ABSTRACT
@# Irrespective of physiological or pathological skeletal muscle atrophy, the endocrine and motor functions of skeletal muscle are impaired. The mechanism of acupuncture to prevent and treat skeletal muscle atrophy is not only related to classical protein synthesis and decomposition, but also involves apoptosis, autophagy, muscle satellite cell proliferation and differentiation, muscle fiber type conversion, neuromuscular junction conduction, and cell energy metabolism conversion.
ABSTRACT
@#Objective To explore the effects and mechanism of electroacupuncture (EA) on denervation-induced atrophy in rats. Methods A total of 18 male Sprague-Dawley rats were divided into sham group (n=6), model group (n=6) and EA group (n=6). The latter two groups were clamped right sciatic nerve to establish atrophy model of skeletal muscle. On the second day after modeling, EA group accepted electroacupuncture on right Zusanli (ST36) and Huantiao (GB30) for two weeks. Their gastrocnemius muscles were obtained after intervention, and the wet weight ratio of the gastrocnemius muscles was calculated. The cross-sectional area (CSA) and diameter of muscle fibers were measured after HE staining. The protein expression of mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR), 70-KD ribosomal protein S6 kinase (p70S6K) and phosphorylated p70S6k (p-p70S6k) was tested with Western blotting. The gene expression of mTOR and p70S6K was detected with real-time quantitative polymerase chain reaction. Results Compared with the sham group, the wet weight ratio of the gastrocnemius muscle, CSA and diameter of the muscle fibers decreased in the model group and EA group (P<0.001), which were more in EA group than in the model group (P<0.01); the protein expression of mTOR, p-mTOR, p70S6K and p-p70S6K increased in the model group (P<0.01), and increased more in EA group (P<0.05); the gene expression of mTOR and p70S6K increased in the model group (P<0.05) , and increased more in EA group (P<0.05).Conclusion Electroacupuncture delays the atrophy of denervated skeletal muscles, which may relate to activation of mTOR/p70S6K signal pathway to impact synthesis of skeletal muscle proteins.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the effects of acupuncture at opposite acupoints on expression of hepatocyte growth factor (HGF) in rats with skeletal muscle contusion, and to explore the mechanism of acupuncture at opposite acupoints on skeletal muscle contusion.</p><p><b>METHODS</b>Fifty-four Sprague Dawley (SD) rats were randomly divided into a blank group (6 rats), a model group (24 rats) and an opposing needling group (24 rats). The model group and opposing needling group were further divided into 1-day subgroup, 3-day subgroup, 5-day subgroup and 7-day subgroup, 6 rats in each one. No intervention was given in the blank group, while the model of skeletal muscle contusion was established in the model group and opposing needling group by self-made contusion device. 24 hours after contusion, electroacupuncture (EA) was applied at "Zusanli" (ST 36) and the corresponding points ofpoints at health side for 15 min, once a day. The subgroups of opposing needling group were treated for 1 day, 3 days, 5 days and 7 days, respectively. No treatment was given in the model group. Samples were collected in the subgroups 1 day, 3 days, 5 days and 7 days after treatment. The morphological change of injured gastrocnemius muscle was observed by using microscope after HE staining. The positive cell rate of proliferating cell nuclear antigen (PCNA) was detected by immunohistochemistry. The expression levels of HGF protein and PCNA protein were observed by Western blot.</p><p><b>RESULTS</b>① The results of HE staining showed that, 1 day after contusion, the inflammatory cells of gastrocnemius muscle in the opposing needling group were less than those in the model group; 3 days and 5 days after contusion, myoblasts and myotubes in the opposing needling group were more than those in the model group; 7 days after contusion, the neonatal muscle cells in the opposing needling group were more than those in the model group. ② The results of immunohistochemistry showed that, 1 day, 3 days and 5 days after contusion, the positive cell rate of PCNA in the opposing needling group was significantly higher than that in the model group (all<0.001); 7 days after contusion, the positive cell rate of PCNA in the opposing needling group was significantly less than that in the model group (<0.001). ③ The results of Western blot showed that, 1 day, 3 days and 5 days after contusion, the expression of HGF protein and PCNA protein in the opposing needling group was significantly higher than that in the model group (all<0.05); 7 days after contusion, the expression of HGF protein and PCNA protein in the opposing needling group was significantly lower than that in the model group (all<0.05).</p><p><b>CONCLUSION</b>Acupuncture at opposite acupoints could regulate the expression of HGF and promote the activation, proliferation, migration and differentiation of muscle satellite cells in rats with skeletal muscle contusion, which could speed up the process of skeletal muscle injury repair.</p>