Dietary Supplementation With Montmorency Tart Cherries and Exercise Improves Lean Mass in Older C57BL/6 Mice

Abstract

Objectives: Sarcopenia, the progressive loss of muscle mass and strength, accelerates with age. Current recommendations to prevent sarcopenia focus on exercise and protein intake. Tart cherry (TC) has shown beneficial effects on muscle recovery following exercise. In this study, we investigated the effects of TC alone and in combination with exercise on lean mass, mitochondrial biogenesis, and oxidative stress in young compared to older mice. Methods: In two cohorts (6 & 52 wk-old), female C57BL/6 mice were randomly assigned to 4 groups in a 2 × 2 factorial design with diet (AIN-93 control or TC supplemented at 10% w/w) and exercise as factors. Exercise consisted of treadmill running for 30 min, 5 d/wk, at 12 m/min and a 5° incline. Food intake was recorded daily and body weights weekly. After 8 wks, body composition was assessed using dual-energy x-ray absorptiometry. The gastrocnemius muscle was collected for protein analysis. Western blotting techniques were used to probe for superoxide dismutase 2 (SOD2) and peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1a), indicators of oxidative stress and mitochondrial biogenesis. Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was used as loading control. Data were analyzed using 2-way ANOVA with α = 0.05. Results: In young mice, TC had no effect on body weight and % lean mass, but led to decreased (P < 0.05) % fat mass compared to controls. Exercise decreased (P < 0.05) body weight and % fat, and tended to increase (P = 0.069) % lean mass. In contrast, TC and exercise independently decreased body weight and % fat, and increased % lean mass in older mice compared to controls. The combination of TC and exercise tended to have a synergistic effect on % lean mass (P = 0.056). Preliminary results show that TC significantly up-regulated SOD2 protein expression in young mice, but no effect was observed with exercise or combined treatments. PGC1α expression tended to be suppressed (P = 0.064) in young animals fed TC. To date, we have been unable to detect changes in SOD2 and PGC1α in older mice. Conclusions: TC had a protective effect on lean tissue in older mice, preliminary analyses revealed no alterations in oxidative stress or mitochondrial biogenesis. Further investigation is warranted to understand the benefits of TC on lean muscle mass in older mice.