Photodynamic therapy with di-L-arginine protoporphyrinate on WiDr human colon adenocarcinoma xenografts in athvmic nude mice

摘要

The fluorescence kinetics of a new photosensitizer for photodynamic therapy, di-L-arginine protoporphyrinate (PP(Arg)_2), was studied in the skin of healthy mice. Furthermore, induction of necrosis in WiDr human colon adenocarcinoma xenografts in athymic nude mice was studied after photodynamic therapy (PDT) with PP(Arg)_2. After intravenous administration of PP(Arg)_2 maximal fluorescence was reached after 72 h in normal mouse skin. Complete elimination of the drug from the mouse skin was not found even after 32 days. Exposure of WiDr tumours in mice to red light (λ = 632 nm, fluence 150J/cm~2, fluence rate 250mW/cm~2) 24 and 72h after intravenous administration of 10mg/kg of PP(Arg)_2 caused extensive tumour necrosis. Epidermal damage and infiltration of inflammatory cells was seen 24 h after light exposure but not after 72 h.