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

Abstract

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.

Beneficial effects of Red Light-Emitting Diode treatment in experimental model of acute lung injury induced by sepsis

“…The investigators chose to study LED radiation in the visible (660 nm) regions of the red color spectrum, because in earlier studies, this spectrum has shown beneficial effects for the treatment of lung disease 21 , 22 . Be that as it may, this same visible region for laser has also demonstrated excellent effects 15 , 16 , 19 , 20 . We used the visible red color in our studies because several studies of the literature have shown that the wavelength of visible red is more effective to treat tissues and organs, which are deeply localized, as lungs.…”

“…Photobiomodulation has shown promissory effects in several lung diseases, including ALI 15 – 22 . By using lung inflammatory models, we have shown that treatments with low level laser therapy (LLLT) have reduced the development of neutrophilic lung inflammation that was induced by formaldehyde (FA), as observed by the reduced number of leukocytes, mast cell degranulation, and MPO activities, in the lung 16 , 17 .…”

“…Photobiomodulation is a treatment that is based on the effects of light on damage tissues, such as lasers, light-emitting diode (LED), among others. Photobiomodulation has been pointed out as an interesting tool for the treatment of lung diseases, as experimental studies have shown that a low level of laser therapy reduces the inflammation and oxidative stress in lung disorders 15 – 20 . However, the beneficial effect of LED in the lung diseases, such as experimental model of asthma 21 and lung fibrosis 22 has been shown by our group.…”

Immunomodulatory effects of two different physical therapy modalities in patients with chronic obstructive pulmonary disease

“…De-Silva et al 45 ) , also examined the effect of LLLT on acute lung inflammation induced by formaldehyde inhalation in rats. Infrared laser (660 nm), with power out of 30 mw was applied at the trachea (3 Points) and at each lung lobe (3 points for each lung).…”

“…The previous study concluded the anti-inflammatory effect of LLLT (increase in the level of IL-10) associated with a reduction in IL-6 as observed in the present study. The study of De-Silva et al 45 ) shed the light on the possible complex role of IL-6 in lung diseases associated with chronic inflammation.…”