Photodynamic therapy of rat endometrium sensitized with tin ethyl etiopurpurin

To evaluate endometrial ablation in the rat using photodynamic therapy and the photosensitizer tin ethyl etiopurpurin (SnET2).

Laboratory research.

A pharmaceutical and device manufacturing company.

Forty-five healthy female rats (age 8-10 wks).

Groups of three to five rats were given SnET2 by either intrauterine or intravenous administration. Light treatment was given at either 3 or 24 hours after SnET2 administration at a light dose of 75, 150, or 200 J/cm.

A fluorescence detection system was employed to determine relative drug uptake of SnET2 into uterine tissue. The highest levels of SnET2 were detected 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 treatment at 150 J/cm 24 hours later. A consistent transmural response was seen with this route of administration at 200 J/cm. Intravenous SnET2 gave inconsistent responses. In light-only controls, all light doses caused no tissue response. The depth of necrosis in tissues treated with photodynamic therapy were light-dose dependent.

With either route of SnET2 administration, drug uptake was confirmed and a light-dose-dependent response in the walls of rat uterine horns was demonstrated.