Comparison of cytopathological changes induced by mercury chloride exposure in renal cell lines (VERO and BGM)

In vitro cytotoxicity assessment of monocationic and dicationic pyridinium-based ionic liquids on HeLa, MCF-7, BGM and EA.hy926 cell lines

Dicationic ionic liquids (ILs) generally possess higher thermal and electrochemical stability than the analogous monocationic ILs, which makes them more suitable for high-temperature applications as solvents for organic reactions, lubricants or stationary phase in gas chromatography. However, knowledge on dicationic IL cytotoxicity is still scarce. Here we explore the cytotoxicity of twelve mono- and dicationic pyridinium-based ILs on HeLa, MCF-7, BGM and EA.hy926 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, cell cycle arrest assays, apoptosis experiments and orange staining were carried out. The results showed that dicationic ILs are generally less cytotoxic than their monocationic counterparts. In monocationic ILs, cytotoxicity was stronger when they contain long alkyl chains, because of their higher lipophilicity. However, the full effect of the length of the linkage alkyl chain of dicationic ILs on cytotoxicity is not clear probably because the chain is "trapped" between both cationic moieties. IL cytotoxicity is highly dependent on the cell type, and HeLa cells exposed to [C₁₂Pyr]Br die via apoptosis. The present study increases our knowledge of IL cytotoxicity on human and monkey cells and clarifies the cell death mechanism. The results suggest that dicationic ILs offer the potential to replace some monocationic ILs because of their lower cytotoxicity.

Induction of reactive oxygen species and apoptosis in BEAS-2B cells by mercuric chloride

Mercury is a widespread environmental and industrial pollutant that induces serious adverse effects in both humans and the environment. However, the toxicities and its mechanisms have not been fully elucidated. Among the proposed mechanisms of biological toxicities, the intracellular level of thiol group (-SH) and oxidative stress have been widely studied. In this study, production of reactive oxygen species (ROS) by mercuric chloride (2, 4, 6, and 8 ppm as of mercury) was investigated in cultured human bronchial epithelial cells (BEAS-2B cell line). Exposure of cultured cells to mercuric chloride led to cell death, ROS increase, and cytosolic caspase-3 activation. The ROS increase was related to the decreased level of GSH. Chromatin condensation evaluated by 4',6-diamidino-2-phenylindole (DAPI) staining were also shown in mercury-treated cells and this suggest the apoptotic process of cells by mercuric chloride.