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C-31 Free Communication/Poster - Fat Metabolism Thursday, June 2, 2016, 7: 30 AM - 12: 30 PM Room: Exhibit Hall A/B

Time Course Of Changes In Skeletal Muscle Mitochondrial Proteins After Cessation Of High-fat Diet Feeding

1446 Board #99 June 2, 9

00 AM - 10

30 AM

Li, Xi; Higashida, Kazuhiko; Higuchi, Mitsuru FACSM

Author Information
Medicine & Science in Sports & Exercise: May 2016 - Volume 48 - Issue 5S - p 387
doi: 10.1249/01.mss.0000486171.16426.dd
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High fat diet (HFD) feeding induces an increase in mitochondrial biogenesis in skeletal muscle. However, time course of changes in the increased mitochondrial proteins by HFD feeding to the baseline level after cessation of HFD feeding are not known.

PURPOSE: To investigate the time course changes of skeletal muscle mitochondrial proteins after cessation of HFD feeding.

METHODS: Five-week-old male C57BL/6 mice (n=32) were divided into control diet (CON, n=8) and high-fat diet (HFD, n=24) groups. HFD group was fed a HFD for 4 weeks, and then divided into three subgroups, HFD+0, HFD+3, HFD+7. Mice in HFD+0 group were sacrificed immediately after HFD intervention, whereas HFD+3 and HFD+7 groups were killed after switching from HFD to control diet 3 and 7 days, respectively. Gastrocnemius muscles were dissected out for measurement of electron transport chain proteins (COXI, COXV) as well as long chain acyl CoA dehydrogenase (LCAD). Plantaris muscles were used for the mitochondrial DNA copy number measurement.

RESULTS: The protein expression of COXIand COXVwere significantly higher in HFD+0 group compared to CON group(P=0.038, P=0.037), whereas those of HFD+3 and HFD+7 group were not different from CON group. In contrast to electron transport chain proteins, the LCAD protein expression in HFD+0 and HFD+3 groups showed significant increases compared to CON group(P=0.046, P=0.005). Mitochondrial DNA copy numbers in all HFD groups were significantly increased (P=0.000, P=0.000, P=0.002), but did not return to CON even 7 days after cessation of HFD.

CONCLUSION: These results suggested that the electron transport chain proteins decline rapidly, whereas enzyme involved in β-oxidation returns slowly after cessation of HFD feeding. Furthermore, elevated mitochondrial DNA copy number persists at least 1 week after cessation of HFD feeding.

© 2016 American College of Sports Medicine