Toxicity to the normal hemocytes by ALA-PDT for the ex vivo purging of hematopoietic stem cell grafts / 西安交通大学学报·英文版

ABSTRACT

Objective: To study the toxic effects of 5-amionlevulinic acid-based photodynamic therapy (ALA-PDT) on human peripheral blood mononuclear cells (PBMCs), cord blood mononuclear cells (CBMCs) and peripheral blood stem cells (PBSCs), and furthermore, to understand the possible causes of this response. Methods: We used MTT assay to detect the survival rate of PBMCs, CBMCs and PBSCs after treated by ALA-PDT under the optimum experiment conditions with U937 as control; Annexin V-FITC/PI was used to detect the pattern of cell death induced by ALA-PDT. By using flow cytometry, we detected intracellular PpIX fluorescence intensity. Results: After ALA-PDT treatment the survival rate of PBMCS had no significant change; however in PBSCS and CBMCs, the survival rate reduced to 70%, and the survival rate of leukemia cell U937 was the lowest, about 30%. After incubation with ALA, except for PBMCs, intracellular PpIX fluorescence intensity of the other two kinds of normal haemocytes and U937 increased obviously. These results combined with the flow cytometry suggested that the main pattern of cell death here was apoptosis. Conclusion: Under the optimum experiment conditions, ALA-PDT has a slight effect on normal haemocytes but excellent depletions of leukemia cells. Therefore, it can effectively purify autologous bone marrow or stem cell grafts.