THE EFFECTS OF UTERINE OZONE INSUFFLATION IN MARES AFFECTED BY ENDOMETRITIS: PRELIMINARY RESULTS

Endometritis represents one of the main causes of subfertility in mares. Recently, alternative therapies such as ozone uterine insufflation have been proposed [1] [2]. The present study aimed to describe uterine ozone (O3) effects on mares affected by endometritis in terms of pregnancy rate (PR), cytological, microbiological, and histopathological findings (altogether: diagnostic procedures = DP). In Study 1, five former embryo recipient mares, aged 10-21 years, were artificially inseminated (AI) for 2 control cycles (N=10) with fresh pooled semen from two fertile stallions and flushed for embryo recovery. In another 2 cycles, the same mares underwent DP and O3 treatment, in the first cycle, and DP, AI, with the same stallions, and uterine flushing for embryo recovery, in the second cycle. In Study 2, five barren commercial mares, aged 16-20 years, underwent DP followed by O3 treatment, in the first cycle, and DP, AI, with different commercial stallions and semen, and pregnancy diagnosis, in the second cycle. In both studies, treatment consisted of intrauterine O3 insufflation (volume: 300 ml; [O3]: 40 μg/ml), for 3 consecutive days. Samples for cytological and microbiological evaluation were collected by uterine lavage with 100 ml of Sterile Ringer Lactate, while samples for histopathology by endometrial biopsy. Fisher exact test was used to compare results pre and post O3 treatment, when indicated. In Study 1, 9/10 cycles (90%) before and 4/5 (80%) after O3 treatment resulted in an embryo recovery (NS), while, in Study 2, 0/5 mares before and 4/5 (80%) after O3 treatment were pregnant at 14 and 60 days (P=0.0476). Considering Study 1 and 2 altogether, only two mares resulted positive at cytological examination pre O3 treatment and both were negative after; only one mare was cultured positive, before and after treatment, and histopathology score improved post O3 treatment in 6/10 mares (NS). In conclusion, intrauterine ozone treatment for equine endometritis, appeared not harmful for fertility and able to improve pregnancy rates in barren mares. Further studies in a larger number of animals are warranted to confirm these results and to better describe the effects of such treatment on uterine quality.