Spontaneous effects of low-level laser therapy (650 nm) in acute inflammatory mouse pleurisy induced by carrageenan

Photomed Laser Surg. 2005 Aug;23(4):377-81. doi: 10.1089/pho.2005.23.377.


Objective: Our aim was to investigate the effect of low-level laser therapy (LLLT), 650-nm wavelength, on acute inflammatory pleurisy.

Background data: 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).

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrageenan / adverse effects
  • Chemotaxis, Leukocyte / radiation effects*
  • Irritants / adverse effects
  • Low-Level Light Therapy*
  • Male
  • Mice
  • Pleurisy / chemically induced
  • Pleurisy / immunology*
  • Pleurisy / therapy*


  • Irritants
  • Carrageenan