Electrical pulse stimulation-induced muscle contraction alters the microRNA and mRNA profiles of circulating extracellular vesicles in mice.

Extracellular vesicles, such as exosomes, are secreted by skeletal muscle tissues and may play a role in physiological adaptations induced by exercise. Endurance exercise changes the microRNA (miRNA) profile of circulating extracellular vesicles; however, the effects of resistance exercise are unknown. In this study, we examined the effect of resistance exercise as electrical pulse stimulation (EPS)-induced muscle contraction on the miRNA and mRNA profiles of circulating extracellular vesicles in mice using a comprehensive RNA sequencing-based approach.

Icing after eccentric contraction-induced muscle damage perturbs the disappearance of necrotic muscle fibers and phenotypic dynamics of macrophages in mice.

Icing is still one of the most common treatments to acute skeletal muscle damage in sports medicine. However, previous studies using rodents reported the detrimental effect of icing on muscle regeneration following injury. This study aimed to elucidate the critical factors governing the impairment of muscle regeneration by icing with a murine model of eccentric contraction-induced muscle damage by electrical stimulation.

Alterations of macrophage and neutrophil content in skeletal muscle of aged versus young mice.

Background: Skeletal muscle inflammation and oxidative stress are associated with aging-related loss of muscle mass and may be attributable to alterations in the number and types of leukocytes in skeletal muscle. Here, we tested the hypothesis that aging changes the number and composition of leukocyte subsets in skeletal muscle tissue.

Methods: Skeletal muscle was sampled from 4-mo-old (young) and 27-mo-old (old) C57BL/6J mice.

Differential protective effects of Radix astragali, herbal medicine, on immobilization-induced atrophy of slow-twitch and fast-twitch muscles.

Radix astragali is a popular traditional herbal medicine that provides significant protection against tissue injury in various models of oxidative stress-related diseases. In this study, we aimed to investigate whether administration of Radix astragali prevented atrophy in both slow- and fast-twitch muscles following cast immobilization. Twenty-seven 12-week-old male F344 rats were divided into three experimental groups: control (CON), immobilized (IM), and immobilized with Radix astragali administration (IM+AR).

Exercise training suppresses scavenger receptor CD36 expression in kupffer cells of nonalcoholic steatohepatitis model mice.

Although nonalcoholic steatohepatitis (NASH) is an important component of the metabolic syndrome, scavenger receptor CD36 also modulates NASH development. This study aimed to clarify whether exercise training suppresses CD36 expression in a mouse model of NASH. Male C57BL/6 mice were divided into four groups: normal diet (ND) sedentary, ND exercise, high-fat diet and high-fructose water (HFF) sedentary, and HFF exercise groups.

Local cyclical compression modulates macrophage function and alleviates immobilization-induced muscle atrophy.

Physical inactivity gives rise to numerous diseases and organismal dysfunctions, particularly those related to aging. Musculoskeletal disorders including muscle atrophy, which can result from a sedentary lifestyle, aggravate locomotive malfunction and evoke a vicious circle leading to severe functional disruptions of vital organs such as the brain and cardiovascular system. Although the significance of physical activity is evident, molecular mechanisms behind its beneficial effects are poorly understood.

Effects of aging on serum levels of lipid molecular species as determined by lipidomics analysis in Japanese men and women.

Background: Aging is known to be associated with increased risk of lipid disorders related to the development of type 2 diabetes. Recent evidence revealed that change of lipid molecule species in blood is associated with the risk of type 2 diabetes. However, changes in lipid molecular species induced by aging are still unknown.

Endurance exercise training and high-fat diet differentially affect composition of diacylglycerol molecular species in rat skeletal muscle.

Insulin resistance of peripheral muscle is implicated in the etiology of metabolic syndrome in obesity. Although accumulation of glycerolipids, such as triacylglycerol and diacylglycerol (DAG), in muscle contributes to insulin resistance in obese individuals, endurance-trained athletes also have higher glycerolipid levels but normal insulin sensitivity. We hypothesized that the difference in insulin sensitivity of skeletal muscle between athletes and obese individuals stems from changes in fatty acid composition of accumulated lipids.

