Discrepancy between photodynamic injuries and pheophorbide A accumulation in digestive tissues

摘要

This report describes the discrepancy between pheophorbide A (PH-A) localization and photodynamically induced necrosis for the digestive tract. After an IV 9 mg/Kg$+$MIN@1$/ sensitization, the dye was caught by the whole digestive tract and its inherent vessels, as shown by fluorescence microscopy. The dye fluorescence disappeared within 24 h from the stomach and the jejunum. It remained high in the pancreas, the portal vein, the bile duct, the arteries and the duodenal mucosae. A light dose, 660 nm, 100 J/cm$+$MIN@2$/, 24 h after Ph-A sensitization, induced a necrosis of the duodenal mucosae. The pancreas and the hepatic pedicle were relatively unaffected by photodynamic therapy (PDT). The duodenal response to PDT results logically from its selective PH-A retention. But hepatic pedicule and pancreas immunities for PDT involve either protecting singlet oxygen scavengers or photosensitizer quenchers.