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Updated: Aug 13, 2026
Methods to Inhibit Bacterial Pyomelanin Production and Determine the Corresponding Increase in Sensitivity to Oxidative Stress
Published on: August 31, 2015
Systemic oxidative stress, selected nonenzymatic exogenous and endogenous antioxidants, and hematologic and
Cevdet Peker1, Eyyüp Hakan Uçar1, Gamze Sevri Ekren Aşıcı2
1Department of Obstetrics and Gynecology, Faculty of Veterinary Medicine, Aydin Adnan Menderes University, Aydin, Turkey.
Objective:
To evaluate oxidative stress biomarkers (malondialdehyde [MDA] and total oxidant status [TOS]), selected nonenzymatic endogenous (glutathione [GSH], albumin, and bilirubin), and, for the first time, exogenous (ascorbic acid, α-tocopherol, β-carotene, and retinol) antioxidants together with hematobiochemical alterations in canine pyometra.
Methods:
33 bitches were classified into pyometra (n = 17) or control (16) groups based on clinical and hematological evaluations. Ascorbic acid was measured by the phosphotungstate method; GSH, MDA, β-carotene, and retinol spectrophotometrically; α-tocopherol by ELISA; and TOS by a colorimetric assay. Hematobiochemical variables were analyzed using automated analyzers.
Results:
Bitches with pyometra had higher MDA and TOS than controls (36.30 ± 13.95 µmol/L vs 24.61 ± 4.80 µmol/L and 27.78 ± 15.51 µmol H2O2 Eq/L vs 13.13 ± 1.84 µmol H2O2 Eq/L; Hedges' g = 1.08 and 1.27, respectively). Glutathione tended to increase in pyometra (12.04 ± 10.80 nmol/g Hb vs 6.40 ± 2.97 nmol/g Hb; Hedges' g = 0.68), whereas the other antioxidants were similar between groups. Pyometra was also associated with leukocytosis, neutrophilia, monocytosis, decreased erythrocyte counts and Hct, and increased ALP, ALT, and cholesterol.
Conclusions:
Canine pyometra is accompanied by systemic oxidative stress and hematobiochemical alterations. However, circulating nonenzymatic antioxidants remained largely unchanged, suggesting complex antioxidant regulation rather than simple depletion. Increased GSH may reflect a thiol-based compensatory response to increased oxidative burden.
Clinical Relevance:
Nonenzymatic antioxidant regulation in canine pyometra may be more complex than simple depletion. Further studies incorporating disease-severity stratification and tissue-level assessments of both enzymatic and nonenzymatic antioxidants are warranted.
