THE INFLUENCE OF PENTOXIFYLLINE (TRENTAL) AN THE ANTIFERTILITY EFFECTSF INTRAUTERINE-DEVICES IN RATS

Objective: To test the hypothesis that the inflammatory response stimu lated by intrauterine devices (IUDs) plays a role in the antifertility action of IUDs. We treated rats with pentoxifylline (Trental; Hoechst -Roussel Pharmaceuticals, Inc., Somerville, NJ) and evaluated its effe ct on the anti-implantation action of IUDs. The number of embryos in t reated compared with untreated rats was determined. Design: Breeder fe male Sprague-Dawley rats (Harlan Sprague Dawley, Indianapolis, IN) wer e randomized into one of five test groups (n = 20 per group). A monofi lament nylon IUD was inserted transcervically into one horn of the bic ornuate uterus in two groups. The IUD-bearing groups received either i ntraperitoneal (IF) injections of pentoxifylline (45 mg/kg per every 1 2 hours) or normal saline (NS). The two non-IUD-bearing groups receive d IP injections of pentoxifylline or NS. The non-IUD group was not inj ected. All injections were administered daily for 21 days and the anim als then mated. Successful mating was determined by the presence of sp ermatozoa in vaginal washings. The injections of pentoxifylline or NS were continued until day 12 of pregnancy when the rats were killed. Th e total number of embryos in each uterine horn was determined. Setting : University research laboratory. Results: Embryo numbers (1.0 +/- 0.6 [mean +/- SEM]) were reduced in the IUD horn compared with the contra lateral non-IUD horn (6.4 +/- 1.0) and with the uterine horns from eac h of the four other test groups. The number of embryos were increased in the IUD horn (3.5 +/- 0.9) of the pentoxifylline-treated rats. Conc lusion: Pentoxifylline appeared to reduce the contraceptive effectiven ess of the IUDs in this model.