Beneficial effects of infrared light-emitting diode in corticosteroid-resistant asthma.

Corticosteroid-resistant asthma (CRA) is a severe form of disease and clinically important, since patients do not respond to mainstay corticosteroid therapies. Thus, new therapies are needed. However, a big limiting factor in the understanding of CRA is the existence of different immunological and inflammatory phenotypes, a fact that makes it difficult to reproduce experimentally. Photobiomodulation (PBM) emerges as an alternative therapy based on earlier studies. This study aims to evaluate the effect of PBM using infrared light-emitting diode (ILED) on the development of corticosteroid-resistant asthma. Therefore, groups of rats were sensitized and challenged with ovalbumin plus Freund's adjuvant for the induction of CRA, and treated or not with ILED directly in the respiratory tract on the skin (wavelength 810 nm; power 100 mW; density energy 5 J/cm; total energy 15 J; time 150 s). Our experimental model was capable to induce neutrophilic asthma. Besides that, the corticosteroid treatment did not reverse the lung cell migration as well as the levels of leukotriene B4, and interleukins 17 and 6. The treatment with ILED reduced the lung cell migration; myeloperoxidase activity; mast cell degranulation; and the levels of leukotriene B4, thromboxane B2, prostaglandin E2, tumoral necrosis factor alpha, and interleukins 17 and 6. Still, ILED increased the level of interleukin 10. In conclusion, we showed promisor effects of ILED when irradiated directly in the respiratory tract as adjuvant treatment of corticosteroid-resistant asthma.

Effects of formaldehyde exposure on the development of pulmonary fibrosis induced by bleomycin in mice.

Environmental and Occupational pollution has been extensively studied because of its serious implications on the human health. Formaldehyde (FA) is a pollutant widely employed in several industries and also in anatomy, pathology and histology laboratories. Studies have shown the correlation between FA exposure and development or worsening of asthma. However, the effect of FA exposure on the pulmonary fibrosis (PF) is unknown. PF is a progressive and chronic lung disease with high incidence and considerable morbidity and mortality. Few studies have shown a worsening of PF after pollutants exposure such as ozone and nitrogen dioxide. Therefore, our objective was to assess the effects of FA on the PF. Male mice C57BL6 were treated or not with bleomycin (1,5 U/kg) and exposed or not to FA inhalation (0.92 mg/m3, 1 h/day, 5 days/week during 2 weeks). Non-manipulated mice were used as control. Our data showed that FA exposure in fibrotic mice increased the number of granulocytes in the bronchoalveolar lavage followed by elevated levels of interleukin 1 beta and interleukin 17. In addition, FA exposure in fibrotic mice enhanced the gene expression of C-X-C motif chemokine ligand 1 (CXCL1) and tumor necrosis factor alpha (TNF-α) in the lung. We also showed an increase in the collagen production, while lung elastance was reduced. No differences were found in the mucus production, oedema and interstitial thickening in the lung tissue of fibrotic mice after FA exposure. In conclusion our study showed that FA exposure aggravates the lung neutrophils influx and collagen production, but did not alter the lung elastance, mucus production, oedema and interstitial tickening. This work contributes to understand the effects of pollution in the development of PF.

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

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.

Low Level Laser Therapy Reduces the Development of Lung Inflammation Induced by Formaldehyde Exposure.

Lung diseases constitute an important public health problem and its growing level of concern has led to efforts for the development of new therapies, particularly for the control of lung inflammation. Low Level Laser Therapy (LLLT) has been highlighted as a non-invasive therapy with few side effects, but its mechanisms need to be better understood and explored. Considering that pollution causes several harmful effects on human health, including lung inflammation, in this study, we have used formaldehyde (FA), an environmental and occupational pollutant, for the induction of neutrophilic lung inflammation. Our objective was to investigate the local and systemic effects of LLLT after FA exposure. Male Wistar rats were exposed to FA (1%) or vehicle (distillated water) during 3 consecutive days and treated or not with LLLT (1 and 5 hours after each FA exposure). Non-manipulated rats were used as control. 24 h after the last FA exposure, we analyzed the local and systemic effects of LLLT. The treatment with LLLT reduced the development of neutrophilic lung inflammation induced by FA, as observed by the reduced number of leukocytes, mast cells degranulated, and a decreased myeloperoxidase activity in the lung. Moreover, LLLT also reduced the microvascular lung permeability in the parenchyma and the intrapulmonary bronchi. Alterations on the profile of inflammatory cytokines were evidenced by the reduced levels of IL-6 and TNF-α and the elevated levels of IL-10 in the lung. Together, our results showed that LLLT abolishes FA-induced neutrophilic lung inflammation by a reduction of the inflammatory cytokines and mast cell degranulation. This study may provide important information about the mechanisms of LLLT in lung inflammation induced by a pollutant.