Efeitos da fotobiomodulação em metaloproteinases e seu regulador na articulação talocrural de camundongos

Abstract

Introduction: Photobiomodulation (PBM) has been widely described in the literature with excellent results involving resolution of inflammatory processes, pain relief and tissue repair. PBM has been applied in several experimental and clinical researches due to low cost, athermic effect and painless. However, it is not known about possible side-effects and unwanted cellular responses. Since anti-inflammatory drugs have elucidations about their side-effects, it is also important to know about these possible side-effects in phototherapy. Objective: The aim of this study was to evaluate the metalloproteinase-2, -9 and -13 mRNA relative levels as well as its regulator (TIM-2) and protein expressions of MMP-13 and TIMP- 2 in healthy tissues present in mice talocrural joint after PBM. Methods: Animals were divided into 3 groups (n = 6): control, 3Jcm-2 e 30Jcm-2. Low –level laser parameters were: 830 nm, 10 mW, 0.05 irradiated area, doses of 3Jcm-2 and 30Jcm-2, 15 and 150 seconds of irradiation, respectively, and continuous mode. The joints were irradiated for 4 consecutive days once a day. After euthanasia, the left joints were dissected and RNA extracted to quantify metalloproteinases mRNA levels (MMP-2, MMP-9, MMP-13) and its regulator (TIMP-2) by real time PCR. Right joints were dissected to immunocytochemestry analysis for MMP-13 and TIMP-2. Results: An increase in MMP-2 mRNA relative levels was observed at 30Jcm-2 group (p <0.05), while MMP-9, MMP-13 and TIMP-2 mRNA relative levels were not demonstrate statistical differences for any group (p> 0.05). Regarding protein expressions, MMP-13 demonstrated positive labeled cells, but only in chondrocytes from articular cartilages, although the cell quantification has not demonstrated statistical differences when compared with control group (p> 0.05). TIMP-2 did not present positive labeled cells for any tissues evaluated. Conclusion: Our results indicate that PBM was able to regulate mRNA levels for MMP-2, but it was not able to regulate MMP-13 and TIMP-2 proteins and this regulation was dose-dependent.