Mitochondrial membrane potential after low-power laser irradiation.

We used the lipophilic cationic fluorescent dye 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-benzimidazol-carbocyanine iodide (JC-1) to determine mitochondrial membrane potential (mdeltapsi) in Hep-2 cells after irradiation with low-power laser (lambda=635 nm). Through this methodology it was possible to analyze the variation on mitochondrial number and mdeltapsi, in cells irradiated for 100, 150 and 200 s with energy density of 100 mJ/cm(2). Our results show that JC-1 dye allows the identification of populations with different mitochondria morphology as well as the functionality of this organelle in the cells incubated for 1, 6 and 24 h, after irradiation with low-power laser.