Comparison of Mitochondrial Fluorescent Dyes in Stromal Cells

Specific fluorescent mitochondrial dyes JC-1, MitoTracker Red FM, and MitoTracker Red CMXRos were studied on cultures of mesenchymal stromal stem cells from human adipose tissue. Static and dynamic experiments demonstrated the dependence of dye accumulation in the mitochondria and cytoplasm on mitochondrial potential in the presence of oxidative phosphorylation uncoupler CCCP. JC-1 dye demonstrated most pronounced bleaching upon repeated laser exposure even in very low doses, which should be taken into account when planning dynamic experiments on live cells. Moreover, this dye requires two-wave recording in red and green spectral bands. MitoTracker Red FM and MitoTracker Red CMXRos are resistant to bleaching, but for the latter, the intensity of fluorescence reflects not only the mitochondrial potential. MitoTracker Red CMXRos covalently binds to sulfhydryl groups in mitochondrial lipids and proteins, which can lead to misinterpretation of the fluorescence intensity–mitochondrial potential dependence.