BackgroundDoxorubicin, a widely used anti‐tumour drug, is known to cause muscle loss in cancer patients.MethodsFollowing an acute dose of doxorubicin injection (2.5 mg/kg per body weight), we examined macrophage distribution in rat soleus muscle challenged by eccentric exercise (downhill running). Long‐term doxorubicin treatment (one injection every 3 days) on muscle mass and survival were also determined.ResultsUnder non‐exercised condition, increased tumour necrosis factor (TNF)‐alpha mRNA and decreased IL‐10 mRNA were observed in soleus muscle of doxorubicin‐treated rats, compared with saline‐treated control rats. However, increases in inflammation score (leukocyte infiltration), nitrotyrosine level, and M1 macrophage (CD68+) invasion in exercised soleus muscle were absent in doxorubicin‐treated rats, whereas increased M2 macrophage (CD163+) localization in exercised muscle was less affected by doxorubicin. Despites coenzyme Q (Q10) supplementation significantly elevated TNF‐alpha mRNA, nitrotyrosine, and anti‐oxidant gamma‐glutamylcysteine synthetase (GCS) levels in non‐exercised soleus muscle, these pro‐inflammatory responses were also abolished in doxorubicin‐treated rats. Results from long‐term doxorubicin treatment show a significant muscle loss followed by an accelerated death, which cannot be reversed by Q10 supplementation.Conclusions(i) Doxorubicin impairs inflammation mechanism by depleting M1 macrophage in exercised skeletal muscle; (ii) Muscle loss and accelerated death during prolonged doxorubicin treatment cannot be reversed by Q10 supplementation.

BackgroundGinsenoside Rg1 has been shown to clear senescence-associated beta-galactosidase (SA-β-gal) in cultured cells. It remains unknown whether Rg1 can influence SA-β-gal in exercising human skeletal muscle.MethodsTo examine SA-β-gal change, 12 young men (age 21 ± 0.2 years) were enrolled in a randomized double-blind placebo controlled crossover study, under two occasions: placebo (PLA) and Rg1 (5 mg) supplementations 1 h prior to a high-intensity cycling (70% VO2max). Muscle samples were collected by multiple biopsies before and after cycling exercise (0 h and 3 h). To avoid potential effect of muscle biopsy on performance assessment, cycling time to exhaustion test (80% VO2max) was conducted on another 12 participants (age 23 ± 0.5 years) with the same experimental design.ResultsNo changes of SA-β-gal were observed after cycling in the PLA trial. On the contrary, nine of the 12 participants showed complete elimination of SA-β-gal in exercised muscle after cycling in the Rg1 trial (p < 0.05). Increases in apoptotic DNA fragmentation (PLA: +87% vs. Rg1: +133%, p < 0.05) and CD68+ (PLA: +78% vs. Rg1: +121%, p = 0.17) occurred immediately after cycling in both trials. During the 3-h recovery, reverses in apoptotic nuclei content (PLA: +5% vs. Rg1: −32%, p < 0.01) and increases in inducible nitrate oxide synthase and interleukin 6 mRNA levels of exercised muscle were observed only in the Rg1 trial (p < 0.01).ConclusionRg1 supplementation effectively eliminates senescent cells in exercising human skeletal muscle and improves high-intensity endurance performance.

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Background: We have previously shown an accelerated recovery from muscle fatigue in men challenged by prolonged exercise after oral deep ocean minerals (DOM) supplementation. Here, we hypothesized a decrease in eccentric exercise-induced muscle inflammation in rats regularly consuming DOM-containing drinks (hardness 600 mg/L and fructose 11%).Methods: Forty-seven male Sprague Dawley rats were randomized into 4 groups: Control (C, N = 12), Fructose (F, N = 12), Fructose+Exercise (FE, N = 12), and Fructose+Exercise+DOM (FED, N = 11). Since fructose is a commonly used ingredient in beverages, 11% of fructose was added as a vehicle of the study. Soleus muscles of rats were analyzed 24 h after an acute bout of downhill running following 9 weeks of DOM supplementation.Results: Leukocyte infiltration and TNF-α mRNA of muscle in the FE group were 5 times and 4 times greater the F group, respectively, (P < 0.05). Both markers in the FED group were significantly lower than those in the FE group (P < 0.05). IL-10 mRNA of muscle in the F group was >eight fold greater than the C group (P < 0.05). The reduced glutathione (GSH) of muscle in the F group was 34% lower than that in the C group (P < 0.05). However, GSH levels were similar for the C and FED groups.Conclusion: Prolonged fructose supplementation modulates inflammatory balance of rat skeletal muscle. The results of the study suggest that DOM can minimize eccentric exercise-induced inflammatory cytokine responses in rat skeletal muscle.

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