Effects of Methylene Blue Mediated Photodynamic Therapy on SolidEhrlich Tumor and Second Ehrlich Tumor Implant in Mice

Abstract

<span style=font-family: times= new= roman,serif;mso-fareast-font-family:times= roman;color:black=>1. Abstract PhotoDynamic Therapy (PDT) uses interaction of light, photosensitizing agent and production of reactive oxygen species, leading to cell death. Methylene Blue (MB) is sued for PDT due to its photochemical properties. Here we investigated the effects of Methylene Blue Mediated Photodynamic Therapy ( MB-PDT) on the solidEhrlich tumor and second Ehrlich tumor implant in mice. For MB-PDT, MB at 1%and diode laser were used. Swiss male mice received dorsal inoculation of Ehrlichtumor cells and, 9 days after, mice were separated into 3 groups: MB-PDT ( Group1 ) surgically removed (Group 2 ), or untreated ( Group 3 ). One day after treatment,all groups received a second Ehrlich tumor implant on the left footpad, measured for17 days. Spleen, lymph nodes and tumor mass were weighed upon necropsy andprocessed for histopathology. Group 1 Ehrlich tumors showed significant sizereduction after MB-PDT. Morphometry of second Ehrlich tumor in Group 1 miceshowed significantly lower volume fraction of tumor cells, higher inflammatoryinfiltrate and necrosis. Relative spleen weight was higher in Group 1 mice, withwhite pulp hyperplasia. Per these results, MB-PDT reduced primary Ehrlich tumorgrowth and impacted the growth of a second tumor. These results point towardspossible biotechnological applications of MB-PDT. 2. Keywords: Photodynamic Therapy, Methylene Blue, Ehrlich Tumor, CancerTreatment.