PHOTODYNAMIC THERAPY OF RAT ENDOMETRIUM SENSITIZED WITH TIN ETHYL ETIOPURPURIN

Study Objective. To evaluate endometrial ablation in the rat using pho todynamic therapy and the photosensitizer tin ethyl etiopurpurin (SnET 2). Design. Laboratory research. Setting. A pharmaceutical and device manufacturing company. Materials. Forty-five healthy female rats (age 8-10 wks). Interventions. Groups of three to five rats were given SnET 2 by either intrauterine or intravenous administration. Light treatmen t was given at either 3 or 24 hours after SnET2 administration at a li ght dose of 75, 150, or 200 J/cm. Measurements and Main Results. A flu orescence detection system was employed to determine relative drug upt ake of SnET2 into uterine tissue. The highest levels of SnET2 were det ected at 3 hours. After light treatment, responses of uterine tissues were evaluated histologically. The best endometrial ablation was seen when SnET2 was given by intrauterine administration with light treatme nt at 150 J/cm 24 hours later. A consistent transmural response was se en with this route of administration at 200 J/cm. Intravenous SnET2 ga ve inconsistent responses. In light-only controls, all light doses cau sed no tissue response. The depth of necrosis in tissues treated with photodynamic therapy were light-dose dependent. Conclusion. With eithe r route of SnET2 administration, drug uptake was confirmed and a light -dose-dependent response in the walls of rat uterine horns was demonst rated.