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Previous studies have discussed an inverse correlation between age and wound healing, because it relates to the association of aging with a gradual decrease in healing capacity. Treatment with photobiomodulation therapy (PBMT) improves wound healing by inducing increases in mitotic activity, numbers of fibroblasts, collagen synthesis, and neovascularization. Therefore, this study aimed to evaluate the effects of PBMT in cutaneous wound healing in aged rats. A punch biopsy of 8 mm in diameter was performed to produce a skin wound. The study included 45 male rats, of which 15 were young (30 days) and 30 were elderly (500 days). The 45 animals were distributed into 3 experimental groups, which were subjected to skin wounds and 1 aged group received PBMT, with a 30-mW laser beam (power density of 1.07 W/cm2), beam area of 0.028 cm2, and λ660 nm produced through active phosphide Gallium-Aluminum-Indio (InGaAIP). The PBMT application took the form of a single-point transcutaneous method, with a total energy of 2 joules per wound site, energy density of 72 J/cm2, and time of 1 min and 7 s. Analysis was performed to verify the effect of PBMT on the quantity of collagen I and III, metalloproteinase 3 and 9 (MMP-3 and MMP-9), tissue inhibitor of metalloproteinase-2 (TIMP-2) and of vascular endothelial growth factor (VEGF) at the wound site by immunohistochemistry, cytokine-induced neutrophil chemoattractant (CINC)-1, by enzyme-linked immunosorbent assay (ELISA) and interleukin (IL)-6 real-time polymerase chain reaction (RT-PCR). That we conclude LLLT is effective in the modulation of inflammatory mediators IL-6, CINC-1, VEGF, MMP-3, MMP-9 and TIMP-2 as well as increased collagen production in aged animals during different phases of the tissue regeneration process. However, the effects of PBMT obtained in the aged animals (aged LLLT group) suggest that new dosimetries should be tested to achieve better results. [ABSTRACT FROM AUTHOR]

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by chronic and systemic inflammation, which leads to the destruction of the cartilage and bone and affects tissues in multiple joints. Oxidative stress has been implicated with regards to involvement in various disease conditions, such as diabetes mellitus and neurodegenerative, respiratory, cardiovascular, and RA diseases. In vivo experimental studies using photobiomodulation therapy (PBMT) have shown positive effects in reducing lipid peroxidation and in increasing antioxidant activity. The regular practice of physical exercise has also been reported to be a beneficial treatment capable of reducing oxidative damage. Thus, the aim of this study was to analyze the effects of photobiomodulation therapy at 2- and 4-J doses associated with physical exercise on oxidative stress in an experimental model of RA in protein expression involving superoxide dismutase (SOD), glutathione peroxidase (GPX), and/or catalase (CAT) on thiobarbituric acid reactive substances (TBARS). In this study, 24 male Wistar rats divided into four groups were submitted to an RA model (i.e., collagen-induced arthritis, CIA), with the first immunization performed at the base of the tail on days 0 and 7 were included. After 28 days, a third intraarticular dose was administered in both knees of the animals. After the last induction, PBMT was started immediately, transcutaneously at two points (i.e., the medial and lateral), with a total of 15 applications. Treadmill exercise was also started the day after the last induction, and lasted for 5 weeks. With respect to results, we obtained the decreases in the lipid peroxidation and the increases of the antioxidant activities of SOD, GPX and CAT, with physical exercise associated to PBMT in doses of 2 and 4 J. In conclusion, physical exercise associated with PBMT decreases lipid peroxidation and increases antioxidant activity. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether photobiomodulation therapy (PBMT) could improve the bioavailability and chondroprotective benefits of mesenchymal stem cells injected into the knees of rats used as an experimental model of osteoarthritis (OA) as well as reduce the expression of matrix metalloproteinases (MMPs) and degradation of type II collagen (COL2-1) in the cartilage. Adipose-derived stem/stromal cells (ADSCs) were collected from three male Fischer 344 rats and characterized by flow cytometry. Fifty female Fischer 344 rats were distributed into five groups of 10 animals each. These groups were as follows: control, OA, OA PBMT, OA ADSC, and OA ADSC PBMT. OA was induced in the animals using a 4% papain solution. Animals from the OA ADSC and OA ADSC PBMT groups received an intra-articular injection of 10 × 106 ADSCs and were treated with PBMT by irradiation (wavelength: 808 nm, power: 50 mW, energy: 42 J, energy density: 71.2 J/cm2, spot size: 0.028). Euthanasia was performed 7 days after the first treatment. The use of PBMT alone and the injection of ADSCs resulted in downregulation of pro-inflammatory cytokines and MPs in cartilage compared to the OA group. PBMT and ADSCs caused upregulation of tissue inhibitors of MPs 1 and 2 and mRNA and protein expression of COL2-1 in cartilage compared to the OA group. The intra-articular injection of ADSCs and PBMT prevented joint degeneration resulting from COL2-1 degradation and modulated inflammation by downregulating cytokines and MMPs in the OA group. [ABSTRACT FROM AUTHOR]

The present study aimed to determine if LLLT restores the balance between mRNA expression of matrix metalloproteinases (MMP-2 and MMP-9) and also the balance between collagen types I and III during the healing process of diabetic wounds. One hundred and twenty male Wistar rats were distributed in Control (untreated non-diabetic rats: UND); Laser (laser treated in non-diabetic rats: LTND); Diabetic (diabetic rats non-laser treated rats: UD); and Diabetic+ Laser (diabetic rats laser treated: DLT) groups. The diabetes model using streptozotocin efficiently induced diabetes, as demonstrated through increased levels of blood glucose. Diode laser (50 mW, 660 nm, 4 J/cm2, 80 s) was applied a single time after scare induction. Twenty-four hours after LLLT application, rats were euthanized, the scarred areas were collected for MMP-2 and MMP-9 mRNA analysis and also for histological analysis (inflammation and types I and III collagen). The results demonstrated that scare in untreated diabetic rats significantly increased the MMP-2 and MMP-9 expression compared with that in non-diabetic rats (p < 0.05), while LLLT significantly reduced MMP-2 and MMP-9 expression compared with that in untreated diabetic rats (p < 0.05). To conclude, the results also showed that LLLT was able to alter the expression of MMP-9 as well as accelerate the production of collagen and increase the total percentage of collagen type III in diabetic animals. [ABSTRACT FROM AUTHOR]