Photodynamic destruction of endometrial tissue with topical 5-aminolevulinic acid in rats and rabbits.
OBJECTIVE
The goal of this study was to determine the optimal parameters for photodynamic endometrial destruction with topically applied 5-aminolevulinic acid, a precursor for the endogenous synthesis of the fluorescent photosensitizer protoporphyrin IX.


METHODS
5-Aminolevulinic acid pharmacokinetics were measured in rat and rabbit models by analyzing tissue frozen sections 3 to 12 hours after topical administration. Dose-response studies were conducted for 100 to 400 mg/ml 5-aminolevulinic acid. Photodynamic therapy was performed intraluminally, and tissue morphologic features were evaluated 3 and 7 days after treatment.


RESULTS
Peak fluorescence was observed 3 hours after topical administration. Glandular fluorescence significantly exceeded stromal and myometrial in all studies, particularly for 200 mg/ml 5-aminolevulinic acid. Histologic studies revealed persistent epithelial destruction with minimal regeneration.


CONCLUSIONS
Topical 5-aminolevulinic acid photodynamic therapy can be used for highly effective, long-lasting destruction of endometrial epithelium. However, optical dosimetry can vary, particularly in the rabbit model, and this appears to have an impact on long-term reepithelialization.
Wyss
P
P
Beckman Laser Institute and Medical Clinic, Irvine, CA 92715.
Tromberg
B J
BJ
Wyss
M T
MT
Krasieva
T
T
Schell
M
M
Berns
M W
MW
Tadir
Y
Y
D000287:Administration, Topical; D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004717:Endometrium / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005260:Female; D005453:Fluorescence; D008855:Microscopy, Electron, Scanning; D010778:Photochemotherapy; D011524:Protoporphyrins / Q000378:metabolism; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus / Q000187:drug effects / Q000473:pathology
D011524:Protoporphyrins; D000622:Aminolevulinic Acid; C028025:protoporphyrin IX