Bioinhibition of human fibroblast cultures sensitized to Q-switch II dye and treated with the Nd: YAG laser: a new technique of photodynamic therapy with lasers.

Abstract

Kodak Q-switch II dye has recently proven to be an effective biostimulative agent on normal human fibroblast cultures. The potential for this dye as a new chemosensitizing agent for the treatment of connective tissue diseases and wound healing with the Nd:YAG laser was examined. Two normal fibroblast cell lines were first sensitized to a nontoxic dose of Q-switch II dye, then subjected to treatment with an Nd:YAG laser at 1,060 nm, with varying levels of energy and temperatures determined by a reproducible method of dosimetry. The results indicate that Q-switch II dye at nontoxic doses of 0.1 micrograms/ml enhances the cytotoxic effects of the Nd:YAG laser at temperatures as low as 36 degrees C. Furthermore, at physiological temperature ranges as low as 24 degrees C to 34 degrees C, cell duplication was inhibited, but cell viability was not affected. Similar results were not observed when fibroblast cultures were treated with the laser alone. These observations suggest that Q-switch II dye is an effective chemosensitizing agent for the Nd:YAG laser and could potentially be used to reduce collagen deposits in conditions such as keloids and hypertrophic scars.