Photodynamic Therapy: A New Approach to Remove Embryos of the Wistar Rat

Background: Photodynamic therapy (PDT) is a promising new cancer treatment strategy which inactivates tumor cells by simultaneoulsy using light and a photosensitizer. The similarity between tumors and newly implanted embryos is notable. Extrauterine pregnancy (EUP) does not have a definite treatment and previous therapeutic options (medical and surgical) have not been effective or suitable. Therefore, PDT is suggested as a possible treatment for EUP. Materials and Methods: The photosensitizer, hematoporphyrin, was injected locally into the placenta of one selected embryo from a pregnant Wistar rat (E15). Then, a laser beam was illuminated at the same point and 48 hours later, changes in the embryo and placenta were investigated. Furthermore, the integrity of the uterus was examined by macroscopic evaluation and sonographic images. Results: Sections obtained from treated and control groups demonstrated that the embryo and placenta were damaged in the PDT group, whereas the control ones were intact. Furthermore, macroscopic observations and sonographic images during the second parturition after treatment showed that the uterus was intact and fertility was preserved. Conclusion: Successful ablation of the treated embryo with no clear damage to the uterus attests to the success of this approach. The successful use of hematoporphyrin, as a first generation photosensitizer, should be further investigated for its possible clinical applications.