Differential metabolic effects of constant moderate versus high intensity interval training in high-fat fed mice: possible role of muscle adiponectin

Abstract

Exercise regimens may have differing effects in the presence of obesity. In addition to being fat derived, adiponectin has recently been described as a myokine that regulates insulin sensitivity, which may link to exercise‐related metabolic benefits in obesity. Whether skeletal muscle adiponectin varies in different exercise modalities is unclear. This study investigated the comparative effects of 10 weeks of endurance constant‐moderate intensity exercise (END) with high intensity interval training (HIIT), on metabolic outcomes, including muscle adiponectin in a mouse model of diet‐induced obesity. Ten‐week‐old male C57BL/6 mice were fed a high‐fat diet (HFD) (45% FAT) or standard CHOW diet ab libitum and underwent one of three training regimes: (1) no exercise, (2) END, or (3) HIIT (8 bouts of 2.5 min with eight periods of rest of 2.5 min) for 10 weeks (3 × 40 min sessions/week). Chow‐fed mice acted as controls. Compared with HFD alone, both training programs similarly protected against body weight gain (HFD = 45 ± 2; END = 37 ± 2; HIIT = 36 ± 2 g), preserved lean/fat tissue mass ratio (HFD = 0.64 ± 0.09; END = 0.34 ± 0.13; HIIT = 0.33 ± 0.13), and improved blood glucose excursion during an insulin tolerance test (HFD = 411 ± 54; END = 350 ± 57; HIIT = 320 ± 66 arbitrary units [AU]). Alterations in fasting glycemia, insulinemia, and AST/ALT ratios were prevented only by END. END, but not HIIT increased skeletal muscle adiponectin mRNA (14‐fold; P < 0.05) and increased protein content of high molecular weight (HMW) adiponectin (3.3‐fold), whereas HIIT induced a milder increase (2.4‐fold). Compared with HFD, neither END nor HIIT altered circulating low (LMW) or high (HMW) molecular weight adiponectin forms. Furthermore, only END prevented the HFD downregulation of PGC1α (P < 0.05) mRNA levels downstream of muscle adiponectin. These data show that different training programs affect muscle adiponectin to differing degrees. Together these results suggest that END is a more effective regimen to prevent HFD‐induced metabolic disturbances in mice.

Skeletal muscle adiponectin induction depends on diet, muscle type/activity, and exercise modality in C57BL/6 mice

“…Simultaneously, each dietary group was then randomized to either constant moderate‐intensity endurance (END) or high‐intensity interval training (HIIT), as previously described (Martinez‐Huenchullan et al. ). Untrained animals fed either the Chow or HFD acted as controls.…”

“…The quadriceps data presented here, as previously stated, has been published in a previous issue of Physiological Reports (Martinez‐Huenchullan et al. ), and it is included here for the sole purpose of facilitating the comparisons between the three muscles.…”

“…The study was approved by the University of Sydney Animal Ethics Committee (Protocol #2015/816). Moreover, this study shares the same ethics approval as a previously published study (Martinez-Huenchullan et al 2018) and were carried out according to the guidelines and conform to the principles and regulations, as described in the Editorial (Grundy 2015).…”

“…Given that exercise is one of the life-style modifications proposed to counteract these pathological disturbances, our group investigated the effect of different exercise programs on quadriceps muscle adiponectin profiles in high-fat fed mice. We found that 10 weeks of constant-moderate intensity training resulted in better metabolic systemic effects which were associated with a greater increase in the most bioactive muscle adiponectin isoform (highmolecular weight (HMW)) compared with high-intensity interval training (Martinez-Huenchullan et al 2018). However, as adiponectin induction in skeletal muscles may be dependent on fiber type (Krause et al 2008), and that the muscle group analyzed (quadriceps) was composed of a mixture of glycolytic and oxidative fibers (Jacobs et al 2013), the characteristics of adiponectin induction derived from exercise between muscles with different metabolic profiles, requires exploration.…”

“…We found that 10 weeks of constant‐moderate intensity training resulted in better metabolic systemic effects which were associated with a greater increase in the most bioactive muscle adiponectin isoform (high‐molecular weight (HMW)) compared with high‐intensity interval training (Martinez‐Huenchullan et al. ). However, as adiponectin induction in skeletal muscles may be dependent on fiber type (Krause et al.…”