MTT test

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Microtiter plate of an MTT assay

The MTT test is a test used to determine the metabolic activity of cells. Since this correlates strongly with cell viability under certain conditions , the MTT test is often used to evaluate this.

principle

Cells are treated in vitro with the eponymous dye , a yellow tetrazolium salt , in order to measure their viability or the proportion of living cells in comparison to a control sample of cells. This is necessary, for example, after testing a toxic substance.

The proof of cell vitality by means of the MTT test is based on the reduction of the yellow, water-soluble dye 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) into a blue-violet, water-insoluble formazan . It used to be assumed that MTT was reduced by mitochondrial succinate dehydrogenases , but studies in recent years suggest that the reduction is mainly dependent on the pyridine-containing reducing equivalents NADH and NADPH and only partially on succinate. The amount of the converted and ultimately measured dye thus corresponds to the glycolysis rate of the cells per se and is therefore less of a measure of cell respiration (as previously assumed). The reduction of MTT by NADH and NADPH is dependent on enzymes of the endoplasmic reticulum (ER). The partial reduction of MTT by succinate in the mitochondria, on the other hand, depends on the enzyme succinate dehydrogenase (mitochondrial complex II).

MTT reaction.svg

literature

  • T. Mosmann: Rapid colorimetric assay for cellular growth and survival: Application to proliferation and cytotoxicity assays. In: Journal of Immunological Methods. Volume 65, 1983, pp. 55-63. PMID 6606682 .
  • MV Berridge, AS Tan, KD McCoy, R. Wang: The Biochemical and Cellular Basis of Cell Proliferation Assays That Use Tetrazolium Salts. In: Biochemica. 1996. (PDF)
  • MV Berridge, AS Tan: Characterization of the Cellular Reduction of 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT): Subcellular Localization, Substrate Dependence, and Involvement of Mitochondrial Electron Transport in MTT Reduction. In: Archives of Biochemistry and Biophysics . Volume 303, 1993, pp. 474-482.