Method for the description of differences in the filamentous structure of the cytoskeleton in cultured cells

Over the last few years in vitro cell systems have been established for toxicological investigations. These systems permit the evaluation of effects on the basis of cultured cells in order to replace animal studies. Not only qualitative assessment of cytotoxic effects, but also efforts to quantify these intracellular changes have become more and more important to objectify the results which have been obtained. The cytoskeleton, a dynamic and sensitive system, seems to be a valuable morphological parameter to gain information about the intracellular alterations of drug-influenced cells. Depending on the dose of the substance administered, the cytoskeleton shows morphological alterations in specific components, which fulfill structural as well as metabolic regulatory functions and thus provide information on possible mechanisms. Normally, microtubules as well as the intermediate filament system from 3-dimensional networks. Treatment may induce contraction or depolymerization of the filamentous proteins. These alterations, seen in immunofluorescent preparations, can be quantified by means of a 2-dimensional Fourier transformation. As there is no statistical method to compare different spectra, the spatial frequency spectrum of the Fourier components has to be transformed to a 1-dimensional array. This step is performed by measuring the optical density of localised areas in the frequency spectrum. Using this transformation it is possible to compare the Fourier spectra belonging to different treatment groups.