Photobiomodulation therapy improves both inflammatory and fibrotic parameters in experimental model of lung fibrosis in mice

Lasers Med Sci. 2017 Nov;32(8):1825-1834. doi: 10.1007/s10103-017-2281-z. Epub 2017 Jul 16.


Lung fibrosis (LF) is a chronic and progressive lung disease characterized by pulmonary parenchyma progressive lesion, inflammatory infiltration, and interstitial fibrosis. It is developed by excessive collagen deposition and other cellular matrix components, resulting in severe changes in the alveolar architecture. Considering the absence of effective treatment, the aim of this study was to investigate the effect of photobiomodulation therapy (PBMT) on the development of PF. For this purpose, we used C57BL6 mice subjected to induction of LF by bleomycin administration (1.5 U/kg) by orotracheal route and, after 14 days of the induction, mice were treated with PBMT applied to the thorax 1×/day for 8 days (wavelength 660 ± 20 nm, power 100 mW, radiant exposure 5 J/cm2, irradiance 33.3 mW/cm2, spot size 2.8cm2, total energy 15 J, time of irradiation: 150 s) and inflammatory and fibrotic parameters were evaluated with or without PBMT. Our results showed that PBMT significantly reduced the number of inflammatory cells in the alveolar space, collagen production, interstitial thickening, and static and dynamic pulmonary elastance. In addition, we observed reduced levels of IL-6 e CXCL1/KC released by pneumocytes in culture as well as reduced level of CXCL1/KC released by fibroblasts in culture. We can conclude that the PBMT improves both inflammatory and fibrotic parameters showing a promising therapy which is economical and has no side effects.

Keywords: Collagen production; Cytokines; Lung elastance; Lung fibrosis; Mice; Photobiomodulation therapy (PBMT).

MeSH terms

  • Alveolar Epithelial Cells / metabolism
  • Alveolar Epithelial Cells / radiation effects
  • Animals
  • Bleomycin
  • Bronchoalveolar Lavage
  • Chemokine CXCL1 / metabolism
  • Collagen / biosynthesis
  • Disease Models, Animal
  • Fibroblasts / metabolism
  • Fibroblasts / radiation effects
  • Inflammation / complications
  • Inflammation / pathology*
  • Interferon-gamma / metabolism
  • Interleukin-6 / metabolism
  • Low-Level Light Therapy / methods*
  • Lung / pathology
  • Lung / radiation effects
  • Male
  • Mice, Inbred C57BL
  • Pulmonary Fibrosis / radiotherapy*


  • Chemokine CXCL1
  • Cxcl1 protein, mouse
  • Interleukin-6
  • Bleomycin
  • Interferon-gamma
  • Collagen