Beneficial Effects and Potential Mechanisms of Tai Chi on Lower Limb Osteoarthritis: A Biopsychosocial Perspective / 中国结合医学杂志

Lower limb osteoarthritis (OA) is a chronic, multifactorial disease characterized by impaired physical function, chronic pain, compromised psychological health and decreased social functioning. Chronic inflammation plays a critical role in the pathophysiology of OA. Tai Chi is a type of classical mind-body exercise derived from ancient Chinese martial arts. Evidence supports that Tai Chi has significant benefits for relieving lower limb OA symptoms. Using a biopsychosocial framework, this review aims to elucidate the beneficial effects of Tai Chi in lower limb OA and disentangle its potential mechanisms from the perspective of biology, psychology, and social factors. Complex biomechanical, biochemical, neurological, psychological, and social mechanisms, including strengthening of muscles, proprioception improvement, joint mechanical stress reduction, change of brain activation and sensitization, attenuation of inflammation, emotion modulation and social support, are discussed.

Roles and mechanism of microRNAs in the regulation of skeletal muscle insulin resistance / 生理学报

Insulin resistance is a common pathophysiological mechanism of obesity and type 2 diabetes mellitus. Skeletal muscle is one of the major target organs of insulin-mediated glucose uptake, metabolism and utilization, and it is the earliest and most important site of insulin resistance. Studies have shown that the impairments of glucose uptake, insulin signaling pathway and mitochondrial biosynthesis are closely related to skeletal muscle insulin resistance. When insulin resistance develops in skeletal muscle, multiple microRNAs (miRNAs) are up-regulated (miR-106b, miR-23a, miR-761, miR-135a, Let-7 and miR-29a) or down-regulated (miR-133a, miR-149 and miR-1). They participate in the regulation of skeletal muscle glucose uptake, insulin signaling pathway and mitochondrial biogenesis, and thus play important roles in the occurrence and development of skeletal muscle insulin resistance. Therefore, these miRNAs may serve as potential targets for the treatment of skeletal muscle insulin resistance or diabetes.

Signaling pathways controlling skeletal muscle mass / 生理学报

The skeletal muscle mass accounts for more than 40% of the body weight of healthy adults. The skeletal muscle not only plays an important role in physical activities but also affects the function of other organs as a secretory organ secreting multiple muscle factors. Therefore, it is important to maintain the normal quantity and function of skeletal muscle. Skeletal muscle mass is the basis of skeletal muscle function and is often affected by many factors such as exercise and disease. Resistance exercise training induces increased protein synthesis in skeletal muscle cells, while limb disuse, chronic obstructive pulmonary disease, heart failure, chronic kidney disease, cachexia, Duchenne muscular dystrophy and many other pathological conditions lead to decreased protein synthesis or enhanced protein degradation of skeletal muscle cells. The process of skeletal muscle hypertrophy involves changes in multiple signaling pathways, such as IGF-1/PI3K/Akt, myostatin and G protein. On the other hand, activations of the ubiquitin-proteasome system, IGF-1/Akt/FoxO, autophagy-lysosomal pathway, NF-κB, and the glucocorticoid-mediated signaling pathways play important roles in regulating muscle atrophy. These signaling pathways regulate skeletal muscle mass and are modulated by some different conditions. This review briefly summarizes the signaling pathways of skeletal muscle mass control.

Advance in Basic Researches about Enriched Environment for Neuropathic Pain (review) / 中国康复理论与实践

Neuropathic pain is a common health problem in clinic. The enriched environment can increase the threshold of pain in models of neuropathic pain, which may associate with the alleviation of inflammation and excitability of nerves.

