Evaluation of Low Intensity Laser Effects on the Thyroid Gland of Male Mice

Abstract

Objective: The purpose of this study was to assess whether there were alterations in the thyroid hormone plasma levels under infrared laser irradiation, in the thyroid gland region. Background Data: Studies have demonstrated that infrared laser can cause alterations in thyroid glands. Methods: Sixty-five albino male mice were used and assigned to five groups (n = 13), with differences in the times that they were sacrificed. Irradiation procedures consisted of an infrared diode laser emitting at 780 nm, at 4 J/cm² energy density, in contact mode, point manner. Blood was collected before irradiation (group 1), and then at 24 h (group 2), 48 h (group 3) and 72 h (group 4), and 1 week (group 5) after the third irradiation. The collected material was used for clinical analysis to evaluate the T₃ (triiodothyronine) and T₄ (thyroxin) hormones. Five animals were used for light microscopy analysis. Results: A statistically significant hormonal level alteration between the first day and 7 days after the last irradiation was found. Conclusions: It was concluded that low-level laser therapy (LLLT) of the thyroid gland may affect the level of thyroidal hormones.