Spectral response for laser enhancement in hepatic regeneration for hepatectomized rats

Background and Objectives: The low intensity laser therapy (LILT) has been widely used in all medical fields due to its therapeutic effects in reparative process, pain relief, and biostimulation. Even though there is a therapeutic window of wavelengths for clinical application, little has been done concerning the frequency spectrum response to biological effects. In this work, we investigate the dependence of different wavelengths irradiation in the enhancement of the tissue regeneration after partial hepatectomy in Wistar rats. Study Design/Materials and Methods: The proliferating cell nuclear antigen (PCNA) labeling index and the respiratory control (oxygen consumption in extracted mitochondria) were the tests used to evaluate the liver regeneration after laser irradiation with different wavelengths. Results and Conclusions: The results show a correlated spectral response that can be explained based on the combined effect of light penetration on biological tissues and the biomolecular excitation efficiency for each wavelength used. (C) 2003 Wiley-Liss, Inc.