic levels (?1 μM): (a) chromatin changes were the earliest signs of cytotoxicity, (b) two major parts in nuclear material of K562 erythroleukemia cells could be distinguished, highly condensed supercoiled and decondensed veil-like chromatin, (c) decondensed chromosomes were rejected as clustered puffs and (d) often the nuclear material was broken down to apoptotic bodies. Nuclear changes caused by Hg(II) acetate in the concentration range between 10 and 50 μM were characterized by apoptosis seen as broken nuclei and apoptotic bodies. High concentration of Hg²⁺ ions (100 μM) initiated necrotic nuclear changes, with enlarged leaky or opened nuclei.