Photodynamic effect on mouse urinary bladder cancer with the combination of pheophorbide a and Nd:YAG laser

Abstract

To develop a new therapeutic modality for urinary bladder cancer, we tested the photodynamic effect of a combination of pheophorbide a and Nd: YAG laser, with in vivo and in vitro studies, using transplantable mouse urinary bladder cancer MBT-2. In the in vivo study, a large necrotic area was observed macroscopically and microscopically after treatment. The in vitro studies revealed that this tumor killing effect was mainly photodynamic and not solely thermal. The intensity of this photodynamic effect was dependent on several factors, including concentration of pheophorbide a, time of contact with pheophorbide a and amount of laser energy. Pheophorbide a alone seemed to have no tumorcidal effect. These results show that the combination of pheophorbide a and Nd: YAG laser had definit antitumor effects against mouse urinary bladder cancer. These effects seem to be mainly derived from photodynamic reaction.