Photobiomodulation in Sciatic Nerve Crush Injuries in Rodents: A Systematic Review of the Literature and Perspectives for Clinical Treatment

Abstract Introduction: The aim of the study was to perform a literature review to analyze the effect of photobiomodulation in experimental studies on peripheral nerve regeneration after sciatic nerve crush injury in rodents.Methods: A bibliographic search was performed in the electronic databases, including MEDLINE (PubMed), SCOPUS, and SciELO, from ۲۰۰۸ to ۲۰۱۸.Results: A total of ۱۹۱۲ articles were identified in the search, and only ۱۹ fulfilled all the inclusion criteria. Along with the parameters most found in the manuscripts, the most used wavelengths were ۶۶۰ nm and ۸۳۰ nm, power of ۳۰ and ۴۰ mW, and energy density of ۴ and ۱۰ J/cm۲. For total energy throughout the intervention period, the lowest energy found with positive effects was ۰.۷۰ J, and the highest ۱.۱۴۱ J. Seventeen studies reported positive effects on nerve regeneration. The variables selected to analyze the effect were: Sciatic Functional Index (SFI), Static Sciatic Index (SSI), morphometric, morphological, histological, zymographic, electrophysiological, resistance mechanics and range of motion (ROM). The variety of parameters used in the studies demonstrated that there is yet no pre-determined protocol for treating peripheral nerve regeneration. Only two studies by different authors used the same power, energy density, beam area, and power density.Conclusion: It was concluded that the therapeutic window of the photobiomodulation presents a high variability of parameters with the wavelength (۶۳۲.۸ to ۹۴۰ nm), power (۵ to ۱۷۰ mW) and energy density (۳ to ۲۸۰ J /cm۲), promoting nerve regeneration through the expression of cytokines and growth factors that aid in modulating the inflammatory process, improving morphological aspects, restoring the functionality to the animals in a brief period.Keywords: Phototherapy; Nerve regeneration; Sciatic nerve; Experimental studies; Injury; Lasers and light sources. Keywords: Phototherapy Nerve Regeneration Sciatic nerve Experimental studies Injury Lasers and light sources.