Oxidative status of erythrocytes, hyperglycemia, and hyperlipidemia in diabetic cats

Abstract

Background: Erythrocytes of diabetic cats have decreased superoxide dismutase activity, possibly indicative of oxidative stress. Hypothesis: Erythrocytes of diabetic cats undergo oxidative stress, which is caused by hyperglycemia and hyperlipidemia, and improves with treatment. Animals: Twenty-seven client-owned cats with diabetes mellitus, 11 matched healthy cats, and 21 purpose-bred healthy cats. Methods: Prospective study. Advanced oxidized protein products, carbonyls (protein oxidation by-products), and thiols (antioxidants) were quantified in erythrocyte membrane, thiobarbituric acid reactive substances (TBAR, lipid peroxidation by-products), and thiols in erythrocyte cytoplasm of all cats. Comparison were performed between diabetic and matched healthy cats, between diabetic cats achieving remission or not, and among purpose-bred cats after 10 days of hyperglycemia (n = 5) or hyperlipidemia (n = 6) versus controls treated with saline (n = 5) or untreated (n = 5). Results: Compared with controls, erythrocytes of diabetic cats initially had higher median membrane carbonyls (4.6 nmol/mg total protein [range: 0.1-37.7] versus 0.7 [0.1-4.7], P < 0.001). After 12-16 weeks of treatment in diabetic cats, carbonyls decreased by 13% (P