One of the most urgent needs in surgery today is a method of determining the viability of tissue known to be ischemic. All tissue can survive a varying period without blood supply, but at some point cellular death ensues. After this time, revascularization would be fruitless. 3-(4,5-Dimethylthiazol-2-yl) -2,5-diphenyl-2H-tetrazolium bromide (MTT) is a dye which is reduced by dehydrogenase enzymes found in living cells. As the dye is reduced, its color changes from yellow to dark blue. The rapidity with which the change occurs has been correlated with cell viability. Terasaki et al1 first used this dye to evaluate cadaveric kidneys for transplantation purposes, reporting that it was a simple method of determining the viability of donor organs.
In the present experiment, canine ileum was subjected to various periods of total avascularity, and serial tests with the dye were performed. Our results showed a definite correlation between MTT dye times
Carter K, Halle M, Cherry G, Myers MB. Determination of the Viability of Ischemic Intestine. Arch Surg. 1970;100(6):695-734. doi:10.1001/archsurg.1970.01340240063014