Effects of 2-week HMB-FA supplementation with or without eccentric resistance exercise on expression of some genes related to muscle protein turnover and serum irisin and IGF-1 concentrations

• Published in: Gene 2020-11, Vol.760, p.145018-145018, Article 145018
• Main Authors: Shirvani, Hossein, Rahmati-Ahmadabad, Saleh, Kowsari, Elias, Fry, Hillary, Kazemi, Maryam, Kaviani, Mojtaba
• Format: Article
• Language: English
• Subjects: Atrophy; Caspase; Hypertrophy; Leucine; Myostatin; Resistance training
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2020.145018

•Eccentric resistance exercise, HMB-FA supplement, and their interaction enhanced serum irisin concentration.•Triceps brachii muscle myostatin gene expression was decreased in response to eccentric resistance exercise.•HMB-FA might have a suppressing effect on caspase-9 and consequently caspase-3. Protein turnover is a process that is regulated by several factors and can lead to muscle hypertrophy or atrophy. The purpose of the present study was to determine the effects of β-hydroxy-β-methylbutyrate free acid (HMB-FA) and eccentric resistance exercise on variables related to protein turnover in rats. Thirty-two male rats were randomly assigned into four groups of eight, including control, control-HMB, exercise, and exercise-HMB. Animals in HMB groups received 340 mg/kg/day for two weeks. Animals in the exercise groups performed one session of eccentric resistance exercise consisting of eight repetitions descending from a ladder with a slope of 80 degree, with an extra load of two times body weight (100% 1RM). Twenty-four hours after the exercise session, triceps brachii muscle and serum were collected for further analysis. Exercise and HMB-FA induced lower muscle myostatin and higher muscle Fibronectin type III domain containing 5 (FNDC5), P70-S6 kinase 1 gene expression, as well as higher serum irisin and IGF-1 concentrations. Exercise alone induced higher caspase-3 and caspase-8 gene expression while HMB-FA alone induced lower caspase 3 gene expression. HMB-FA supplement increased the effect of exercise on muscle FNDC5, myostatin, and P70-S6 kinase 1 gene expression. The interaction of exercise and HMBFA resulted in an additive effect, increasing serum irisin and IGF-1 concentrations. In conclusion, a 2-week HMB-FA supplementation paired with acute eccentric resistance exercise can positively affect some genes related to muscle protein turnover.