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

• Published in: Journal of photochemistry and photobiology. B, Biology Biology, 2017-12, Vol.177, p.69-75
• Main Authors: Petrellis, Maria Carla, Frigo, Lúcio, Marcos, Rodrigo Labat, Pallotta, Rodney Capp, de Carvalho, Maria Helena Catelli, Muscará, Marcelo Nicolás, Maria, Durvanei Augusto, Lopes-Martins, Rodrigo Álvaro Brandão
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Biomarkers, Tumor - metabolism; Body weight; Breast Neoplasms - radiotherapy; Cancer; Cell Line, Tumor; Cyclooxygenase 1 - genetics; Cyclooxygenase 1 - metabolism; Cyclooxygenase 2 - genetics; Cyclooxygenase 2 - metabolism; Cyclooxygenase-1; Cyclooxygenase-2; Cytokines; Cytokines - analysis; Cytotoxicity; Energy; Enzymatic activity; Enzyme-Linked Immunosorbent Assay; Female; Gene expression; Gene Expression - radiation effects; Inflammation; Inflammation Mediators - metabolism; Interleukin 10; Interleukin 6; Lasers; Lasers, Solid-State - therapeutic use; Low level laser therapy; Low-Level Light Therapy; Markers; Membrane potential; Mitochondria; Nitric Oxide Synthase Type II - genetics; Nitric Oxide Synthase Type II - metabolism; Nitric Oxide Synthase Type III - genetics; Nitric Oxide Synthase Type III - metabolism; Nitric-oxide synthase; Oxidative stress; Phosphates; Photodynamic therapy; Polymerase chain reaction; Rats; Rats, Wistar; Reactive oxygen species; Reactive Oxygen Species - metabolism; Rodents; Solid tumors; Statistical analysis; Studies; Transduction; Tumor cells; Tumor necrosis factor-α; Tumors; Walker Tumor 256
• ISSN: 1011-1344; 1873-2682
• DOI: 10.1016/j.jphotobiol.2017.09.011

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. 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-1β, 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. We found that the 1Joule (J) treated group promoted a significant increase in the levels of different inflammatory markers IL-1β, the gene expression of COX-2, iNOS, which was statistically different (p