Time-course study of macrophage infiltration and inflammation in cast immobilization-induced atrophied muscle of mice.

Introduction: Macrophage infiltration may play an important role in mediating the development of muscle atrophy. However, temporal differences in the activation of muscle atrophy signaling pathways and the progress of macrophage infiltration during the atrophic phases of cast immobilization are currently unknown.

Methods: C57BL/6J mice were euthanized after cast immobilization at 1, 3, 7, and 14 days.

TLR4-defective (C3H/HeJ) mice are not protected from cast immobilization-induced muscle atrophy.

Recent studies have shown that activation of Toll-like receptor (TLR)4 signaling may be an important factor in muscle atrophy and excessive inflammatory response associated with immobilization. To examine the role of TLR4 signaling on cast immobilization-induced skeletal muscle atrophy, we tested the hypothesis that muscle atrophy and inflammation after cast immobilization is reduced in TLR4-defective mice. TLR4-defective (C3H/HeJ) and wild type (C3H/HeN) mice were divided into control and cast-immobilization groups.

Abnormal lipid/lipoprotein metabolism and high plasma testosterone levels in male but not female aromatase-knockout mice.

Sex steroid hormones, such as estrogen and testosterone, are believed to play important roles in lipid metabolism. To elucidate the effects of estrogen depletion on lipid metabolism in male and female mice, we used aromatase-knockout (ArKO) mice, in which Cyp19 gene disruption prevented estrogen synthesis in vivo. These mice were divided into the following 4 groups: male and female ArKO mice and male and female wild-type (WT) mice.

Neutrophil Depletion Attenuates Muscle Injury after Exhaustive Exercise.

Purpose: The infiltration of macrophages in skeletal muscle during exhaustive exercise promotes inflammation, myofiber lesion, and muscle injury. Although neutrophils upregulate macrophage infiltration in skeletal muscles during exercise, the role of neutrophils in promoting muscle injury after exhaustive exercise remains unclear. In this study, we investigated the effects of preexercise neutrophil depletion with antineutrophil antibody treatment on muscle injury, inflammation, and macrophage infiltration after exhaustive exercise.

Macrophage depletion by clodronate liposome attenuates muscle injury and inflammation following exhaustive exercise.

Exhaustive exercise promotes muscle injury, including myofiber lesions; however, its exact mechanism has not yet been elucidated. In this study, we tested the hypothesis that macrophage depletion by pretreatment with clodronate liposomes alters muscle injury and inflammation following exhaustive exercise. Male C57BL/6J mice were divided into four groups: rest plus control liposome (=8), rest plus clodronate liposome (=8), exhaustive exercise plus control liposome (=8), and exhaustive exercise plus clodronate liposome (=8).

Exercise training attenuates neutrophil infiltration and elastase expression in adipose tissue of high-fat-diet-induced obese mice.

The innate immune system is associated with the development of local inflammation. Neutrophils play an essential role in the development of the adipose tissue (AT) inflammation associated with obesity by producing elastase, which can promote the activation and infiltration of macrophages. Exercise training attenuates AT inflammation via suppression of macrophage infiltration.

Low-volume walking program improves cardiovascular-related health in older adults.

Although numerous sources of evidence show that regular physical activity is beneficial to health, most individuals do not engage in a sufficient amount of physical activity to meet the guidelines set out by expert panels. In addition, the minimum amount of physical activity associated with reduced cardiovascular disease risk markers is not clear in older adults. The purpose of this study was to determine the effects of a 12-week walking program involving an exercise volume below the current minimum physical activity recommendation on cardiovascular disease risk markers in older adults.

Low-volume exercise training and vitamin E supplementation attenuates oxidative stress in postmenopausal women.

The purpose of this study was to investigate the effects of low-volume exercise training (90 min/wk) and vitamin E supplementation on oxidative stress markers in postmenopausal women. The participants were non-randomly assigned the following four groups: control (C, n=8), vitamin E (S, n=8), exercise (Ex, n=6), or vitamin E and exercise (S+Ex, n=7). The S and S+Ex groups were instructed to take vitamin E (α-tocopherol, 300 mg/d) capsules for 12 wk.

