Spontaneous effects of low-level laser therapy (650 nm) in acute inflammatory mouse pleurisy induced by carrageenan.
OBJECTIVE
Our aim was to investigate the effect of low-level laser therapy (LLLT), 650-nm wavelength, on acute inflammatory pleurisy.


BACKGROUND
There is only scattered evidence of anti-inflammatory effects from LLLT and dosage characteristics, and the effect on pleurisy inflammation has yet to be investigated.


METHODS
A classical experimental model of pleurisy was used in a sample of 40 Balb male mice, randomly divided into five groups. Inflammation was induced by carrageenan (0.5 mg/cavity) administered by intrathoracic injections. Four groups received the inflammatory agent, and one received injections of sterile saline solution. At 1, 2, and 3 h after injections, LLLT irradiation was performed, with the same power (2.5 mW), but different irradiation times. The energy densities at each of the three treatment sessions were 0 J/cm(2) (placebo), 3 J/cm(2), 7.5 J/cm(2), and 15 J/cm(2), respectively.


RESULTS
Total and differential cell analysis at 4 h after induction of pleurisy showed a significant reduction of inflammatory cell migration for all groups treated with active laser. However, at 4 h after injection, the most significant (p < 0.001) reduction of leukocyte cell migration was seen in the 7.5 J/cm(2) group, at 2.7 (95% CI: 2.5-2.9) x 10(6), versus 7.9 (95% CI: 6.7-9.1) x 10(6) in the placebo control group. The greatest reduction of inflammatory cells was registered for neutrophils.


CONCLUSIONS
LLLT administered at 1-3 h after the induction of inflammatory pleurisy significantly reduces the inflammatory cell migration measured. Under these conditions and at 2.5 mW, 7.5 J/cm(2) was more effective than 3 J/cm(2) and 15 J/cm(2).
Lopes-Martins
Rodrigo Alvaro Brandão
RA
Research Group of Laser and Inflammation, Instituto de Pesquisa & Desenvolvimento, Universidade do Valedo Paraíba, Urbanova, São José dos Campos, SP, Brazil. martins@icb.usp.br
Albertini
Regiane
R
Martins
Patrícia Sardinha Leonardo Lopes
PS
Bjordal
Jan Magnus
JM
Faria Neto
Hugo Caire Castro
HC
D000818:Animals; D002351:Carrageenan / Q000009:adverse effects; D002634:Chemotaxis, Leukocyte / Q000528:radiation effects*; D007509:Irritants / Q000009:adverse effects; D028022:Low-Level Light Therapy; D008297:Male; D051379:Mice; D010998:Pleurisy / Q000139:chemically induced / Q000276:immunology* / Q000628:therapy*
D007509:Irritants; D002351:Carrageenan