<title>PDT mechanism of phthalocyanines by ultrastructural cytochemical cerium deposition localization EDX technique and apoptosis detection</title>

Abstract

Both the chemical mechanisms of photodynamic therapy (PDT) with new photosensitizer phthalocyanine (PC) and the relationship between the chemical mechanisms and the pathologic mechanism in PDT with PC (PC PDT) are not exactly clear. In this study, the mechanisms of PC-PDT in vitro and in vivo were aimed with research methods of ultrastructural cytochemical cerium deposition locations, EDX technique and apoptosis detection. Three kinds of PCs, disulfonated chloroaluminium PC, AlS3PC and disulfonated zinc PC, were adopted in the experiments. The result revealed: (1) There are a direct proportion between the amount of the 1O2 enhancer and the amount of cerium deposition and an inverse ratio between the amount of the 1O2 quencher and the deposition. So the dominant mechanism of PC-PDT is 1O2; (2) The ultrastructural sties of most obvious pathologic damage ar the sites of richness in PC and the sites of richness in cerium deposition; the mitochondria is one of the most important PDT targets in tumor cells, and secondly other cytomembrane structures are also important sites injured by PC-PDT; both the PDT damages to tumor cells and that to microvasculature are the significant pathologic mechanisms for killing tumor cells in vivo; (3) Apoptosis is an event in the tumor killing process of PC-PDT.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.