Mechanism of the occurrence of sarcopenia in the elderly / 生理学报

The decline in skeletal muscle mass and function with age is referred as sarcopenia. It is characterized by the muscle fiber's quality, strength, muscle endurance and metabolic ability decreasing as well as the fat and connective tissue growing. Previous studies have shown that sarcopenia in itself features decreased number and cross-sectional area of muscle fibers and the net degradation of protein, which results from the joint effects of multiple factors such as the exacerbation of inflammation, oxidative stress injury, mitochondrial dysfunction, abnormal autophagy and dysregulation of muscle quality regulatory factors. In this review, we systematically displayed the molecular mechanism of sarcopenia, which will be helpful to deepen our understanding of sarcopenia and provide potential targets for the prevention and treatment of sarcopenia.

Macrophages depletion impairs skeletal muscle regeneration by regulating inflammation and oxidative stress levels / 生理学报

The objective of this study was to explore the roles of macrophages in the regeneration of injured skeletal muscle and the mechanisms involved. Mice were randomly divided into the following groups: muscle contusion (S), muscle contusion control (S), macrophages depleted (T) and macrophages depleted control (T) groups. Muscle contusion model was created by high-energy blunt injury. Macrophages depletion model was constructed by injection of clodronate-liposomes. Their gastrocnemius muscles were harvested at the time points of 1, 3, 7 and 14 d post-injury. The changes in skeletal muscle morphology were assessed by hematoxylin-eosin (HE) staining and Masson's trichrome staining. The mRNA and protein levels of inflammatory cytokines, chemokines and oxidative stress factors were analyzed by real-time polymerase chain reaction (RCR) and Western blotting, respectively. HE staining results showed that a small amount of regenerating myofibers were observed in the S group (14 d post-injury), whereas a large number of regenerating muscle fibers were observed in the T group. Quantitative analyses showed that the sizes of regenerating myofibers were significantly smaller in the T group as compared with the S group at 14 d post-injury (P < 0.05). At the same time, Masson staining results showed that macrophage depletion significantly increased the area of fibrosis as compared with the S group at 14 d post-injury (P < 0.01). The expression levels of inflammatory cytokines, chemokines, and oxidative stress factors were increased significantly after muscle injury. Moreover, macrophage depletion increased the expressions of inflammatory cytokines, chemokines and oxidative stress factors as compared with the S group during the later stage of injury (7-14 d post-injury). These results suggest that macrophages depletion can aggravate fibrosis and impair muscle regeneration, and inflammatory cytokines, chemokines and oxidative stress factors may be involved in this process.

Fat deposition in skeletal muscle and its regulation / 生理学报

Under normal condition, there are a few lipid droplets in skeletal muscle. But in skeletal muscle acute injury, muscular dystrophy, muscle atrophy, obesity, diabetes and other pathological conditions, the fat deposition in skeletal muscle increases, which implicate that the fat deposition may play an important role in the pathogenesis of these diseases. However, the mechanisms of development and regulation of fat deposition in skeletal muscle are not clear. Clarifying the key signaling pathways and regulatory factors that affect fat deposition in skeletal muscle, and exploring new ways to improve the fat deposition in skeletal muscle will not only help to deepen our understanding of the pathogenesis of these diseases, but also provide new ideas for the treatment of these diseases. This paper reviews the research progresses and main mechanisms of fat deposition in skeletal muscle.

