Comparison of topical low-intensity photodynamic therapy using 5-aminolevulinic acid and methylene blue in wound healing by multiphoton microscopy in-vivo
Wound healing is a complex physiological and dynamic process that occurs to the components of the skin at the cellular and molecular levels. Most researches are directed to promote the wound healing process, one of the method is low-intensity photodynamic therapy. Low-intensity photodynamic therapy (LIPDT) is a promising approach provided good results in the wound healing process, acting in several steps and accelerating tissue repair. Low-intensity photodynamic therapy is based on the application of a photosensitive compound - photosensitizer, light with the appropriate wavelength, and oxygen. The multiphoton microscopy (MPM) is a useful tool for the non-invasive investigation of morphological and biophysical characteristics of human skin in vivo, which evaluates the regeneration of collagen and change in cellular metabolic rate during wound healing, with second harmonic generation (SHG) and autofluorescence (AF).
In this study, a comparison between topical photodynamic therapy with two different photosensitizers, 5-aminolevulinic acid and methylene blue, and two laser doses 1J/cm2 and 4 J/cm2 was studied by multiphoton microscopy in vivo. Also, as a specific parameter for wound healing and its course the second-harmonic generation-to autofluorescence aging index of dermis (SAAID) was used, which defines as follows: SAAID = (SHG-AF)/(SHG+AF).
The research was carried out with the support of a grant under the Decree of the Government of the Russian Federation No. 220 of 09 April 2010 (Agreement No. 075-15-2021-615 of 04 June 2021).
Tomsk State University
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