STRUCTURAL AND FUNCTIONAL-EFFECTS OF ENDOMETRIAL PHOTODYNAMIC THERAPYIN A RAT MODEL

OBJECTIVE: Our purpose was to determine the optical dose required for irreversible endometrial destruction and prevention of implantation by photodynamic therapy with topical 5-aminolevulinic acid. STUDY DESIGN : Three hours after drug application 74 female Sprague-Dawley rats rec eived varying doses of 630 nm of light delivered by an intrauterine cy lindric diffusing fiber. RESULTS: A 64 J/cm(2) in situ optical dose re sulted in long-term irreversible endometrial destruction; 43 J/cm(2) d amaged endometrial stroma and myometrium but not glandular epithelium 1 day after photodynamic therapy. At this lower light dose endometrium regenerated to full thickness within 3 weeks; however, implantation s acs were significantly reduced. CONCLUSIONS: Photodynamic destruction of glandular epithelium accompanies irreversible endometrial ablation, whereas isolated stromal damage leads to reproductive impairment only . The optical dose required for endometrial ablation is approximately 1.5-fold higher than for reproductive impairment (functional damage) b ecause of differential cell photosensitivity.