Investigating the wound healing potential of low-power 661 nm laser light in a pigmented hairless murine model.

Abstract

Photobiomodulation (PBM) has emerged as a promising method for enhancing wound healing. However, a standardized therapeutic protocol has not yet been established. This study aimed to determine the optimal irradiation parameters for wound healing in pigmented hairless mice (SKH-hr2). Mice were irradiated daily with energy doses of 2 or 4 J/cm², achieved with different power densities in each group: 20, 50, or 100 mW/cm². Various methods were used to evaluate the therapeutic efficacy, including histopathological analysis, clinical observation, photo-documentation, assessment of biophysical skin parameters, and Fourier Transform infrared (FT-IR) spectroscopy. The results indicated that the most favorable outcomes regarding wound healing acceleration and inflammation reduction were achieved with an irradiation setting of 50 mW/cm² and 2 J/cm². However, the group subjected to prolonged irradiation times with a power density of 20 mW/cm² and energy of 4 J/cm² exhibited subcutaneous bleeding. The FT-IR spectral absorption bands of amide groups provided important molecular-level information about the secondary structure of collagen, particularly in relation to skin regeneration and the response to applied energy, in agreement with histological data. This study highlights the critical need for further investigation into the parameters of photobiomodulation to ensure its effective application to the different skin phototypes and to mitigate potential adverse effects arising from incorrect usage.