High efficacy of photodynamic therapy on rat endometrium after systemic administration of benzoporphyrin derivative monoacid ring A.

BACKGROUND

The aim of this study was to evaluate the effect of the benzoporphyrin derivative monoacid ring A (verteporfin)-mediated photodynamic therapy (PDT) on rat endometrium and to determine the optimal drug concentration for endometrial ablation.

METHODS

Five minutes after i.v. injection of different concentrations of verteporfin into 24 female Sprague-Dawley rats, 630 nm light treatment was delivered for 500 s (120 J/cm2) to the left horn of the uterus. The 24 rats were divided into six groups according to the drug dose injected, four rats per group: group I (2 mg/kg), group II (1 mg/kg), and groups III, IV, V and VI with 0.5, 0.25, 0.125 and 0.0625 mg/kg respectively. Four days later, the rat uteri were analysed by light microscopy.

RESULTS

Endometrial destruction was seen in all six groups, with the most significant result in group I (P<0.008). Conservation of the myometrium was most significant in groups III, IV, V and VI. Acute inflammatory cells in the stromal endometrium were recorded mainly in groups I and II. However, the drug dosage that was most significant in destroying the glands with conservation of the myometrium and not causing severe inflammation was between 0.5 and 0.125 mg/kg.

CONCLUSIONS

Verteporfin was effective in endometrial ablation in all our animal groups, and the dose range of 0.5-0.125 mg/kg appeared to be adequate. This observation will have to be scaled for clinical application.