Quantitative assessment of cell damage in situ: electron microprobe X-ray analysis of model organisms treated with noxious species.

The existing set of methods for assessing toxicity of noxas, based on experiments with whole animals (subclinical toxicity, toxicokinetics, carcinogenity, teratogenity, neurotoxicology etc.) does not provide much information about cellular and subcellular effects such compounds may exert. We suggest to complement the current methodology by combining a traditional morphological observation in an electron microscope with a spectroscopic method of electron microprobe X-ray analysis (or X-ray microanalysis). The latter makes it possible to measure concentrations of chemical elements in individual cells and organelles and effects of noxas can thus be assessed (i) at subcellular level, (ii) directly in situ and (iii) quantitatively. Concentrations of biologically important elements such as phosphorus, sulfur or zinc were measured in individual organelles in both intact and noxa-treated tissues, thus offering a possibility of comparing the effects of various noxious species at subcellular level (with the noxa previously applied to whole tissue or animal). The suggested correlation of analytical and morphological information may also provide new insights into cellular targeting of noxas (and potentially also drugs) as some organelles appear to be much more susceptible to damage than others.