OBJECTIVE: To investigate the biological characteristics of human muscle satellite cell cultured in vitro. METHODS: Human muscle satellite cells were obtained from skeletal muscle biopsies of six patients during corrective orthopedic surgery, cultivated in growth medium for ten days, then in differentiation medium for additional five days. Human satellite cells were identified with monoclonal antibody against desmin. Cells were observed under phase contrast microscopy. RESULTS: Human muscle satellite cells proliferated in growth medium, and fused to form myotubes in differentiation medium. After 24 hours in differentiation medium, the confluent satellite cells began to fuse actively and achieved the top level at 72 hours. CONCLUSION: Human muscle satellite cell can proliferate and differentiate in appropriate culture condition. Immunocytochemical detection of desmin is the effective early method to determine satellite cell.
OBJECTIVE: To observe the changes of heme oxygenase-1 (HO-1) expression in the skeletal muscle after ischemia-reperfusion of hind limb in rats. METHODS: A model of hind limb ischemia was made by clamping femoral artery with a microvascular clip. Soleus muscle was obtained from the animals received sham operation, 4 h ischemia without reperfusion and 2 h, 4 h, 8 h, 16 h, 24 h reperfusion after 4 h ischemia. Soleus histology and malondialdehyde (MDA) content were measured. The levels of HO-1 mRNA and protein were measured in different time by Northern blotting, Western blotting and immunohistochemistry technique. RESULTS: After ischemia-reperfusion of limb, HO-1 mRNA increased at the 2nd hour, reached a peak at the 8th hour, and returned toward baseline at the 24th hour. The change of protein level was essentially in agreement with that of mRNA. Immunohistochemical results showed that HO-1 expressed primarily in skeletal muscle cytoplasma. There were no positive signals of mRNA and protein in sham group and in ischemia group. After limb reperfusion, MDA contents in the soleus muscle increased significantly when compared with that in the sham group (P lt; 0.05). MDA content of the 8th after reperfusion decreased significantly when compared with that of the 4 h after reperfusion (P lt; 0.05). CONCLUSION: Ischemia-reperfusion can induce HO-1 expression in skeletal muscle in rats, which may provide protection for injured tissue.
Objective To investigate the pathological changes in the neuromuscular junction during ischemiareperfusion(IR) in the skeletal muscle. Methods Forty-eight healthy adult Wistar rats (24 male, 24 female) were equally randomised into the following 6 groups: Group A (control group): no ischemiareperfusion; Group B: ischemia by clamping the blood vessels of the right hindlimb for 3 hours; Group C: ischemia by clamping for 4.5 hours;Group D: ischemia by the clamping for 4.5 hours followed by reperfusion for 1.5hours; Group E: ischemia for 4.5 hours followed by reperfusion for 24 hours; and Group F: ischemia for 4.5 hours followed by reperfusion for 2 weeks. Then, the medial head of the gastrocnemius muscle flap model was applied to the right hindlimb of each rat. The medial head of the gastrocnemius muscle was isolated completely,leaving only the major vascular pedicle, nerve and tendons intact.The proximal and distal ends (tendons) were ligated while the vessel pedicle was clamped. And then, Parameters of the muscle (performance,contraction index,colour,edema,bleeding) were observed. The muscle harvested was stained with gold chloride(AuCl3) and the enzymhistochemistry assay (succinate dehydrogenase combined with acetylcholine esterase) was performed. Morphology and configuration of the neuromuscular junction were observed during the ischemiareperfusion injury by means of the AuCl-3 staining. The result of the enzymhistochemical reactions was quantitatively analyzed with the computer imageanalysis system. And then, additional 5 rats were prepared for 3 different models identical with those in Groups A, C and E separately. The specimens were harvested from each rat and were stained with HE and AuCl-3, and they were examined under the light microscope. Results During the period of ischemia, the skeletal muscle of Group B showed the colour of purple and edema.The colour and edema became worse in Group ,while dysfunction of elasticity and contraction appeared obviously with plenty of dark red hemorrhagic effusion at the same time.After reperfusion,the color and edema of muscle in Group D became improved while the elasticity and function of contraction was not improved. Hemorrhagic effusion of Group D turned clearer and less than Group C.Group E was similar to Group D in these aspects of muscle except for much less hemorrhagic effusion. Skeletal muscle in Group F showed colour of red alternating with white, adhesion,contracture of muscle, exposure of necrotic yellow tissue and almost lost all its functions. The AuCl3 staining showed that during IR, necrosis of the myocytes was followed by degeneration of their neuromuscular junctions, and finally the nerve fibers attached to these neuromuscular junctions were disrupted like the withering of leaves. The enzymhistochemistry assay showed thatthere was no significant difference in the level of acetylcholine esterase between the ischemic group (Groups B and C) and the control group (Group A) (Pgt;0.05). However, the level of acetylcholine esterase in all the reperfused groups (Groups D, E and F) decreased significantly when compared with the control group（Group A）and the ischemic groups (Groups B and C) (Plt;0.01). Conclusion The distribution of the nerve fibers and the neuromuscular junctions in the mass of the muscles is almost like the shape of a tree. The neuromuscular junction seems to be more tolerant for ischemia than the myocyte. Survival ofthe neuromuscular junction depends on its myocytes alive. Therefore, an ischemiareperfusion injury will not be controlled unless an extensive debridement of the necrotic muscle is performed.
