TOXICITY OF 10 MEIC CHEMICALS TO MITOCHONDRIA BY FLUORESCENCE IMAGING

XINHAI WANG1, KEN-ICHI HIRANO2, YOSHIRO KOBAYASHI3, KAORU SAIJO1 and TADAO OHNO1
1RIKEN Cell Bank, The Institute of Physical and Chemical Research (RIKEN), 3-1-1 Koyadai, Tsukaba Science City, Ibaraki 305, Japan; 2Tsukuba Research Laboratory, Hamamatsu Photonics Co., Ltd., 5-9-2 Tokodai, Tsukuba Science City, Ibaraki 300-26, Japan; 3Department of Biomolecular Science, Faculty of Sciences, Toho University, 2-2-1 Miyama, Funabashi City, Chiba 274, Japan

Regular Article :AATEX 3(3):85-93

Abstract
The in vitro toxicity of 10 MEIC chemicals was determined using a fluorescence microscope-video camera-image processor system. Human lung carcinoma cells were loaded with rhodamine 123 which accumulates specifically in mitochondria in living cells. Rhodamine 123 fluorescence in mitochondria relative to that in the cytoplasm of the cells was measured after 3 hour treatment with the MEIC chemicals. Results showed that the ED50 values of the chemicals determined by this method were highly correlated with the corresponding values determined by the MTT (r=0.949) and lactate dehydrogenase-release assays (r=0.948) after 48 hours. This fluorescence-image processing was faster for measuring changes in mitochondrial function than the MTT assay, and is useful for measuring the direct toxic effects of chemicals on organelle's functions in situ.


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