M. A. Calin, S. Botea, In vivo comparison of simple and double-fractionated low-level laser irradiation schemes on the healing of rat skin lesions, Photomedicine and Laser Surgery, 28/2 (2010) 245-250.

Title: In vivo comparison of simple and double-fractionated low-level laser irradiation schemes on the healing of rat skin lesions

Abstract: Objective: To compare the efficacy of a simple irradiation scheme with that of a double-fractionated irradiation scheme on the healing of rat skin lesions using in vivo monitoring of tissue diffuse reflectance. Background Data: Low-level laser therapy (LLLT) is used in medicine for treating a wide range of pathological conditions. The practical benefits of laser treatment of acute and chronic conditions were obtained, using a single session of irradiation per day. Materials and Methods: Thirty Wistar rats were divided into three experimental groups (controls, simple laser irradiation scheme, and double-fractionated laser irradiation scheme). A skin lesion was created on the calf of the right hind leg of all rats. The laser irradiation parameters were λ = 635 nm and power = 15 mW. The exposure time was 600 s for the simple laser irradiation scheme and 300 s × 2 for the double-fractionated laser irradiation scheme on 3 consecutive days. The optical properties of tissue were studied by processing and analyzing the diffuse reflectance spectra of injured skin, acquired before and after each laser irradiation. Results: The results demonstrate that, using a simple laser irradiation scheme (single daily irradiation session: t_exp1=600s, power = 15 mW, λ = 635 nm), healing of the skin lesion began after 3 consecutive treatment days. The application of the double-fractionated laser irradiation scheme (2 daily irradiation sessions: t_exp2 = t_exp1/2 = 300 s, power = 15 mW and λ = 635 nm) led to a reduction in treatment time to 2 days. Conclusion: In conclusion, a double-fractionated irradiation scheme is more efficient than simple irradiation scheme for LLLT in rat skin lesions

Key words:laser, fractioned irradiation, skin lesions, diffuse reflectance spectroscopy