Analysis of laser therapy effects in sporothrix schenckii inactivation in vivo

Abstract

Introduction: Sporotrichosis is a common disease in tropical regions, caused by the fungus Sporothrix schenckii, affecting mainly rural workers and in direct contact with animals. Although treatment by indiscriminate use of oral antifungal drugs gives rise resistant isolates, leading to therapeutic failures and no remission of the disease. To evaluate the effectiveness of red low-power laser photobiomodulation in inactivation of S. schenckii infection induced in rodents. Methods: Subcutaneously inoculation (2x103 S. schenckii/ml, 0.2 ml suspension) in the left footpad, in 27 mice divided into: control (n = 6, inoculated, without irradiation): early stage (not inoculated) = 1th biopsy; intermediate (9 weeks of evolution) = 2nd biopsy; final (21 weeks of evolution) = 3th biopsy. Treated (n = 21, inoculated and irradiated): early (13 weeks of evolution, 4 weeks after first irradiation) = 4th biopsy, intermediate (17 weeks of evolution, 8 weeks after first irradiation) = 5th biopsy, final (21 weeks of evolution, 12 weeks after first irradiation) = 6th biopsy. Serial irradiation with biopsies occurred every 30 days during each month, for three months. At the end of testing, the mice were euthanized, and histological analyzes of biopsies were performed. Results: Each laser treatment session showed an inactivation of S. schenckii in treated animals compared to controls, with a regression of pseudoepitheliomatous hyperplasia, chronic inflammation, neutrophils, granulomas, giant mononuclear cells and steroid corpuscles. Conclusion: The laser photobiomodulation was effective on S. schenckii inactivation, appearing to be an interesting therapeutic option in infections caused by this organism. © 2018, Brazilian Society of Biomedical Engineering. All rights reserved.