Animal models
Three months old male Sprague Dawley (SD) rats were purchased from BioLASCO (Taipei, Taiwan). The rats were housed in cages with temperature maintained at 24 ± 2 °C, 55 ± 10% of humidity and 12 h light-dark cycle and were provided a standard laboratory diet (Lab Diet 5001; PMI Nutrition International Inc., Brentwood, MO, USA) and drinking water ad libitum. After one week adaptation the rats were divided into four groups: Control group (C, n=9), Exercise training group (E, n=9), Aging group (A, n=9), Aging group with Exercise training (AE, n=9). The control rats were given 0.9% saline (IP, 1 mL) and the aging induced groups (A and AE) received D-galactose (150 mg/kg body weight) for eight weeks. The swimming training protocol was performed as mentioned in other reports [50]. The Initial exercise training during the first two weeks was given for 20 min/day for five times a week. In the third week the timing of the swimming exercise training time was increased to 30 min per day and from fourth to eighth week the swimming exercise training was given for 60 min/day. The rats swam individually in a water bath (60 × 90 cm, 50 cm depth) with the water temperature maintained at 35 ± 1°C. All protocols were approved by the Institutional Animal Care and Use Committee of China Medical University, Taichung, Taiwan. The study followed the principles of laboratory animal care (NIH publication).
Protein extraction and western blotting
Heart tissue extracts obtained by homogenizing in a lysis buffer (0.05M of pH 7.4 Tris-HCl, 1 mM EDTA, 0.15 M NaCl, 1% NP-40, 0.25% deoxycholic acid) at a ratio of 100 mg tissue/1 mL buffer. The homogenates were kept on ice and the proteins in the supernatants were collected by centrifugation at 13,000 rpm for 40 min and stored at -80 °C. Protein concentrations in heart tissue extracts were determined by the Lowry protein assay. Western blotting was performed following methods mentioned in other reports with slight modification [51]. The protein samples were separated in 8%-12% SDS polyacrylamide gel electrophoresis (SDS-PAGE) under 75 V for 120 min. The separated proteins were subsequently transferred to PVDF membranes (GE healthcare limited, Buckinghamshire, UK) under 50 V for 3 h. The membranes were blocked in 3% bovine serum albumin (BSA) in tris-buffered saline and were then hybridized with primary antibodies including TNF-R (SC-1070, Santa Cruz Biotechnology, California, California, USA), TNF-α (SC-1350, Santa Cruz Biotechnology, California, California, USA), iNOS(610328, BD, New Jersey, USA), p-NFκB (#3033L, Cell Signaling, Maryland, USA) , COX-2(SC-1745, Santa Cruz Biotechnology, California, USA),α-tubulin (SC-5286, Santa Cruz Biotechnology, California, USA), p-FOXO1(#9464, Cell Signaling, Maryland, USA), FOXO3a(#2497, Cell Signaling, Maryland, USA), p-FOXO3a(#9466, Cell Signaling, Maryland, USA), p-AMPKα1(#2535, Cell Signaling, Maryland, USA), AMPKα1(SC-19128, Santa Cruz Biotechnology, California, USA), SIRT-1(SC-74465, Santa Cruz Biotechnology, California, USA), PGC-1α(AF-1817a, ABGENT, San Diego , USA ), PPAR-α(SC-9000, Santa Cruz Biotechnology, California, USA), SOD1(SC-8647, Santa Cruz Biotechnology, California, USA), Finally, the blots were hybridized with horseradish peroxidase-labeled secondary antibodies and pictures were then taken with Fujifilm LAS-3000 (GE healthcare UK limited., Buckinghamshire, UK).