CO₂ laser increases the regenerative capacity of human adipose-derived stem cells by a mechanism involving the redox state and enhanced secretion of pro-angiogenic molecules

CO₂ laser has a beneficial effect on stem cells by mechanisms that are not clearly elucidated. We hypothesize that the effect of fractional CO₂ laser on human adipose-derived stem cells (ADSC) could be due to changes in redox homeostasis and secretion of factors contributing to cellular proliferation and angiogenic potential. ADSC incubated in medium containing 0.5 or 10 % FBS were exposed to a single irradiation of a 10,600-nm fractional CO₂ laser; non-irradiated ADSC were used as control. Viability/proliferation of ADSC was assessed by MTT assay; the intracellular reactive oxygen species (ROS) levels and the mitochondrial membrane potential (∆Ψ_m) were determined with DCFH-DA and JC-1 fluorescent probes, respectively. Molecules secreted by ADSC in the medium were determined by ELISA assay, and their capacity to support endothelial tube-like formation by the Matrigel assay. The results showed that compared to controls, ADSC kept in low FBS medium and irradiated with CO₂ laser at 9 W exhibited: (a) increased proliferation (∼20 %), (b) transient increase of mitochondrial ROS and the capacity to restore Δψ_m after rotenone induced depolarization, and (c) augmented secretion in the conditioned medium of MMP-2 (twofold), MMP-9 (eightfold), VEGF (twofold), and adiponectin (∼50 %) that have the capacity to support angiogenesis of endothelial progenitor cells. In conclusion, the mechanisms underlying the benefic effect of CO₂ laser on ADSC are the activation of the redox pathways which increases cell proliferation and enhances secretion of angiogenic molecules. These results explain, in part, the mechanisms involved in the increased regenerative potential of CO₂ laser-exposed ADSC that could be exploited for clinical applications.