Treadmill exercise training enhances ATP-binding cassette protein-A1 (ABCA1) expression in male rats’ heart and gastrocnemius muscles

Background: Heart and gastrocnemius muscles function as highly oxidative and fast oxidative-glycolytic tissues and consume lipid and other metabolites at rest and during exercise. Exercise at low to moderate intensity increases fat mobilization and lipid metabolism, and several genes are involved in lipid and cholesterol metabolism (e.g. membrane-associated fatty acid transport proteins and ATP-binding cassette transporters [ABC] from adipose and other tissues). Objectives: The purposes of the current study were to investigate the effect of chronic physical exercise training on (a) heartand gastrocnemius-muscle ABCA1 expression and (b) plasma apolipoprotein-A (apo-A) and pre-β-HDL concentrations. Materials and Methods: 10 adult male Wistar rats (12 to 14 weeks old, 200 to 220 g) were divided into control (n = 5) and training (n = 5) groups. The training group was exercised on a motor-driven treadmill at 25 m/min (0% grade) for 60 min/day, 5 days/week, for 12 weeks. Rats were sacrificed 48 h after the last exercise session. A portion of the heart and gastrocnemius muscles were excised, immediately cleaned, washed in icecold saline, and frozen in liquid nitrogen for extraction of ABCA1 mRNA. Unpaired t student tests were used to analyze the data. Results: Higher and significant ABCA1 expression, plasma apo-A, and pre-β-HDL concentrations were found in the trained rats than in the control group. Conclusions: The results indicate that exercise-training-induced ABCA1 expression in heart and gastrocnemius muscles was accompanied with higher plasma apo-A and pre-β-HDL concentrations. This might reinforce the initiation of reverse cholesterol transport process. A R T I C L E I N F O Article history: Received: 20 Oct 2010 Revised: 5 Nov 2010 Accepted: 1 Jan 2011