Impact of a single bout of high-intensity interval exercise and short-term interval training on interleukin-6, FNDC5, and METRNL mRNA expression in human skeletal muscle

Abstract

BackgroundExercise promotes numerous phenotypic adaptations in skeletal muscle that contribute to improved function and metabolic capacity. An emerging body of evidence suggests that skeletal muscle also releases a myriad of factors during exercise, termed “myokines”. The purpose of this study was to examine the effects of high-intensity interval training (HIIT) on the acute regulation of the mRNA expression of several myokines, including the prototypical myokine interleukin-6 (IL-6), and recently identified myokines fibronectin type III domain-containing protein 5 (FNDC5) (irisin) and meteorin-like protein (METRNL).MethodsBoth before and after a 20-day period of twice-daily high-volume HIIT, 9 healthy males (20.5 ± 1.5 years performed a standardized bout of high-intensity interval exercise (HIIE; 5 × 4 min at ~80% pretraining peak power output) with skeletal muscle biopsy samples (vastus lateralis) obtained at rest, immediately following exercise, and at 3 h recovery.ResultsBefore training, a single bout of HIIE increased IL-6 (p < 0.05) and METRNL (p < 0.05) mRNA expression measured at 3 h recovery when compared to rest. Following 20 days of HIIT, IL-6 and FNDC5 mRNA were increased at 3 h recovery from the standardized HIIE bout when compared to rest (both p < 0.05). Resting METRNL and FNDC5 mRNA expression were higher following training (p < 0.05), and there was an overall increase in FNDC5 mRNA post-training (main effect of training, p < 0.05).ConclusionIn human skeletal muscle (1) an acute bout of HIIE can induce upregulation of skeletal muscle IL-6 mRNA both before and after a period of intensified HIIT; (2) Resting and overall FNDC5 mRNA expression is increased by 20 days of HIIT; and (3) METRNL mRNA expression is responsive to both acute HIIE and short-term intense HIIT. Future studies are needed to confirm these findings at the protein and secretion level in humans.

Myokines in skeletal muscle physiology and metabolism: Recent advances and future perspectives

“…91 The role of METRNL in alleviating insulin resistance and lipid-mediated inflammation in skeletal muscle via AMP-activated protein kinase (AMPK) or peroxisome proliferator-activated receptor δ (PPARδ) has recently been investigated. 93 Taken together, these studies suggest that METRNL may offer exercise-mediated protection against metabolic disorders. 92 Furthermore, METRNL administration rescued glucose intolerance and reduced HFD-induced body weight gain in mice without affecting caloric intake.…”

“…92 Supporting evidence has shown METRNL mRNA expression was increased in the resting state after 20 days of short-term high-volume high-intensity interval training (HIIT), and HIIT resulted in the elevated levels of potential fat browning myokines in skeletal muscle. 93 Taken together, these studies suggest that METRNL may offer exercise-mediated protection against metabolic disorders.…”

Forty high-intensity interval training sessions blunt exercise-induced changes in the nuclear protein content of PGC-1α and p53 in human skeletal muscle

“…Total RNA was isolated from ∼15 mg of muscle tissue as previously described (14). Briefly, samples were homogenized (FastPrep FP120 Homogenizer; Thermo Savant) in the presence of 1 g of zirconia/silica beads (1.0 mm; Daintree Scientific, St. Helens, TAS, Australia) and 800 μL of TRIzol® Reagent (Invitrogen, Melbourne, Australia).…”

Será a combinação dos treinamentos intervalado e resistido mais efetiva sobre a aptidão física em adultos? Uma revisão sistemática e metanálise

“…This method is characterized by intense loads of exercise separated by a period of interval between series 9 , with adaptive benefits superior to other types of training such as continuous aerobic exercise, but with less training volume 10 . In addition, this training protocol has helped to achieve greater adherence to exercise programs, precisely because it presents an efficient dose of time and reduces the health risks associated with obesity 11 . Among the methodologies observed in the various studies that use the principles of interval training, sprint interval training (SIT) is defined as sprints of short duration (8 to 30 seconds), with intensity greater than 100% of VO 2max and interspersed with recovery periods 8 , while high-intensity interval training (HIIT) is characterized by exercise sessions with intensities between 80% and 100% of maximum heart rate or aerobic capacity, with duration between 60 and 240 seconds, which are within the aerobic capacity of the individual (sub-maximum), but extremely intense 9 .…”

“…In addition, this protocol produces the EPOC effect (excessive post-exercise oxygen consumption), and through this system, brings long-term benefits to individuals by increasing basal metabolic rate and caloric expenditure and improves lipid oxidation 14 . Although there is consensus in literature about the benefits of interval and resistance training alone, it is important to analyze the effectiveness of the combination of these two protocols, since the sum of benefits brought by both seems to be an interesting strategy to improve the physical fitness indicators, weight management and health enrichment in adults 11,7 . Therefore, the aim of this meta-analysis is to compare the effectiveness of combined training (HIIT / SIT + RT) with other exercise protocols on HRPF indicators in adults.…”