Serological and Uterine Biomarkers for Detecting Endometritis in Mares

Serological analysis may provide relevant information on endometritis diagnostics. Therefore, mares scheduled for AI with refrigerated semen, at the time of heat signs, underwent blood and uterine fluid samplings using a swab, uterine lavage for culture analysis, and treatment with human chorionic gonadotropin to induce ovulation. After 24–28 h, the mares were inseminated and, if positive at the culture test, treated with antibiotics chosen based on the susceptibility test. Uterine cells obtained by swabs were used for cytological examination with both classical and fluorescence techniques. Blood serum and uterine fluid samples were analyzed for assessing parameters related to redox balance, inflammation, and protease regulator potential. In blood serum, total antioxidant capacity, measured as the ferric reducing ability of plasma (FRAP), was significantly lower in cytologically endometritis-positive than -negative mares. In the uterine fluid, total thiol levels (TTL), nitric oxide metabolites (NOx), protease activity and total protein content varied significantly between groups. Although the cytological examination was more capable of discriminating between endometritis-positive and -negative mares in relation to the parameters examined, no statistically significant differences emerged in terms of pregnancy rate in relation to cytological and culture diagnosis as well as in mares diagnosed as positive and negative for endometritis.