Macromolecular synthesis and ultrastructural changes induced in human larynx carcinoma cells following photodynamic therapy in vitro

Human larynx carcinoma cells (HEp2) were sensitized with different concentrations of Hematoporphyrin and irradiated with a He-Ne laser at different fluences. The degree of PDT-effects were estimated by two parameters: a) macromolecular synthesis and b) observations using electron microscopy. All experiments were evaluated after 68 hr at 37 degrees C. The results showed that PDT exposure of HEp2 cells is characterized by: 1) inhibition of macromolecular synthesis and 2) different cellular and subcellular lesions. Summing up, these studies indicate the existence of a strong correlation between different PDT exposures and the degree of biochemical and ultrastructural changes in human larynx carcinoma cells in vitro.