Research on the mechanism and regulation of overtraining-related the function of neutrophils by the inhibitor of NADPH oxidase and glutamine supplementation / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the method and mechanism for exercise-related immunosuppression via the inhibitor of NADPH oxidase diphenyleneiodonium(DPI) and glutamine supplementation and on the function of neutrophils after overtraining.</p><p><b>METHODS</b>Fifty male Wistar rats were randomly divided into five groups: a negative control group (C), an overtraining group (E), an overtraining + DPI intervention group (D), an overtraining+ glutamine supplementation group(G) and combined glutamine + DPI intervention group(DG). After 36 - 40 h from the last training, eight rats were randomly selected from each group, and blood was sampled from the orbital vein. ELISAs were used to measure serum cytokine levels and lipid peroxidation in blood plasma. Flow cytometry was used to measure neutrophil respiratory burst and phagocytosis. The activity of NADPH oxidase was assessed by chemiluminescence and the gene expression of gp91(phox) and p47(phox) of the NADPH-oxidase subunit was checked by Western blot.</p><p><b>RESULTS</b>Compared with group C, the plasma concentrations of NO increased in group G, and the NO, cytokine-induced neutrophil chemoattractant (CINC) concentrations in group DG increased significantly. The respiratory burst and phagocytosis function of neutrophils were decreased in group E, but in group DG were increased when compared with those of group E. After overtraining the expression of gp91(phox) and p47(phox) was up regulated in group E. There were no significant changes in other groups except group DG, in which the expression of gp91(phox) was down regulated. Compared with group E, the expression of gp91(phox) and p47(phox) was up regulated in group D, group G and group DG.</p><p><b>CONCLUSION</b>The activation of NADPH oxidase is responsible for the production of superoxide anions, which may be related to the decrease in neutrophil function after over training and is the mechanism of exercise-related immunosuppression. The DPI treatment combined glutamine supplementation can reverse the decrease neutrophils function after overtraining in vitro.</p>

Dietary supplement with a combination of Rhodiola crenulata and Ginkgo biloba enhances the endurance performance in healthy volunteers / 中国结合医学杂志

<p><b>OBJECTIVE</b>To determine whether the ingestion of a herbal supplement called Rhodiola-Gingko Capsule (RGC) would enhance the endurance performance of healthy volunteers and change relevant hormones in a favorable manner.</p><p><b>METHODS</b>Seventy healthy male volunteers (age ranges from 18 to 22 years old) were randomly assigned to RGC group (35 cases, each capsule containing 270 mg herbal extracts, 4 capsules per day) or placebo group (35 cases, equivalent placebo preparation) for 7 weeks using computer produced digital random method. The endurance performance, serum testosterone and cortisol levels were measured at the baseline and the endpoint.</p><p><b>RESULTS</b>Sixty-seven subjects (34 in the RGC group and 33 in the placebo group) completed a 7-week treatment. The RGC group displayed a significantly greater baseline-to endpoint increase in maximal oxygen uptake (VO(2max)) than placebo group in both absolute (P=0.020) and relative values (P=0.023). At the endpoint, the serum cortisol level was unchanged in the RGC group compared with the baseline, but it was significantly elevated in the placebo group (P<0.05). The endpoint ratio of testosterone to cortisol, a surrogate for overtraining and fatigue in endurance exercises, was also indifferent compared with the baseline in the RGC group, but significantly decreased in the placebo group (P<0.05).</p><p><b>CONCLUSION</b>The combined herbal supplement of Rhodiola and Gingko could improve the endurance performance by increasing oxygen consumption and protecting against fatigue.</p>

Treadmill running enhances the ability of learning in young rats / 生理学报

To investigate the effect of treadmill running on the ability of learning in young rats, male Sprague-Dawley rats (5 weeks of age) were used for the experiment. Animals were randomly divided into the control and running groups (n=15 in each group). The rats in running group were made run on a motor-driven treadmill for 1 week at a speed of 2 m/min for the first 5 min, at a speed of 5 m/min for the next 5 min, then at a speed of 8 m/min for the last 20 min. Then the Morris water maze was used to observe learning and memory ability of rats in both groups. The tests consisted of place navigation and spatial probe test. We found that, in place navigation training, the latency of rats in running group was less than that in control group (P<0.05); and from the third training session on, there was significant difference between the rats in control and running groups in swimming velocity (P<0.01); furthermore, it was observed that the rats in running group had stronger motivation and more exact orientation in searching for platform, which could be indicated by the index of turn angle and angular velocity. In spatial probe test, there was no significant difference between the two groups in swimming velocity, percentage of swimming distance and frequency of crossing platform in D quadrant, where the platform situated (P>0.05). These findings suggest that low speed treadmill running can enhance the ability of learning in young rats.