The effects of indomethacin on tendon-derived cell proliferation using the Alamar Blue assay was
studied. It was demonstrated that tendons appear to contain two subpopulations of cells; one subpopulation with apparently normal metabolic activity and a second subpopulation of cells with low levels of mitochondrial enzymes and subsequently low levels of oxidative metabolism. Although it was also concluded that the Alamar Blue dye had no toxic effect on these cells, because of the differential metabolic rate of tendon-derived cells, reduction of Alamar Blue dye may appear to be non-linear. These findings suggest that the Alamar Blue assay may not be appropriate for studying proliferation in tendon-derived cells