Fluorometric determination of the redox state and distribution of mitochondria in human malignant glioblastoma cells grown on different culturing substrates

Objectives: To evaluate the redox state and the spatial distribution of mitochondria in malignant human brain cancer cells grown on different substrates. Methods: Cellular autofluorescence images were obtained through an inverted fluorescence microscope and the redox fluorometric ratio was evaluated (after the subtraction of background) as the net fluorescence signal through the DAPI filter divided by the net fluorescence signal through the FITC filter. Spatial mitochondria distribution patterns were evaluated by division of the cell area at the midpoint between the nuclear and cell membranes. The average fluorescence in the central area (CF) was divided by the average fluorescence from the peripheral area (PF). The CF/PF ratios were compared between cells cultured on either poly-d-lysine or collagen I substrates. Results: Glioblastoma cells seeded on the collagen-coated plates were observed to proliferate ∼33-50% faster than the cells seeded on the poly-d-lysine-coated plates. Consistent with the proliferation findings, the redox ratios were lower for the cells seeded on the collagen-coated plates compared with poly-d-lysine. However, cell size and the percentage of cells with perinuclear mitochondrial distribution were not observed to be different in the cells seeded on the two surfaces. Conclusions: Redox ratio computation by using redox fluorometry is a useful predictor of cellular proliferation.