Uterus and endometrium: Regeneration processes in rabbit endometrium: a photodynamic therapy model

The origin and process of regeneration in rabbit endo metriumwas evaluated following photodynamic epithelial destructionusing topically applied anilnolevulinic acid (ALA). Selectivedestruction of endometrial epithelium was performed using photodynamictherapy (PDT). ALA was diluted to 200 mg/ml dextran 70 shortlyprior to adininistra tion. A volume of 1.2 ml was injected intothe left uterus. Intrauterine illumination (wavelength 630 nm,light dose 40–80 J/cm²was performed 3 h after drug administration.Tissue morphology was evaluated by light and scanning electronmicroscopy 1, 3, 7 and 28 days post-treatment (three animalsat each dine-point). Regeneration of the endometriwn followingepithelial ablation by PDT was fully activated after 24 h andwas completed after 72 h. Endometrial surface generation occurredby proliferation, originating primarily in deeper regions ofthe glands. Findings from our morphological follow-up studysupport the origin of endometrial regeneration being mainlyfrom undifferentiated stem cells and residual glandular epithelium.