Objective To investigate the influence of clenbuterol on the expression of nerve growth factor (NGF) in denervated red and white muscles and the neurotrophism of the denervated muscles.Methods Sixty-four Wister rats, weighed 200-250 g, were divided into 8 groups(8 rats per group), including 4 experimental groups and 4 control groups. The denervated model was made in rats by dissection of sciatic nerves. Clenbuterol was given at a dose of 200 μg/kg per day in the experimental group, saline in the control group. The expression of NGF was measured with immunohistochemistry after 1, 3, 7 and 14 days of injury. The culture methods of dorsal root ganglions of the chick embryos were used to measure the neurotrophism of extracts of the muscles. Results Compared with the control groups, the NGF content of gastrocnemious(GAS) increased on the 1st day (Plt;0.05) and the NGF content of soleus(SOL) increased greatly on the 1st, 3rd and 7th dayafter injury in the experimental groups (Plt;0.01). In the experimental groups, the NGF amount of GAS reached the highest value on the 1st day after injury(Plt;0.01) and then decreased gradually. And the NGF amount of SOL had slight difference between different time. The NGF content of the SOL was higher than that of GASon the 7th day (Plt;0.05). The sensory neurotrophism of the extracts was similar between SOL and GAS.Conclusion Clenbuterol can change the expression of NGF in denervated muscles, but the change was different in SOL and GAS. The sensory neurotrophism of the denervated muscles were determined by all of the neurotrophic factors in them.
OBJECTIVE: To study the influence of the electric stimulation of denervated muscle atrophy. METHODS: Sixteen SD rats were made the model of denervated skeletal muscle in two lower limbs by cutting off the sciatic nerve and femoral nerve. The right gastrocnemius muscle was stimulated with JNR-II nerve amp; muscle recovery instrument by skin as the experimental side and the left was not treated as the control side. The muscle histology, ultrastructure, fibrillation potential amplitude, Na(+)-K(+)-ATPase and Ca(2+)-ATPase activities were observed 2 weeks and 4 weeks after operation. RESULTS: Electric stimulation could protect mitochondria and sarcoplasmic reticulum from the degeneration. The reduction rates of muscle cell diameter and cross section in the experimental side were slower significantly than those in control side. There was no influence on fibrillation potential amplitude in the both sides after electric stimulation. The reduction rates of Na(+)-K(+)-ATPase activity in the experimental side were slower 15.59% and 27.38% respectively than those in the control side. The reduction rates of Ca(2+)-ATPase activity in the experimental side were slower 4.83% and 21.64% respectively than those in the control side. CONCLUSION: The electric stimulation can protect muscle histology, electrophysiology and enzymic histochemistry of denervated skeletal muscle from the degeneration. The electric stimulation is an effective method to prevent and treat muscle atrophy.
OBJECTIVE: To investigate the effects of bone morphogenetic protein (BMP) on the proliferation and collagen synthesis of skeletal muscle satellite cells. METHODS: Skeletal muscle satellite cells were harvested and cultured in vitro. The 0 ng/ml, 50 ng/ml, 100 ng/ml, 500 ng/ml, and 1000 ng/ml BMP were used to induce skeletal muscle satellite cells for 48 hours. Cell proliferation, rate of myotube formation and collagen-1 synthesis were measured. RESULTS: BMP promoted cell proliferation and reduced the rate of myotube formation. Collagen synthesis increased when skeletal muscle satellite cells were induced with more than 500 ng/ml BMP. And the higher the concentration of BMP was, the ber this effect became. CONCLUSION: BMP can enhance the proliferation of skeletal muscle satellite cells and change their differentiation from myoblasts to osteoblasts.
Objective To study the protective effects of ischemic preconditioning(IP) duration against ischemic reperfusion injury of skeletal muscle. Methods Thirty-six Wister rats were made amputation-like models, which underwent temporary amputation at the level of the femur, excluding the femoral vessels. They were divided into 6 groups(n=6) according to different treatments before ischemiareperfusion: group A(4 hours of ischemiareperfusion); groups B, C, D, E(5, 10,15, 20 minutes of ischemia and 5, 10, 15, 20 minutes of reperfusion respectively, for 3 cycles, 4 hours ischemiareperfusion ); group F (no ischemia-reperfusion). The malondialdehyde(MDA), the extent of edema and necrosis of skeletal muscle were measured to observe protective effects of different ischemic preconditioning duration. Results Five minutes of ischemic preconditioning（IP5）could protect skeletal muscle of ischaemia against necrosis and the survival area of the muscle was 82.47%.The effects of IP10 and IP 15 were significantly superior to that of IP5 and the survival areas of the muscle were 89.03% and 89.49%. The effect of IP20(78.27%) was significantly inferior to that IP5. IP5 could reduce edema of skeletal muscle, the effect of IP10 was significantly superior to that of IP5. IP5, IP 10,and IP 15 could decrease the level of MDA, but IP20 did not decrease it. Conclusion The trend of protective effect of IP on ischemia-reperfusion injury of themuscle in rats first rise to the peak and then go down,10minutes ofIPis optimal.
