Photodynamic Therapy With a New Photosensitizer, Fullerodendrimer, Induced Apotosis in Human Umbilical Endothelial Cells

Abstract

Abstract: : Purpose: Fullerodendrimers ,consisting of fullerens(C₆₀) and dendrimers,have been reported to produce singlet oxygen effectively with light irradiation and expected to be a new photosensitizer for photodynamic therapy(PDT). Apotosis plays an important role in evaluating the photodynamic effect. In the present study we investigated whether or not PDT with fullerodendrimers induced apotosis in human umbilical endothelial cells(HUVECs). Methods: We synthesized the fullerodendrimer,C₆₀(G1.5–COOK), by the use of a Diels–Alder reaction of C₆₀ with anthryl dendron. The fullerodendrimer has an excitation wavelength at 685nm. A semiconductor laser(685nm) was used as the light source for exciting the fullerodendrimer. HUVECs (1.0×10⁴cells/ml)were plated onto 3 chamber slide plates. After 24h incubation, the fullerodendrimer with different concentrations (0µg/ml, 1µg/ml,10µg/ml)were added to the 9 wells, then all wells were irradiated with 30J/cm² using the semiconductor laser. After 48h incubation,TUNEL assay was performed for the evaluation of apotosis. Results: TUNEL–positive nuclei were detected by fluorescent–microscopic analysis. The laser irradiation with 30J/cm² and the fullerodendrimer at 1µg/ml,10µg/ml induced apotosis 18.9%,49.1% of HUVECs respectively. In contrast,only 3.8% of TUNEL–positive cells were observed in control. Conclusions: The present study indicates that the combination of the fullerodendrimer and the laser irradiation induces apotosis of HUVECs in vitro. Fullerodendrimers are expected to be a new photosensitizer for PDT.

Keywords: apoptosis/cell death • drug toxicity/drug effects • laser