Element status and inflammatory response in dogs with pyometra

Pyometra is a life-threatening disease characterized by persistent endometrial inflammation and bacterial colonization, which occur through enzymatic and non-enzymatic antioxidant mechanisms. Minerals and trace elements have effective roles in numerous metal-dependent enzyme and protein activities. The aim of this study is to evaluate the monocyte to lymphocyte ratio (MLR), neutrophil to lymphocyte ratio (NLR), white blood cell (WBC), C-reactive protein (CRP), albumin (ALB), progesterone (P4) levels, serum and uterine tissue iron (Fe), copper (Cu), selenium (Se), zinc (Zn), magnesium (Mg), manganese (Mn) concentrations and Cu/Zn ratio in dogs with pyometra and healthy controls.

This study included 43 dogs divided into two groups: a Control Group (n = 23) and a Pyometra Group (n = 20), 12 with open-cervix and 8 with closed-cervix pyometra. All animals underwent ovariohysterectomy, and intrauterine swab samples were collected for bacterial culture. Mineral analysis in serum and uterine tissue was performed using inductively coupled plasma optical emission spectrometry (ICP-OES).

All dogs in this study were multiparous and at the luteal phase of the estrous stage. Isolated microbial agents in Group PYO were Gram-negative bacteria. Increase in P4 (P = 0.01), CRP, WBC, MLR, NLR, and decrease in ALB levels observed in Group PYO (P < 0.001). Significant rise in serum and uterine Cu, Fe, and Mg concentrations and decrease in serum and uterine Se and Zn concentrations were determined in pyometra cases (P < 0.001). Also, Cu/Zn ratio both in serum and uterine tissue samples were significantly higher in Group PYO than in Group C (P < 0.001).

Changes in CRP, WBC, MLR, NLR, P4 and ALB reflected the inflammatory response and immune deficiency in the presence of canine pyometra. Significant differences in serum and uterine Cu, Fe, Mg, Se, and Zn concentrations in pyometra cases proved that these elements can be used as non-enzymatic antioxidant biomarkers. To our knowledge, the present study explored firstly Cu/Zn ratio in canine pyometra cases as an oxidative stress biomarker. It was concluded that Mg, Cu/Zn and trace elements can be effective markers to assess the non-enzymatic antioxidant status in canine pyometra cases.