New Research
PULSED LLLT IMPROVES TENDON HEALING IN RATS: A BIOCHEMICAL, ORGANIZATIONAL, AND FUNCTIONAL EVALUATION
Guerra FD, Vieira CP, Dos Santos de Almeida M, Oliveira LP, Claro AC, Simões GF, de Oliveira AL, Pimentel ER.
Source:
Department of Structural and Functional Biology, Institute of Biology, University of Campinas-UNICAMP, CP 6109, 13083-970, Campinas, SP, Brazil, dgflavia@yahoo.com.br.
Abstract
In the last decades, the tendon injuries have increased substantially. Previous results suggested that low-level laser treatment (LLLT) promotes synthesis of extracellular matrix and improves the functional properties of the tendon. The aim of this study was to evaluate the effects of different protocols of LLLT on partially tenotomized tendons. Adult male rats were divided into the following: G1-intact, G2-injured, G3-injured+LLLT (4 J/cm2 continuous), G4-injured+LLLT (4 J/cm2 at 20 Hz). G2, G3, and G4 were euthanized 8 days after injury. G5-injured, G6-injured+LLLT (4 J/cm2 continuous), and G7-injured+LLL (4 J/cm2 at 20 Hz until the seventh day and 2 kHz from 8 to 14 days). G5, G6, and G7 were euthanized on the 15th day. Glycosaminoglycan (GAG) level was quantified by dimethylmethylene blue method and analyzed on agarose gel. Toluidine blue (TB) stain was used to observe
metachromasy. CatWalk system was used to evaluate gait recovery. Collagen organization was analyzed by polarization microscopy. The GAG level increased in all transected groups, except G5. In G6 and G7, there was a significant increase in GAG in relation to G5. In G3 and G4, the presence of dermatan sulfate band was more prominent than G2. TB stains showed intense metachromasy in the treated groups. Birefringence analysis showed improvement in collagen organization in G7. The gait was significantly improved in G7. In conclusion, pulsed LLLT leads to increased organization of collagen bundles and improved gait recovery.
(Lasers Med Sci. 2013 Aug 28. [Epub ahead of print])
Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/23982719
______________________________________________________
EFFECTS of LOW-LEVEL LASER THERAPY (GaAs) IN AN ANIMAL MODEL OF MUSCULAR DAMAGE INDUCED BY TRAUMA
Silveira PC, da Silva LA, Pinho CA, De Souza PS, Ronsani MM, Scheffer Dda L, Pinho RA.
Source:
Laboratório de Fisiologia e Bioquímica do Exercício, Universidade do Extremo Sul Catarinense, Av. Universitária, 1105-Bairro Universitário, 88806-000, Criciúma, SC, Brazil, silveira_paulo2004@yahoo.com.br.
Abstract
It has been demonstrated that reactive oxygen species (ROS) formation and oxidative damage markers are increased after muscle damage. Recent studies have demonstrated that low-level laser therapy (LLLT) modulates many biochemical processes mainly those related to reduction of muscular injures, increment of mitochondrial respiration and ATP synthesis, as well as acceleration of the healing process. The objective of the present investigation was to verify the influence of LLLT in some parameters of muscular injury, oxidative damage, antioxidant activity, and synthesis of collagen after traumatic muscular injury. Adult male Wistar rats were divided randomly into three groups (n=6), namely, sham (uninjured muscle), muscle injury without treatment, and muscle injury with LLLT (GaAs, 904 nm). Each treated point received 5 J/cm(2) or 0.5 J of energy density (12.5 s) and 2.5 J per treatment
(five regions). LLLT was administered 2, 12, 24, 48, 72, 96, and 120 h after muscle trauma. The serum creatine kinase activity was used as an index of skeletal muscle injury. Superoxide anion, thiobarbituric acid reactive substance (TBARS) measurement, and superoxide dismutase (SOD) activity were used as indicators of oxidative stress. In order to assess the synthesis of collagen, levels of hydroxyproline were measured. Our results have shown that the model of traumatic injury induces a significant increase in serum creatine kinase activity, hydroxyproline content, superoxide anion production, TBARS level, and activity of SOD compared to control. LLLT accelerated the muscular healing by significantly decreasing superoxide anion production, TBARS levels, the activity of SOD, and hydroxyproline content. The data strongly indicate that increased ROS production and augmented collagen
synthesis are elicited by traumatic muscular injury, effects that were significantly decreased by LLLT.
(Lasers Med Sci. 2013 Feb;28(2):431-6. doi: 10.1007/s10103-012-1075-6. Epub 2012 Mar 8)
Retrieved from: http://www.ncbi.nlm.nih.gov/pubmed/22399243
