Evaluation of uterine antioxidants in bitches suffering from cystic endometrial hyperplasia-pyometra complex

Cystic endometrial hyperplasia-pyometra complex (CEH-P) is a common disease in sexually mature bitches. Disease progression leads to oxidative stress, resulting in the depletion of uterine antioxidants and lipid peroxidation of associated cells, which further aggravates the condition. The concentration of antioxidant enzymes, the level of lipid peroxidation within the uterine tissue, and its reflection in the serum and urine need to be elucidated. The aim of this study was to analyze the concentration of antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), and the lipid peroxidation marker malonaldehyde (MDA) in three types of samples, i.e., serum, urine, and uterine tissue. For this purpose, 58 pyometra-affected and 44 healthy bitches were included in the present study. All animals underwent ovariohysterectomy (OVH). Our data indicated highly significant difference (p<0.01) in the antioxidant concentrations of uterine, serum and urine samples. Furthermore, there was a highly significant (p<0.01) difference in the serum levels of ferric reducing antioxidant power (FRAP) and free radical scavenging activity (FRSA) indicated poor capacity to overcome oxidative stress in the CEH-Pyometra condition. We showed that CEH-P induces oxidative stress, which further depletes the antioxidant enzyme reserves in the uterus. Thus, the weak antioxidant defence predisposes to uterine damage and disease progression. The simultaneous depletion of antioxidants and an increase in lipid peroxidation in the serum and urine may also act as early indicators of uterine pathology.