PERMEATION OF LYSOSOMAL MEMBRANES IN THE COURSE OF PHOTOSENSITIZATION WITH METHYLENE BLUE AND HEMATOPORPHYRIN: STUDY BY CELLULAR MICROSPECTROFLUOROMETRY

Abstract

Abstract— The photodynamically‐induced liberation of lysosomal enzymes using ß‐galactosidase as marker for the lysosomal enzymes has been studied by microspectrofluorometry on mouse L cells. Similar studies have been carried out using N‐acetyl‐ß‐D‐glucosaminidase as marker for the lysosomal enzymes of human fibroblasts. The high sensitivity of the fluorescence detection makes it possible to use 4‐methylumbelliferyl substrates for the enzymes contained in a single cell. Methylene blue and hematoporphyrin readily incorporate into both cells and upon excitation, sensitize lysosomal membrane damages, leading to enzyme release accompanying strong morphological changes.