Cytotoxicity of dinitrotoluenes (2,4-dNT, 2,6-DNT ) to MCF-7 and MRC-5 cells.

DNTs are considered possibly carcinogenic to humans (Group 2B) because there is inadequate evidence in humans for carcinogenicity though there is sufficient evidence in experimental animals. In this study, MCF-7 (breast) and MRC-5 (lung) cells were exposed to a serial dilution of 2,4 and 2,6 DNTs (control, 1-500 ppm) in 96 well tissue culture plates. After various time intervals (24, 48, 72 and 96 hrs) the plates were washed, and 100microl fluorescein diacetate solution (10 microg/ml in PBS) was added column wise to each well, and incubated at 37 C for 30 - 60 min before reading the fluorescence with a spectrofluorometer at excitation and emission wavelengths of 485 and 538 nm respectively.