PD547 - HIGHLY PROCESSED DIETS INDUCE METABOLIC DYSFUNCTION PARTIALLY RESCUED BY LONG-TERM MODERATE EXERCISE IN RATS

PD547

HIGHLY PROCESSED DIETS INDUCE METABOLIC DYSFUNCTION PARTIALLY RESCUED BY LONG-TERM MODERATE EXERCISE IN RATS

G. Almer^1,*, H.-J. Gruber¹, D. Stefanizzi², K. J. Sobolewska¹, F. Curcio^2,3, K. Skok^4,5, D. Verma⁶, S. Sedej^6,7, A. P. Beltrami^2,3, M. Herrmann¹

¹Medical University of Graz, Clinical Institute for Medical and Chemical Laboratory Diagnostics, Graz, Austria, ²University of Udine, Department of Medicine, ³ASUFC, Institute of Clinical Pathology, Udine, Italy, ⁴Medical University of Graz, Diagnostic and Research Institute of Pathology, Graz, Austria, ⁵University of Maribor, Institute of Biomedical Sciences, Maribor, Slovenia, ⁶Medical University of Graz, Department of Cardiology, Graz, Austria, ⁷University of Maribor, Institute of Physiology, Maribor, Slovenia

Rationale: Unhealthy dietary patterns and physical inactivity are major contributors to the global burden of metabolic disease. While experimental high-fat diets are well-established disease drivers, the metabolic consequences of highly processed “purified” rodent diets used as standard controls in preclinical research remain underappreciated. Here we investigated the effects of purified control and high-fat diets, and the potential of long-term moderate exercise to counteract diet-induced metabolic deterioration.

Methods: Young adult female Long-Evans rats were divided into five groups (n ≥ 11): sedentary normal chow (sND), sedentary purified control diet (sCD), sedentary purified high-fat/high-cholesterol diet (sHFCD), and exercising counterparts on CD and HFCD. Training consisted of treadmill running (10° incline, 30 min/day, 4 days/week) for 8 months to simulate decades of human intervention. Respiratory exchange ratio (RER) was assessed via metabolic cages prior to tissue collection.

Results: Compared to sND, sCD animals showed greater weight gain, increased adiposity, reduced RER, dyslipidemia (elevated triglycerides, reduced HDL), and higher serum leptin, fructosamine, total bilirubin, and IL-1 receptor agonist. Liver histology revealed moderate macrovesicular steatosis. Exercise normalized most parameters toward sND levels. The sHFCD group exhibited a more severe metabolic phenotype, with a shift to hepatic microvesicular steatosis and inflammation foci. Here exercise only partially compensated these additional effects.

Conclusion: Purified control diets exert unexpectedly pronounced metabolic and hepatic consequences independent of fat content — a relevant confounder in preclinical diet research. Long-term moderate exercise effectively mitigates purified diet-induced metabolic dysfunction, but its protective capacity is attenuated under additional high-fat conditions.

Disclosure of Interest: None declared