OBJECTIVE: To define how to preserve the severed limbs to prolong the period of replantation. METHODS: The original articles about preservation of severed limbs in recent years were reviewed, it was suggested that the period of replantation was determined by the injury of skeletal muscle. RESULTS: When the environment of severed limbs was changed, the injures of skeletal muscle could be decreased. CONCLUSION: After the severed limbs are reasonably preserved, the period of replantation may be prolonged.
【Abstract】 Objective To investigate the effect of massage on quadriceps femoris repair and the expressions of Desmin and α-Actin in rabbits so as to explore the possible molecular mechanisms of massage in repair of muscle injury. Methods Twenty-seven New Zealand white rabbits, weighing (2.0 ± 0.5) kg, were randomly divided into 3 groups: groups A (n=3), B (n=12), and C (n=12). In group A, the rabbits were not treated as controls; in groups B and C, the rabbit models of quadriceps femoris injury were prepared by self-made beater. In group B, no massage therapy was given as nature recovery controls; in group C, RT-N2 intelligent massage device was used for massage therapy at 8 days after injury, at 3 000-3 100 r/min for 15 minutes, every day for 7 days or for 14 days. The quadriceps femoris specimens were taken from 6 rabbits of groups B and C at 14 days and 21 days, respectively. HE staining was employed to detect the histomorphological change. Immunohistochemistry staining and Western blot were used to detect Desmin and α-Actin expressions. The massage therapy effect was evaluated by the histomorphological change and Desmin and α-Actin expressions. Results All rabbits survived to the end of experiment in groups B and C. No histological change was found with regular order of muscle fibers and no connective tissue in group A; obvious tissue necrosis was seen with broken muscular fibers, muscle atrophy, and irregular order in group B; and in group C, the skeletal muscle morphology and muscle atrophy were obviously improved with regenerated muscle fibers when compared with group B. Immunohistochemistry staining showed that the Desmin and α-Actin expressions obviously reduced in groups B and C, which were significantly weaker than that in group A (P lt; 0.05); the Desmin and α-Actin expressions were significantly ber in group C than in group B (P lt; 0.05), and at 21 days than at 14 days in group C (P lt; 0.05). Western blot results showed that the Desmin and α-Actin expressions were significantly higher in group A than in groups B and C (P lt; 0.05), and the expressions were lowest at 14 days in group B. Conclusion The histomorphology and cytoskeletal structure can be significantly improved after massage, which may help to repair muscle injury by up-regulation of Desmin and α-Actin expressions.
Objective To explore the rule of changes in the myoblast stem cells (satellite cells) in the denervated and innervated muscles and to find out thecellular mechanism of the changes in the muscle morphology and function. Methods The denervated muscleatrophy models were established from 27 Wistar rats aged 1 month. One to six months after operation, examinations of the histology, histochemistry, and morphology were performed on the specimens from the bilateral triceps muscle of the calves of 3 rats in each month. Meanwhile, examination of the cell biology was performed on the specimens from the bilateral triceps muscleof the calves of 1 rat 1, 2 and 3 weeks after operation, and monthly for 1-6 months after operation. The innervation models were established from 35 Wistar rats aged 1 month. Immediately after the denervation, and monthly for 1-6 months after operation, 5 denervated rats underwent the nerve implantation. The changes in the electrophysiological index were observed dynamically until 8 weeks after the nerve implantation.Results After the denervation, the muscle wet weight and the muscle cell area decreased rapidly, but the content of the collagen fibers increased gradually. The number of the nucleus in the period of proliferationwas the greatest 3-4 months after the denervation, and then decreased rapidly.The muscle satellite cells began to increase obviously 3 weeks after the denervation, but 2 months later they decreased rapidly and 4 months later the number of the cells was the smallest. Four to five weeks after innervation, the muscle action potential could be induced, and the best innervation effect could be achieved in the implanted nerve after the 2-3 months on denervation, and at this time the differentiation ability of the satellite cells was the best. Conclusion Four months after the denervation of the skeletal muscle, an extremely small number of the satellite cells can make the muscle enter the irreversible atrophy. However, when the innervation is performed 2-3 months after the denervation, the actively-growing satellite cells can promote a better functional recovery ofthe atrophic muscle.