The effect of voluntary exercise training on LPS-induced TNF-alpha after exhaustive exercise

OBJECTIVES: Acute strenuous exercise attenuates inflammatory cytokine production. The attenuation after strenuous exercise is due to the effect of catecholamine. Voluntary exercise training has many beneficial effects, for example enhanced immune function at rest. However, little is known that the influence of voluntary exercise training on pro-inflammatory cytokine in response to pathogen. In this study, we investigated the effect of voluntary exercise training on production of tumor necrosis factor (TNF)-alpha in response to lipopolysaccharide (LPS) after strenuous exercise. METHODS: Female F344 rats were divided into two groups, voluntary training and sedentary. The voluntary trained rats engaged in wheel running for 10 weeks, while the sedentary rats remained in their cages. After 10 weeks, all rats were treated an exhaustive exercise or a rest for 2 h. The exhaustive exercise was a treadmill running exercise until exhaustion. To measure catecholamine and TNF-alpha concentrations, and TNF-alpha mRNA expression in tissue in response to LPS, the rats received an injection of LPS and were killed 1 h after the LPS injection. RESULTS: Running time until exhaustion in voluntary trained rats was significantly longer than that in sedentary rats (p\u3c0.01). Plasma adrenaline after exhaustive exercise was significantly higher than that in sedentary rats (p\u3c0.01). LPS-induced TNF-alpha concentration in plasma significantly differs by presence or absence of voluntary training and exhaustive exercise (p\u3c0.01, respectively). Although voluntary training significantly reduced the protein content of TNF-alpha in kidney at rest (p\u3c0.05), exhaustive exercise did not affect TNF-alpha in response to LPS in kidney. Also, neither the exhaustive exercise did affect in mRNA expression of TNF-alpha in kidney in trained rats. CONCLUSION: These results suggest that voluntary exercise training may have little effect on the improvement of TNF-alpha response after exhaustive exercise, although voluntary training has a role in reducing LPS-induced TNF-alpha contenet at rest in kidney

Relationship Between Macrophage Differentiation And The Chemotactic Activity Toward Damaged Muscle Cells

Aim: We investigated the effect of macrophage differentiation on the chemotactic activity to invade local damaged muscle using in vitro models of muscle injury. Methods: C2C12 cell myoblasts, and J774 cell macrophages were used. The “killed-C2C12” cells were combined with live C2C12 cells (live:killed C2C12 = 1:0.5) as a partially damaged muscle model. The J774 cells were stimulated with LPS and DEX. The chemotactic activity of J774 cells was examined using TAXIScan device. Results: Although the velocity of J774 cells was little affected by each type of C2C12 cells (live, killed and combination), the directionality of the J774 cells was increased. The highest directionality of J774 cells was observed when the ratio of live-:killed-C2C12 cells was 1:0.5.The TLR4 and CD11c expressions of LPS cells were higher than those in both Ctrl and DEX cells. The LPS cells were strongly stained around the cell membrane by phalloidin, but the F-actin expression in DEX cells was in an orderly line along the long axis of cells. DEX cells showed stretching toward C2C12 cells, and their length/width ratio was higher than that in both Ctrl and LPS cells. Although the chemotactic activity of LPS cells disappeared completely, DEX cells exhibited accelerated chemotactic activity toward damaged muscle cells. The MCP-1 production in live-:killed-C2C12 cells was higher than that in the live-C2C12 cells. The CCR2 expression in DEX cells was higher than that in both Ctrl and LPS cells. Conclusion: Our conclusion is that: 1) the chemotactic activity of macrophages toward areas of damaged muscle induces more live myoblasts than damaged cells, 2) the chemotactic activity of macrophages is not due to velocity, but depends on the directionality toward damaged muscle cells, and 3) macrophage differentiation influences their chemotactic activity toward damaged muscle cells through the expression of CCR2 and/or F-actin

Exhaustive Exercise Enhances Immune Response To Flagellin Via Adrenaline-Mediated Up-Regulation of TLR5 Expression

