Potential anti-inflammatory effect of low-level laser therapy on the experimental reflux laryngitis: a preliminary study

Abstract

The most common cause of laryngitis is the laryngopharyngeal reflux disease. The symptoms of laryngitis can be hoarseness, globus, chronic cough, voice fatigue, throat pain, and dysphagia. Low-level laser therapy (LLLT) is beneficial to reduce the pain and inflammatory response without side effects. Therefore, LLLT may be a useful tool for the treatment of laryngitis. This study proposes to analyze the effect of laser therapy in a model of reflux-induced laryngitis. The animals were randomly put into three groups: control--non-intubated; nasogastric intubation--intubated; and nasogastric intubation with laser therapy-intubated treated with 105-J/cm(2) laser irradiation. For the induction of laryngitis, the animals were anesthetized and a nasogastric tube was inserted through the nasopharynx until it reached the stomach, for 1 week. Thereafter, measurement of myeloperoxidase activity and the histopathological procedures were performed. In conclusion, we observed in this study that 105-J/cm(2) infrared laser reduced the influx of neutrophils in rats, and it improved the reparative collagenization of the laryngeal tissues.

Effects of Different Protocols of Low-Level Laser Therapy on Collagen Deposition in Wound Healing

“…Low-level laser therapy provided a significant decrease in the severity of the inflammatory response in the late phases of wound healing independent of the protocol used. Supporting our findings, similar results have also been reported in the literature (15)(16)(17).…”

“…However, a possible role played by intracellular chromophores, such as porphyrins and cytochromes, which are capable of absorbing light energy and converting it into metabolic energy, has been suggested. Thus, LLLT would be able to improve scar repair by direct stimulation of fibroblastic metabolism, promoting an enhancement of the in intracellular levels of adenosine triphosphate and consequently increased protein synthesis, particularly collagen (16). In addition, LLLT promotes important changes in the chemical mediators directly involved in repair, such as reduction of cyclooxygenase-2 (COX-2) expression and consequently the severity of the inflammatory response and increased expression of VEGF, a crucial growth factor for formation of granulation tissue (15,21).…”

Low-level laser therapy/photobiomodulation in the management of side effects of chemoradiation therapy in head and neck cancer: part 2: proposed applications and treatment protocols

“…A study using an animal model of reflux laryngitis (a condition including hoarseness, voice fatigue, globus, chronic cough, throat pain, and dysphagia) suggested that the anti-inflammatory effects of PBM may play in the management of this condition [123]. …”

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“…[19]. Several RCTs reveal the effectiveness of LLLT in decreasing inflammation, tissue regeneration, and wound healing, especially in diabetic wounds and burn wounds [20][21][22]. Another RCT suggests using 810 nm IR light to accelerate functional recovery regarding the effects of this treatment on nerve injury after surgery [23].…”