Evidence of lasting functional destruction of the rat endometrium after 5-aminolevulinic acid-induced photodynamic ablation: prevention of implantation.
OBJECTIVE
We evaluated disruption of endometrial function after treatment with 5-aminolevulinic acid with or without light exposure.


METHODS
In a conventional laboratory setting adult Sprague-Dawley female rats were treated with various doses of 5-aminolevulinic acid in one uterine horn and saline in the contralateral horn. Three hours after treatment both uterine horns were exposed to light, and the rats were bred to a fertile male 10 or 60 days later. Ablation of endometrium was evaluated by both rate of implantation and histologic features.


RESULTS
In the absence of light exposure 5-aminolevulinic acid had no significant effect on the rate of implantation, compared with saline (76% vs 92%, n = 25, p > 0.05). In contrast, 5-aminolevulinic acid treatment plus light exposure profoundly decreased the rate of implantation in the 5-aminolevulinic acid-treated uterine horns of rats bred 10 days (3.8% vs 100%, n = 26, p < 0.001) or 60 days after treatment (16.7% vs 100%, n = 24, p < 0.001). Histologic examination revealed that the 5-aminolevulinic acid plus light-treated uterine horns were completely devoid of endometrium.


CONCLUSIONS
Photodynamic treatment with 5-aminolevulinic acid resulted in a persistent disruption of rat endometrial function and was consistent with the histologic evidence of complete endometrial ablation. In addition, a partial destruction of myometrium adjacent to endometrium was observed. The myometrial damage may be through a nonphotodynamic mechanism because myometrium is unable to synthesize protoporphyrin IX from 5-aminolevulinic acid.
Yang
J Z
JZ
Department of Physiology, Queen's University, Kingston, Ontario, Canada.
Van Vugt
D A
DA
Kennedy
J C
JC
Reid
R L
RL
D000622:Aminolevulinic Acid / Q000494:pharmacology*; D000818:Animals; D010064:Embryo Implantation / Q000187:drug effects*; D004717:Endometrium / Q000033:anatomy & histology / Q000187:drug effects* / Q000528:radiation effects; D005260:Female; D008027:Light; D010778:Photochemotherapy; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014599:Uterus / Q000033:anatomy & histology / Q000187:drug effects / Q000528:radiation effects
D000622:Aminolevulinic Acid