Objective: We already reported that lipopolysacchride (LPS)-induced tumor necrosis factor (TNF)-α production as a bacterial infection model to induce immune response, was inhibited by exhaustive exercise. However, it remains unclear whether or not the immune response to flagellin (FG), which binds to toll like receptor 5(TLR5) and induces pro-inflammatory cytokine production, is also inhibited by this severe exercise. The aim of this study was to determine whether or not exhaustive exercise affects TNF-α productions after FG injection in mice. Methods: Both exhaustive-exercised (EX; n=12) and non-exercised (N-EX; n=12) male C3H/HeN mice were injected with FG (1 mg/kg, i.v), and blood samples were collected. In addition, to clarify the effect of catecholamine on immune response macrophage and intestinal cells after FG stimulation, RAW264 cells and Caco2 cells were cultured 30min after propranolol (Prop; β-adrenergic receptors blocker) or Ly294002 (Ly; PI3K inhibitor) treatments, and were then stimulated with adrenaline (AD; 1 μM) and FG (5 μg/ml). Moreover, the effect of Prop (10 mg/kg, n=12) on FG-induced TNF-α production in EX mice was also examined. Results: TNF-α in EX group was significantly higher than that in N-EX group after FG injection. In epithelium cells, more intensity of TLR5 localization was observed on the plasma membrane area than in the cytosol area in EX mice, but not N-EX mice. Caco2 cells, but not RAW264 cells, significantly increased the FG-induced TNF-α production using AD treatment. Moreover, Prop treatment attenuated the AD-induced TNF-α production in response to FG in Caco2 cells. Although TLR5 expression on RAW264 cells was significantly decreased after AD treatment, the expression on Caco2 cells was rapidly increased. In fact, we observed the AD-dependent TLR5 translocation from cytoplasm to cell membrane in Caco2 cells, and the membrane translocation was inhibited by Prop and Ly treatment. Moreover, the pretreatment with Prop attenuated the exercise-induced plasma TNF-α response to FG in vivo. Conclusion: Our results suggest that immune response to FG via TLR5 might be enhanced by exhaustive exercise in mice

Reduction of Real-Time Imaging of M1 Macrophage Chemotaxis toward Damaged Muscle Cells is PI3K-Dependent

Macrophages migrate and invade into damaged muscle rapidly and are important for muscle repair and subsequent regeneration. The exact cellular and biological events that cause macrophage migration toward injured muscle are not completely understood. In this study, the effect of macrophage differentiation on the chemotactic capability to invade local damaged muscle was investigated using an in vitro model of muscle injury. We used C2C12 cell myoblasts and J774 cell macrophages, and the “killed-C2C12” cells were combined with live C2C12 cells as a partially damaged muscle model. The cultured J774 cells, with or without lipopolysaccharide (LPS), were treated with Ly294002 (Ly), which is an inhibitor of phosphoinositide 3-kinase (PI3K). In order to evaluate the polarization effect of LPS stimulation on J774 cells, expression of cell surface Toll-like receptor 4 (TLR4), CD11c and CCR2, and expression of F-actin intensity, were analyzed by flow cytometry. The real-time horizontal chemotaxis assay of J774 cells was tested using the TAXIScan device. The expressions of TLR4, CD11c, and F-actin intensity in LPS-treated cells were significantly higher than those in Ctrl cells. In LPS-treated cells, the chemotactic activity toward damaged muscle cells completely disappeared. Moreover, the reduced chemotaxis depended far more on directionality than velocity. However, Ly treatment reversed the reduced chemotactic activity of the LPS-treated cells. In addition, cell-adhesion and F-actin intensity, but not CCR2 expression, in LPS-treated cells, was significantly reduced by Ly treatment. Taken together, our results suggest that the PI3K/Akt activation state drives migration behavior towards damaged muscle cells

The Effect of Voluntary Exercise on Gut Microbiota in Partially Hydrolyzed Guar Gum Intake Mice under High-Fat Diet Feeding

Although dietary fiber treatment alters the gut microbiota and its metabolite production, it is unclear whether or not exercise habits can have a supplemental effect on changes in gut microbiota in dietary fiber-treated mice. To clarify the supplemental effect of voluntary exercise on gut microbiota in partially hydrolyzed guar gum (PHGG), which is a soluble dietary fiber, treated mice under high-fat diet (HFD) feeding, 4-week-old male C57BL/6J mice (n = 80) were randomly divided into two dietary groups: the control-diet (CD) and HFD. Then, each dietary group was treated with or without PHGG, and with or without wheel running. After the experimental period, measurement of maximal oxygen consumption, a glucose tolerance test and fecal materials collection for analysis of gut microbiota were carried out. Voluntary exercise load in PHGG treatment under HFD feeding showed the supplemental effect of exercise on obesity (p < 0.01) and glucose tolerance (p < 0.01). Additionally, in both CD and HFD groups, voluntary exercise accelerated the decrease in the Firmicutes/Bacteroidetes ratio in mice fed with PHGG (p < 0.01). These findings suggest that voluntary exercise might activate the prevention of obesity and insulin resistance more via change in gut microbiota in mice administrated with PHGG