Report No DWI0031
THE USE OF CYTOTOXICITY ASSAYS FOR THE ASSESSMENT OF TOXICITY (EHT 9329) Final Report to the Department of the Environment DoE 1823-M/3 PECD 7/7/168
Tissue culture has been used in biology since the beginning of this century and its application to toxicity testing has been of increasing interest over recent years. Cytotoxicity assays using cells in tissue culture may provide one answer to the problem of assessing the biological activity of complex mixtures in environmental pollution.
The cytotoxicity assays presently used for screening leachates from materials should be considered more critically to determine precisely what they will measure, whether they can be improved or whether they should be specified for use only with certain materials.
The development of cytotoxicity assays based on cell culture is very fragmented and suffers from too much duplication of simple experimental work. Their role in toxicology and the development of alternatives to laboratory animals is being hindered by this fragmentation. It is recommended that this be better co-ordinated and further fundamental research into cells in culture, particularly in toxicology, be carried out.
IV RESUME OF CONTENTS
Practical studies on the performance of in vitro cytotoxicity assays and their use for screening water and effluent samples, materials used in water supply and the hepatotoxin of Microcystis aeruginosa are described.
Of the assays examined, cloning efficiency appeared to be the most sensitive while assessment of cell morphology was the least sensitive. The period of exposure to toxins was found to be extremely important, the cells requiring extended exposure to some toxins before evidence of cytotoxicity was observed.
The cytotoxicity assays examined appeared to have little value in examining drinking water but may have some uses in screening effluents where the concentration of toxins is higher. The assays showed substantial variation in sensitivity to the toxic components which leach from materials in contact with water. It is therefore shown to be necessary to define the purpose and limitations of such assays to prevent over interpretation of results by non-specialists.
Toxin producing blooms of the blue-green alga Microcystis aeruginosa were shown to be detectable by means of a cytotoxicity assay rather than by the current methods using laboratory animals.
The value of cytotoxicity assays is restricted by the relative lack of development of such assays at the present time, the unpredictability of problems in their use and the lack of xenobiotic metabolism in cell lines.
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