A mouse model of salpingitis and subsequent tubal infertility induced by a human strain of Chlamydia trachomatis has been studied. C3H/He female mice were inoculated into the ovarian bursa. Some of the mice (six infected, five controls) were killed on days 15 and 23 and the remaining animals (10 infected, 10 controls) were mated on day 15. On day 15, the infection was maximal with intratubal inflammation, elevated antichlamydial antibody titre and positive cultures in 12 cases out of 16. After 19 weeks of housing with the male, the proportion of fertilized females was significantly lower in the infected group (20% versus 100% in the control group P less than 0.01). In the killed mice, hydrosalpinx and or tubal occlusion were noted at this time in nine cases out of 10, despite an apparent bacteriological healing.

We used a mouse model of acute chlamydial salpingitis to evaluate the efficacy of roxithromycin in preventing irreversible inflammatory damage leading to tubal infertility. Female C3H/He mice were genitally inoculated with a human strain of Chlamydia trachomatis and then treated with roxithromycin glutamate subcutaneously. Treatment was initiated either 7 or 10 days postinfection (p.i.) and continued for 7 days at a dosage of 50 or 100 mg/kg of body weight per 24 h. The course of the disease was monitored serologically, bacteriologically, and histologically. At the end of the treatment, the mice were encaged with males and their reproductive capacity was recorded over a 19-week period. The protective effect of roxithromycin was assessed in terms of fertility parameters in comparison with values for noninfected control mice. When treatment was initiated on day 7 p.i. and given in twice-daily 25-mg/kg doses, all the mice remained fertile and the total number of offspring was similar to that of sham-infected mice (17.3 3.3 versus 17.2 + 2.3). When treatment was initiated on day 10 p.i. and given in a single daily dose of 50 or 100 mg/kg, 90 and 70% of the mice, respectively, remained fertile; however, in terms of total offspring, fertility was lower in the group treated with the lower dose (5.6 1.4 versus 13.0 3.8). Roxithromycin was found to be effective against C. trachomatis in the mouse genital tract, but fertility was only partiaHly preserved when the time between infection and treatment was prolonged.