Concurrent exercise prevents high-fat-diet-induced macrovesicular hepatic steatosis

Departments of Kinésiologie and Pathologie and Biologie Cellulaire, Université de Montréal, Montreal, Quebec, Canada H3C 3J7 The purpose of the present study was to assess the effect of an exercise training program conducted concurrently with a high-fat (HF)-diet regimen on the induction of hepatic steatosis. Two groups of rats were fed either a standard (SD) or a HF (40% kcal) diet for 8 wk and were additionally assigned either to a sedentary (Sed) or a treadmill-trained (TR) group. Training (5 days/wk) was initiated at the same time as the HF diet and was progressively increased, reaching 60 min at 26 m/min, 10% grade, for the last 4 wk. At the end of the 8-wk period, HF-Sed rats exhibited ~72% higher liver triacylglycerol concentration than SD-Sed rats (means ± SE: 17.15 ± 1.5 vs. 9.98 ± 1.0 mg/g; P 0.05). The different states of liver lipid infiltration after the HF diet in Sed and TR rats were associated with similar changes in plasma free fatty acids and glycerol, as well as with similar changes in fat pad weights, but not with plasma triacylglycerol levels. It is concluded that, after a HF-diet regimen of 8 wk in rats, hepatic steatosis occurs primarily via the accumulation of lipid as macrovesicles. Exercise training pursued at the same time completely prevents the HF-diet-induced macrovesicular hepatic steatosis. liver; fatty liver; lipid infiltration; lipid vacuoles; insulin resistance; adiposity