[Benzoporphyrin derivative mono acid for photodynamic therapy of the endometrium]

The aim was to study the impact of photodynamic therapy (PDT) on the endometrium after local intrauterine application of photosensitiser (Ps) and laser light without sensitising the skin. To our knowledge Benzoporphyrin Derivative Mono Acid (BPD) was used for the first time for this purpose in the rat model. The advantage of using BPD is the fact that light of 690 nm (maximum absorption) penetrates deeper into tissue and shows less absorption by haemoglobin. Low-light level tissue fluorescence imaging revealed a distinct positive endometrium-to-myometrium ratio within the first 12 hours. Relative fluorescence was highest in the endometrial glands and lowest in the myometrium. After 12 hours the intensity of fluorescence levelled off in all compartments and values of the glands approached close to those of the other layers. REPRODUCTIVE PERFORMANCE AFTER PDT: There was a significant difference in nidations (p < 0.03) in the treated left uterine horn as compared to the untreated right horn and the control animals (light/no drug and drug/no light). HISTOLOGICAL CHANGES: Following PDT a marked atrophy of the endometrial layer was observed in most animals leaving just a single cell epithelial layer covering the myometrium. SKIN PHOTOSENSITIVITY: None of the animals showed any alterations in the light treated skin area at any time. These promising results show that PDT of the endometrium is possible after topical application of the photosensitising drug and the laser light without provoking skin sensitivity.