In vitro effect of low-level laser therapy on the proliferative, apoptosis modulation, and oxi-inflammatory markers of premature-senescent hydrogen peroxide-induced dermal fibroblasts.

Skin aging is a complex biological process induced by intrinsic and extrinsic factors which is characterized by clinical and cellular changes, especially dermal fibroblasts. It is possible that, some procedures, such as low-level laser therapy (LLLT), could decelerate this process. To test this hypothesis, this study evaluated the in vitro LLLT on dermal fibroblast cell line (HFF-1) with premature senescence HO-induced. HFF-1 cells were cultured in standardized conditions, and initially HO exposed at different concentrations. Fibroblasts were also just exposed at different LLLT (660 nm) doses. From these curves, the lowest HO concentration that induced indicators of premature senescence and the lowest LLLT doses that triggered fibroblast proliferation were used in all assays. Cellular mortality, proliferation, and the levels of oxidative, inflammatory cytokines, apoptotic markers, and of two growth signaling molecules (FGF-1 and KGF) were compared among treatments. The HO at 50 μM concentration induced some fibroblast senescence markers and for LLLT, the best dose for treatment was 4 J (p < 0.001). The interaction between HO at 50 μM and LLLT at 4 J showed partially reversion of the higher levels of DNA oxidation, CASP 3, CASP 8, IL-1B, IL-6, and INFy induced by HO exposure. LLLT also trigger increase of IL-10 anti-inflammatory cytokine, FGF-1 and KGF levels. Cellular proliferation was also improved when fibroblasts treated with HO were exposed to LLLT (p < 0.001). These results suggest that in fibroblast with some senescence characteristics HO-induced, the LLLT presented an important protective and proliferative action, reverting partially or totally negative effects triggering by HO.