Inhibitory Synergistic Effect of 830nm LASER Radiation and Serum‐Rich in Growth Factors on Viability of Human Fibroblasts In Vitro

LASER radiation (LR) at the wavelength (λ) of 830 nm and serum‐rich in growth factor (SRGF) derived from platelet rich plasma (PRP) are used clinically as biostimulating agents in tissue repair. In contrast, the influence of the synergistic effects of these therapeutics tools on cellular activity are unknown. For this purpose, a protocol was designed to evaluate, in vitro , the isolated and synergistic biomodulatory action of 830 nm LR and SRGF on viability of human fibroblasts (GM07492 cell line). Samples of blood from a male volunteer were submitted to a double centrifugation protocol (400g‐10min./700g‐17min.) to obtain the PRP, posteriorly activated with human thrombin solution (10,000 IU) and calcium chloride (10% m/v) to obtain SRGF. In order, to analyze the influence of LR on the wavelength (λ) of 830nm, continuous emission mode, energy density of 0.3J/cm 2 and irradiance of 18mW/cm 2 were established. Cells were grown in 24 well plates (3×10 4 cells/well) in Dulbecco's Modified Eagle Medium (DMEM), supplemented with fetal bovine serum (FBS‐2.5%), SRGF (2.5%) or combination of both. The cell viability rate was determined in each of these culture conditions, associated or not to LR, using the MTT‐Formazan colorimetric method. The analyzes were performed 24 hours after irradiation and the viability (triplicate) expressed in percentage in relation to the control condition (FBS‐2.5%). The data were submitted to analysis of variance (ANOVA) supplemented by Fisher's post‐test, considering a significance level of 5% (p≤0.05). The platelet counts in PRP showed a concentration of 1.7×10 6 /μL of plasma. The results regarding cell viability demonstrated that SRGF exerted a biostimulating effect on cells, considering a 27% increase in viability rate when used alone and 116% when associated with FBS. LR at λ also exerted a biostimulating effect on cells cultured in the control condition and with SRGF alone, providing a 164 and 142% increase in cell viability rate, respectively. In contrast, the synergistic action of radiation and SRGF associated with FBS determined a bioinhibitory effect in the cells, considering the reduction of 53% in the viability rate in relation to the cells in the same culture conditions and without the radiation. The association of these availability sources of growth factors (GF) were used to simulate, in vitro, the therapeutic use of PRP, providing more growth factors into the repair site. The results allow us to conclude that both 830 nm LR and SRGF have an in vitro biostimulating effect on viability of human fibroblasts when they act in isolation and that the synergistic influence of SRGF and LR promote a significant bioinhibitory cellular effect that could compromise the therapeutic benefits sought in a tissue repair process when they are used. Support or Funding Information Coordenação de Aperfeiçoamento de Pessoal de Nível Superior This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .