Effectiveness of Ozone Therapy in The Treatment of Endometritis in Mares.

Abstract: Endometritis is defined as inflammation of the endometrium that may be acute or chronic, infectious, or non-infectious. Endometritis is an important cause of subfertility in mares. Considering the antimicrobial characteristics, immune-stimulating ability, and low cost of ozone (O3) therapy, we aimed to evaluate the effectiveness of intrauterine O3 therapy as an alternative treatment for endometritis in mares. Twenty-five mares with a known reproductive history of uterine infection and inflammation were allocated into three groups: Group 1 (control; n = 7), uterine lavage with Ringer's lactate solution; Group 2 (O3-gas; n = 9), uterine lavage with Ringer's lactate solution followed by uterine insufflation with O2-O3 gas mixture containing 40 µg O3 mL-1 for 10 minute; and Group 3 (O3-oil; n = 9), uterine infusion of ozonized sunflower oil. Uterine inflammation was evaluated through a uterine cytological examination (cytobrush) and uterine culture (swab) for microbiological content before and after all treatments. In assessments of uterine cytology, the average number of neutrophils/field changed from 9.14 ± 3.02 to 7.71 ± 3.59 in the control group, from 10.67 ± 3.84 to 2.89 ± 3.59 in the O3-gas group, and from 6.44 ± 2.79 to 6.55 ± 7.18 in the O3-oil group post-treatment. The pre- and post-treatment findings in the mares treated with ozonized gas were significantly different (P < .05), unlike the findings for the mares in the control and O3-oil groups. All mares (25/25) showed a positive uterine culture before treatment. After treatment, the percentage of mares showing positive culture results was 57%, 11%, and 22% in the control, O3-gas, and O3-oil groups, respectively. Our results showed the effectiveness of two groups (O2-O3 gas mixture and ozonized sunflower oil) for the treatment of uterine infections in mares. Thus, direct intrauterine O3 gas infusion has been shown to be effective in treating endometritis in mares, reducing both inflammation and uterine infection.