Effect of Photodynamic Therapy on Proliferation and Apoptosis of 3T3 Fibroblasts and HeLa Cells

OBJECTIVE: The aim of the study was to test the effect of photodynamic therapy on fibroblast proliferation in vitro using protoporphyrin IX as a photosensitizer. BACKGROUND DATA: The abnormal proliferation of synovial tissue serves as a propagator of immune response and tissue damage in rheumatoid arthritis. Since the synovial fibroblasts mediate most relevant pathways of joint destruction, they constitute an important target for novel therapeutic approaches. Photodynamic therapy, which is the clinically applied treatment for various tumors, as well as for some non-oncologic diseases, is based on administration of an exogenous photosensitizer which is used to induce cell death of fibroblast cells. MATERIALS AND METHODS: The photosensitizing effects of protoporphyrin IX (PpIX) were studied in the 3T3 cell line that served as a model of fibroblasts and HeLa cells cultured in vitro. RESULTS: The number of fibroblasts and HeLa cells treated with photo-activated PpIX decreased significantly. The compound affects the viability of study cells, causing necrosis of 3T3 cells and apoptosis of HeLa cells. CONCLUSIONS: The light-activated protoporphyrin affected proliferation of both 3T3 and HeLa cells. No effects of the phototherapy were seen in the form of apoptosis of 3T3 cells, whereas the induction of cell death in HeLa cells was detected.