Exhaustive exercise increases the TNF-α production in response to flagellin via the upregulation of toll-like receptor 5 in the large intestine in mice.

Although intense exercise may induce temporary immune depression, it is unclear whether exercise stimulates tumor necrosis factor-alpha (TNF-α) production in response to flagella protein flagellin (FG), which binds to toll-like receptor 5 (TLR5) and induces the production of pro-inflammatory cytokines. Male C3H/HeN mice were administered FG (1mg/kg, i.v.

Curcumin attenuates oxidative stress following downhill running-induced muscle damage.

Downhill running causes muscle damage, and induces oxidative stress and inflammatory reaction. Recently, it is shown that curcumin possesses anti-oxidant and anti-inflammatory potentials. Interestingly, curcumin reduces inflammatory cytokine concentrations in skeletal muscle after downhill running of mice.

Exercise training attenuates adipose tissue fibrosis in diet-induced obese mice.

Tissue fibrosis, such as that which occurs in obesity, is associated with chronic inflammatory diseases. Although regular exercise reduces adipose tissue inflammation, the mechanisms regulating the effects of exercise on adipose tissue fibrosis are unclear. This study aimed to clarify whether exercise training attenuates adipose tissue fibrosis with consequent reduction of extracellular matrix including collagens.

Exercise attenuates M1 macrophages and CD8+ T cells in the adipose tissue of obese mice.

Purpose: Obesity is associated with adipose tissue inflammation, which has been attributed to changes in the number and types of leukocytes in adipose tissue. Exercise training is thought to be important for the reduction of adipose tissue inflammation, but the mechanisms by which this may occur are incompletely understood. Here, we evaluated the effect of exercise training on several inflammation-associated changes in adipose tissue, including infiltration of inflammatory macrophages and T cells.

Effects of low-volume walking programme and vitamin E supplementation on oxidative damage and health-related variables in healthy older adults.

Background: Both exercise and vitamin E supplementation have been shown to reduce oxidative stress and cardiovascular disease risk in older adults, and when combined there is evidence suggesting that they act synergistically. The currently recommended amount of exercise for older adults is 150 min/week of moderate-intensity exercise; however, the minimum amount of exercise necessary to achieve health benefits is not known. The purpose of this study was to investigate the effects of 12 weeks of participation in a low-volume walking exercise programme (i.

Low-volume exercise training attenuates oxidative stress and neutrophils activation in older adults.

The purpose of this study was to investigate the effects of low-volume exercise training (100 min/week) on oxidative stress and neutrophils activation markers in older adults. Twenty-eight older adults (age range 65-78 years) were assigned into control (n = 14) or exercise (n = 14) groups. The exercise program consisted of walking 30-60 min/session, 2 days each week for 12 weeks.

Exercise training inhibits inflammation in adipose tissue via both suppression of macrophage infiltration and acceleration of phenotypic switching from M1 to M2 macrophages in high-fat-diet-induced obese mice.

Purpose: Recent studies suggest that exchange of macrophage phenotype (M1/M2) in adipose tissue is associated with chronic low-grade inflammation in obesity. M1 macrophages enhance a chronic inflammatory state in adipose tissues, whereas M2 macrophages inhibit it. Although exercise training might inhibit pro-inflammatory cytokine gene expression in adipose tissue, it remains unclear whether exercise training affects the phenotypic switch of macrophage polarization in adipose tissue.

Exhaustive exercise reduces TNF-α and IFN-α production in response to R-848 via toll-like receptor 7 in mice.

Stressful exercise results in temporary immune depression. However, the impact of exercise on the immune responses via toll-like receptor (TLR) 7, which recognizes the common viral genomic feature, single-stranded RNA, remains unclear. To clarify the effect of stressful exercise on immune function in response to viral infection, we measured the changes in the plasma concentration of tumor necrosis factor (TNF)-α and interferon (IFN)-α, which are induced downstream from the TLR-ligand interaction, in exhaustive-exercised mice immediately after treatment with the imidazoquinoline R-848, which can bind to and activate TLR7.