title: Photosensitization of the rat endometrium following 5-aminolevulinic acid induced photodynamic therapy.
abstract: OBJECTIVE
  The impact of photodynamic therapy (PDT) on the endometrium following topical application of 5-aminolevulinic acid (ALA) was studied in a rat model. Study Design/
  
  
  METHODS
  Fluorescence microscopy revealed peak ALA to protoporphyrin IX (Pp IX) conversion 3-6 hours after application. Significantly higher Pp IX levels were observed in the endometrial glands compared with endometrial stroma and myometrium.
  
  
  RESULTS
  Histological studies showed PDT-induced endometrial destruction with atrophy 7-10 weeks after treatment. Reproductive performance studies demonstrated significant implantation failure in the treated uterine horns compared with controls. The number of implantation sacs in the treated and untreated horns was 0.4 +/- 0.3 and 8.9 +/- 1.0, respectively (P < 0.01).
  
  
  CONCLUSIONS
  We conclude that the high rate of Pp IX conversion in the endometrial glands can be exploited to treat dysfunctional uterine bleeding with PDT. In addition, this concept may also be applied to study endometrial regeneration and embryo implantation mechanisms.
authors.affiliation: Beckman Laser Institute and Medical Clinic, University of California, Irvine 92715, USA.
authors.forename: R A
authors.initials: RA
authors.lastname: Steiner
authors.forename: Y
authors.initials: Y
authors.lastname: Tadir
authors.forename: B J
authors.initials: BJ
authors.lastname: Tromberg
authors.forename: T
authors.initials: T
authors.lastname: Krasieva
authors.forename: A T
authors.initials: AT
authors.lastname: Ghazains
authors.forename: P
authors.initials: P
authors.lastname: Wyss
authors.forename: M W
authors.initials: MW
authors.lastname: Berns
mesh_terms: D000287:Administration, Topical; D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000818:Animals; D010064:Embryo Implantation / Q000187:drug effects; D004717:Endometrium / Q000187:drug effects* / Q000473:pathology; D005260:Female; D008856:Microscopy, Fluorescence; D010778:Photochemotherapy; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000622:Aminolevulinic Acid