Evaluation of cytotoxicity attributed to thimerosal on murine and human kidney cells

Renal inner medullary collecting duct cells (mIMCD3) and human embryonic kidney cells (HEK293) were used for cytoscreening of thimerosal and mercury chloride (HgCl2). Thimerosal and HgCl2 acted in a concentration-dependent manner. In mIMCD3 cells the 24-h LC50 values for thimerosal, thiosalicylic acid, 2,2-dithiosalicylic acid, and 2-sulfobenzoic acid were 2.9, 2200, >1000, and >10,000 microM, respectively. The 24-h LC50 value for HgCl2 in mIMCD3 cells was 40 microM. In HEK293 cells, the 24-h LC50 value for thimerosal was 9.5 microM. These data demonstrate that the higher cytotoxicity produced by thimerosal on renal cells with respect to similar compounds without Hg may be related to this metal content. The present study also establishes mIMCD3 cells as a valuable model for evaluation of cytotoxicity of nephrotoxic compounds.