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) = 1^th biopsy; intermediate (9 weeks of evolution) = 2^nd biopsy; final (21 weeks of evolution) = 3^th biopsy. Treated (n = 21, inoculated and irradiated): early (13 weeks of evolution, 4 weeks after first irradiation) = 4^th biopsy, intermediate (17 weeks of evolution, 8 weeks after first irradiation) = 5^th biopsy, final (21 weeks of evolution, 12 weeks after first irradiation) = 6^th 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.

Keywords
Laser therapy; Low-power laser; Sporothrix schenckii; Sporotrichosis; Photobiomodulation