Transcutaneous systemic photobiomodulation reduced lung inflammation in experimental model of asthma by altering the mast cell degranulation and interleukin 10 level.

Asthma is a chronic inflammatory disease characterized by recurrent and reversible episodes of wheezing, dyspnea, chest stiffness, and cough. Its treatment includes several drugs, high cost, and considerable side effects. Photobiomodulation (PBM) emerges as an alternative treatment, showing good results, and it can be applied locally or systemically. Here, we aim to evaluate the effect of transcutaneous systemic photobiomodulation (TSPBM) by red diode light. Therefore, adult rats were sensitized and challenged with ovalbumin (OVA) plus alum for induction of asthma and irradiated or not with TSPBM in the caudal vein (wavelength 660 ± 10 nm; total radiant emission 15 J; area 2.8 cm2; energy density 5.35 J/cm2; irradiance 33.3 mW/cm2; exposure time 150 s). Our investigations prioritized the cell migration into the alveolar space and lung, tracheal responsiveness, release and gene expression of cytokines, mast cell degranulation, and anaphylactic antibodies. Our results showed that TSPBM reduced the cell migration and mast cell degranulation without altering the tracheal responsiveness and ovalbumin antibody titers. Indeed, TSPBM increased the levels of interleukin 10 (IL-10) in the BAL fluid without altering the gene expression of cytokines in the lung tissue. Thus, this study showed that transcutaneous systemic irradiation reduced lung inflammation by altering mast cells degranulation and IL-10 level. Considering that this study is a pioneer in the used of light by the systemic route to treat asthma, the data are interesting and instigate future investigations, mainly in relation to the mechanisms involved and in dosimetry.