A microtiter plate assay for superoxide using MTT reduction method.

A simple, rapid and sensitive microtiter plate assay for superoxide using the reduction of tetrazolium dye MTT to its coloured formazan has been developed. The colour formed can be measured using a microtiter plate reader and the extent of reduction of MTT indicates the amount of superoxide generation. A comparison of the sensitivities of different procedures for the quantitation of superoxide generated by X-XO system has been made. The MTT reduction due to superoxide was confirmed by inhibiting the reduction using purified superoxide dismutase. Using this method superoxide generation by mitochondria and microsomes was demonstrated and this procedure is suitable for detection of intracellularly generated superoxide. The proposed method is inexpensive and is suitable for a routine analysis of large number of samples.