Articles

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 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 experiment 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 /cms² (placebo), 3 J/cm², 7.5 J/cm², and 15 J/cm², 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/cm² group, at 2.7 (95% CI: 2.5-2.9) x 106, versus 7.9 (95% CI: 6.7-9.7) x 106 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 cell migration measured. Under these conditions and at 2.5 mW, 7.5 J/cm² was more effective than 3 J/cm² and 15 J/cm².

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