Selective necrosis in dimethylhydrazine-induced rat colon tumors using phthalocyanine photodynamic therapy

摘要: Abstract Photodynamic therapy is a relatively new method for the local destruction of tumors based on administration photosensitizing agent that retained in and then activated to produce cytotoxic agents following irradiation with light. The selective retention photosensitizers by dimethylhydrazine-induced colonic over adjacent normal tissue small (2:1, tumor normal), making possibility producing necrosis total sparing difficult. Colonic cancers colon were treated same light doses from an argon-pumped dye laser 48 h after intravenous injection 0.5 or 5 mg/kg photosensitizer, aluminum-sulfonated phthalocyanine. There was little difference between amount if injected dose photosensitizer mg/kg. However, at lower mg/g, up 2 mm could be produced withing damaging colon. In vivo fluoresecence measurements showed photodegraded during irradiation. This confirmed vitro fluorescence scans irradiation; lowest point It postulated low dosage, can occur because before threshold photodynamic reached, whereas containing twice as much achieved produced.