Cytotoxicity of PP(Arg)2- and Hp(Arg)2-mediated photodynamic therapy and early stage of apoptosis induction in prostate carcinoma in vitro

Porphyrin photosensitizers tend to localize in mitochondria. The depolarization of mitochondrial membrane is one of the early stages of apoptosis and Laser Scanning Fluorescence Microscopy allows to determine changes in transmembrane mitochondrial potential under influence of PDT depending on the kind of photosensitizer (PP(Arg)2, Hp(Arg)2), the energy dose (5, 10, 30 and 50 J/cm2) and time periods (24 and 48 hours after irradiation) in the LNCaP (lymphonodal metastasis of prostate carcinoma, the androgen dependent cell line). Cyototoxicity induced by PP(Arg)2- and Hp(Arg)2-based PDT depending on energy dose and time after irradiation in prostate carcinoma is determined with MTT. Generally, it was shown that lower energy doses induce greater changes in transmembrane mitochondrial potential. Hp(Arg)2-based PDT was more effective causing greater mitochondrial membrane depolarization and cell viability decrease in comparison to PP(Arg)2-mediated PDT (in the case of maximal nontoxic photosensitizer doses used).