Laser photobiomodulation of pro-inflammatory mediators on Walker Tumor 256 induced rats.

Laser photobiomodulation or low-level laser therapy (LLLT) is recognized worldwide for its expansive use in medicine. LLLT has been reported to increase enzymatic activity, increasing the mitochondrial transmembrane potential, leading to an increased energy availability and signal transduction. Nevertheless, an inhibitory effect is also observed by the production of excessive ROS which can result the shutdown of mitochondrial energy production, and finally to apoptosis. However, the mechanism of apoptosis induced by LLLT is still not well understood. The main objective of the present study was to investigate the hypothesis that LLLT induces oxidative stress and stimulates the generation of pro-inflammatory markers interfering in tumor progression. METHODS: Seventy-two female Walker Tumor induced Wistar rats (eight weeks of age, 200g body weight) were used for this study. TW-256 cells were suspended in phosphate buffered saline and then subcutaneously inoculated at 1×107viabletumorcells/ml per rat into the right flank (tumor-bearing rats). After a period of 14days in order to assess the development of the solid tumor mass, the animals were randomized and distributed in four groups (n=8 animals/group): (1) Control or irradiated by LLLT (2) Laser 1J - 35,7J/cm2, (3) Laser 3J - 107,14J/cm2 and (4) Laser 6J - 214,28J/cm2; (Thera Laser - 660nm, 100mW DMC®, São Carlos, Brazil) at four equidistant points according to their respective treatment groups, conducted three times on alternate days. The regulation and expression of inflammatory mediators IL-1ß, IL-6, IL-10, TNF-α was assessed by ELISA and gene expression of COX-1, COX-2, iNOS, eNOS was analyzed by RT-PCR. RESULTS: We found that the 1Joule (J) treated group promoted a significant increase in the levels of different inflammatory markers IL-1ß, the gene expression of COX-2, iNOS, which was statistically different (p<0.05) when compared among different treatment and control groups. With Respect IL-6, IL-10, TNF-α levels statistically significant reduce was observed in 1Joule treated group when comparing to different energies groups and control group. CONCLUSION: Our results suggest the evidence 1J-35,7J/cm2 treatment was able to produce cytotoxic effects by generation of ROS causing acute inflammation and thus may be employed as the best energy dose associated with Photodynamic Therapy.

Effects of low-level laser therapy (LLLT) and diclofenac (topical and intramuscular) as single and combined therapy in experimental model of controlled muscle strain in rats.

Muscle injuries represent ca 30% of sports injuries and excessive stretching of muscle causes more than 90% of injuries. Currently the most used treatments are nonsteroidal anti-inflammatory drugs (NSAIDs), however, in last years, low-level laser therapy (LLLT) is becoming an interesting therapeutic modality. The aim of this study was to evaluate the effect of single and combined therapies (LLLT, topical application of diclofenac and intramuscular diclofenac) on functional and biochemical aspects in an experimental model of controlled muscle strain in rats. Muscle strain was induced by overloading tibialis anterior muscle of rats. Injured groups received either no treatment, or a single treatment with topical or intramuscular diclofenac (TD and ID), or LLLT (3 J, 810 nm, 100 mW) 1 h after injury. Walking track analysis was the functional outcome and biochemical analyses included mRNA expression of COX-1 and COX-2 and blood levels of prostaglandin E2 (PGE2 ). All treatments significantly decreased COX-1 and COX-2 gene expression compared with injury group (P < 0.05). However, LLLT showed better effects than TD and ID regarding PGE2 levels and walking track analysis (P < 0.05). We can conclude that LLLT has more efficacy than topical and intramuscular diclofenac in treatment of muscle strain injury in acute stage.

Endothelium-Dependent Vasorelaxant Effect of Butanolic Fraction from Caryocar brasiliense Camb. Leaves in Rat Thoracic Aorta.

Caryocar brasiliense Camb. "pequi" is a native plant from the Cerrado region of Brazil that contains bioactive components reported to be antioxidant agents. Previous work has demonstrated that dietary supplementation with pequi decreased the arterial pressure of volunteer athletes. We found that the crude hydroalcoholic extract (CHE) of C. brasiliense leaves relaxed, in a concentration-dependent manner, rat aortic rings precontracted with phenylephrine, and that the butanolic fraction (BF) produced an effect similar to that of the CHE. Aortic relaxation induced by BF was abolished by endothelium removal, by incubation of the nitric oxide synthase inhibitor L-NAME, or the soluble guanylatecyclase inhibitor ODQ. However, incubation with atropine and pyrilamine had no effect on the BF-induced vasorelaxation. Moreover, this effect was not inhibited by indomethacin and tetraethylammonium. The concentration-response curve to calcium in denuded-endothelium rings was not modified after incubation with BF, and the vasorelaxation by BF in endothelium-intact rings precontracted with KCl was abolished after incubation with L-NAME. In addition, administration of BF in anesthetized rats resulted in a reversible hypotension. The results reveal that C. brasiliense possesses both in vivo and in vitro activities and that the vascular effect of BF involves stimulation of the nitric oxide/cyclic GMP pathway.

Low-level laser therapy in collagenase-induced Achilles tendinitis in rats: analyses of biochemical and biomechanical aspects.

NSAIDs are widely prescribed and used over the years to treat tendon injuries despite its well-known long-term side effects. In the last years several animal and human trials have shown that low-level laser therapy (LLLT) presents modulatory effects on inflammatory markers, however the mechanisms involved are not fully understood. The aim of this study was to evaluate the short-term effects of LLLT or sodium diclofenac treatments on biochemical markers and biomechanical properties of inflamed Achilles tendons. Wistar rats Achilles tendons (n = 6/group) were injected with saline (control) or collagenase at peritendinous area of Achilles tendons. After 1 h animals were treated with two different doses of LLLT (810 nm, 1 and 3 J) at the sites of the injections, or with intramuscular sodium diclofenac. Regarding biochemical analyses, LLLT significantly decreased (p < 0.05) COX-2, TNF-α, MMP-3, MMP-9, and MMP-13 gene expression, as well as prostaglandin E(2) (PGE(2) ) production when compared to collagenase group. Interestingly, diclofenac treatment only decreased PGE(2) levels. Biomechanical properties were preserved in the laser-treated groups when compared to collagenase and diclofenac groups. We conclude that LLLT was able to reduce tendon inflammation and to preserve tendon resistance and elasticity.