THE USE OF TRANSCUTANEOUS PHOTODYNAMIC THERAPY IN THE PREVENTION OF ADJUVANT-ENHANCED ARTHRITIS IN MRL LPR MICE/

The use of transcutaneous photodynamic therapy (PDT) has been investig ated in the prevention of adjuvant enhanced arthritis in MRL/lpr mice. Mice receiving adjuvant were treated with PDT at 10-day intervals sta rting on the day of adjuvant administration. PDT was carried out by in travenous injection of the photosensitizer, benzoporphyrin derivative- monoacid ring A, followed by its transcutaneous activation with light. Adjuvant-injected animals displayed a delayed onset and reduced incid ence and severity of arthritis when compared to untreated animals. Mos t importantly, inflammatory structural damage to cartilage and bone ti ssues was prevented by PDT. PDT was found to have no adverse effects o n animals as assessed by mitogen responses, hematopoiesis, and serum e nzyme levels. As mitogen-activated MRL/lpr splenocytes were shown to b e more susceptible to in vitro photodynamic treatment, it is postulate d that the observed effects were the result of selective destruction o f adjuvant-activated lymphocytes in the circulation and/or joints. (C) 1994 Academic Press, Inc.