The aim of the study was to evaluate the oxygen metabolism of neutrophils in peripheral blood of mares in relation to intensity of endometrium inflammations. The study involved 36 half-breed mares, aged 4-22 years, showing fertility disturbances. In 26 mares neutrophils were found in uteral smears, which indicated endometritis (15 - moderate inflammation and 11 - severe inflammation). In the rest mares, cytological examination excluded inflammation. Blood samples were evaluated in terms of neutrophils chemiluminescence without stimulation (CL-WS) and with stimulation by opsonised zymosan (CL-OZ). The study demonstrated (only in case of CL-WS) an increase in chemiluminescence of cells in mares with a severe inflammation of the endometrium. The increased chemiluminescence activity was accompanied by a decrease in activation index (OZ/WS) of neutrophils, suggesting some imbalance between production and elimination of reactive oxygen species (ROS). The correlation analysis demonstrated a statistically significant relation between the intensity of the uterus inflammation, which was verified by cytological examination and CL-WS of peripheral blood neutrophils, as well as their activation index. The obtained results suggest that activated neutrophils are an important source of ROS which can play a role in the pathogenesis of endometritis in mares.
