A low-protein, high-carbohydrate diet in the short term induces oxidative stress in the cardiac muscle of rats

OBJECTIVES: Oxidative stress occurs when the production of reactive species exceeds the antioxidant capacity. In the heart muscle, this imbalance is associated with heart failure. The objective of this study was to evaluate the markers of cardiac damage and the antioxidant system in the hearts of rats fed a low-protein, high-carbohydrate diet for 15 days. METHODS: Male Wistar rats (Rattus norvegicus), weighing 90-100 g and approximately 21 days old were used (CEUA: n° 23108.006061/2021-11). The animals were randomly divided into two groups: low-protein, high-carbohydrate (LPHC), animals fed 77% carbohydrates and 6% protein, and control (C), animals fed a normoprotein diet (64% carbohydrates and 17% proteins). At the end of day 15, the animals were anesthetized and euthanized, and blood and heart muscle were collected. RESULTS: An increase in the content of carbonylated proteins, substances reactive to thiobarbituric acid, and catalase, glutathione peroxidase, glutathione-S-transferase, and myeloperoxidase (serum + plasma) activity was observed. A reduction in absolute heart weight, total antioxidant capacity, reduced glutathione, intracellular oxidation, superoxide dismutase gene expression, glutathione reductase, and myeloperoxidase (heart muscle) activity was observed in LPHC animals compared with those in group C. CONCLUSIONS: These data suggest that consuming the LPHC diet for 15 days may lead to an oxidative imbalance in the heart muscle, altering the antioxidant capacity induced by stress.