Avaliação do laser de baixa potencia na expressão de genes relacionado a apoptose

Abstract

INTRODUCTION: Molecular mechanisms knowledge involved in photobiomodulation (FBM) has increased but the gene expression effects, in special genes related with cell death/survival post irradiation are not known yet. So, it is important to know these effects in order to guarantee the safety of therapeutic protocols based on PBM. OBJECTIVE: This study aimed to investigate mRNA levels of genes related with proteins involved in cell death/survival pathways of healthy tissues from mice talocrural joint post PBM. METHODOLOGY: Mice were divided into 3 groups: control, PBM at 3J/cm-2 and PBM at 30J/cm-2. Laser parameters were: wavelength 830 nm, Power output of 10 mW, laser beam area 0.05 cm2, doses 3Jcm-2 e 30Jcm-2 exposure time 15s e 150s, respectively. The irradiations were performed for 4 consecutive days using continuous light emission mode. Analysis of mRNA levels for FasL, Fas, Bax, Apaf-1, Caspase-9, Caspase-3, Caspase-6, Bcl-2 and DNA fragmentation were performed for a possible induction of cell death at the doses tested. RESULTS: PBM may increase mRNA levels of proapoptotic genes; however DNA fragmentation was not observed for both doses tested. On the other hand, mRNA level of the anti-apoptotic Bcl-2 gene was not significantly altered and the Bcl-2 / Bax ratio (protective molecular response indicator) was reduced post PBM at 30Jcm-2. CONCLUSION: Results obtained in this study indicate that PBM by low-level infrared laser can alter mRNA relative levels of genes involved in cell death pathways. However, these molecular alterations were not able to cause DNA fragmentation in cells in talocrural joint tissues, indicating that infrared laser was not enough to cause cell death.