New methods for cytotoxicity testing: quantitative video microscopy of intracellular motion and mitochondria-specific fluorescence.

The aim of this study is to qualify the application the new microscopic methods fluorescence and AVEC-DIC (Allen video-enhanced contrast differential interference contrast) microscopy for toxicity testing. The effects of 2-OH-ethyl methacrylate (HEMA), a toxic acrylic monomer, on human fibroblasts was tested. The HEMA concentrations used were 0.01-1% at incubation times of 1-24 h. The cells were observed with AVEC-DIC microscopy and fluorescent staining to evaluate the velocity of lysosomal movement, the number and morphology of the mitochondria, and the fine structure of the cell. In the samples treated with the toxic compound the lysosomal movement changed, as did the morphology of the mitochondria and of the whole cells. The results are compared and discussed with regard to the results of conventional cytotoxicity tests performed in parallel. The new methods proved to be more sensitive and yielded more specific information on the cellular changes caused by the compound.