Anti‐Inflammatory effects of low‐level laser therapy (660 nm) in the early phase in carrageenan‐induced pleurisy in rat

Abstract

Background and Objective: In the classic model of pleurisy there is little evidence about the anti-inflammatory effects of low-level laser therapy (LLLT) as well the dosage characteristics, such as wavelength, total energy, number and pattern of treatment. In this study we investigated the potential effects of LLLT on modulating the pro-inflammatory and anti-inflammatory mediators of acute inflammation in a rat pleurisy model. Study Design/Materials and Methods: A sample of 48 female Wistar rats were divided into control and experiential groups. An inflammation was induced by carrageenan (0.2 ml) injected into the pleural cavity. At 1, 2, and 3 hours after induction a continuous wave (20 mW) diode laser of the InGaAlP (660 nm) type was used in the four laser groups with different doses and treatment patterns. One group received a single dose of 2.1 J and the other three groups received a total energy of 0.9, 2.1, and 4.2 J. Four hours later the exudate volume, total and differential leukocytes, protein concentration, NO, IL-6, IL-10, TNF-a, and MCP-1 were measured from the aspirated liquid. Results: All the treatment patterns and quantity of energy studied show significant reduction of the exudate volume (P<0.05). Using energy of 0.9 J only NO, IL-6, MCP-1 and IL-10 are significantly reduced (P<0.05). On the other hand, higher energies (2.1 and 4.2 J) significantly reduce all variables independently of the treatment pattern. The neutrophil migration has a straight correlation with the TNF-a (r ¼ 0.551) and NO (r ¼ 0.549) concentration. Conclusions: LLLT-660 nm induced an anti-inflammatory effect characterized by inhibition of either total or differential leukocyte influx, exudation, total protein, NO, IL-6, MCP-1, IL-10, and TNF-a, in a dose-dependent manner. Under these conditions, laser treatment with 2.1 J was more effective than 0.9 and 4.2 J. Lasers Surg.

Low-level laser in the treatment of carpal tunnel syndrome: clinical, electrophysiological, and ultrasonographical evaluation

“…Studies on the stimulation of nerve regeneration and on nerve conduction by LLLT support the concept that this treatment might facilitate recovery of nerve and stimulate the regeneration of peripheral nerves [15,16]. LLLT has also shown to have a role in pain and inflammatory process [17][18][19]. On the other hand, a placebo-controlled, randomised, and doubleblind study by Irvine et al has not been able to demonstrate any significant or convincing clinically relevant effects over placebo in the treatment of CTS [20].…”

Biological Function of Low Reactive Level Laser Therapy (LLLT)

“…In a rat model of carrageenan-induced pleuritis, a 660-nm indium-gallium-aluminum-phosphate laser suppressed the production of inflammatory cytokines and the migration of inflammatory cells [9]. A group of researchers led by Albertini are actively pursuing research on LLLT's antiinflammatory effects .…”

Efeitos local e sistêmico do laser de baixa potência no limiar de dor por pressão em indivíduos saudáveis

“…O LBP vem sendo usado com o objetivo de promover efeitos analgésicos [4][5][6][7] , modulação da inflamação [8][9][10][11][12][13][14] , efeitos cicatriciais [15][16][17] e vasodilatadores locais 19 , sem os riscos de produção de calor e dano ao tecido irradiado 7,18,19 . A ação analgésica da laserterapia pode ser explicada a partir de algumas hipóteses: modulação dos processos inflamató-rios 3,9,20 , alteração da excitação e condução nervosa dos neurônios periféricos 21,22 , liberação de opioides endógenos 23,24 e aumento na síntese de serotonina 4,25 .…”