Photodynamic therapy of endometriosis with HpD (Photosan III) in a new in vitro model

As a new treatment model for endometriosis, photodynamic therapy was applied to endometriotic and endometrial cultures. It could be demonstrated that both endometrial components (epithelium and stroma) were present in the cultures, proved by immunocytology and electron microscopy. No major differences were seen between endometriotic and endometrial cells. The cultures were treated by HpD-sensitized PDT. Incubation time was 24 h and concentrations of 5 and 10 (mu) g/ml were used. Irradiation was performed by an argon-pumped dye laser at 630 nm with a power density of 80 mW/cm2. Evaluation both morphologically and by trypan blue exclusion test, was effected 24 h after irradiation. Toxicity in endometriotic and endometrial cultures was practically identical. Stroma cells were more sensitive to photodynamic treatment than epithelial cells. Complete stromal cell destruction was reached at 15 J/cm2, whereas epithelial cells showed 100 lethality at 40 J/cm2 (10(mu) g/ml HpD). These and subsequent results demonstrate that the sensitivity of stromal cells was about seven times higher than that of epithelial cells.