OBJECTIVE Because of its special biological characteristics, myoblast might play a role in gene delivery and cell-to-biomaterial interactions. In this paper, the biological features of myoblast and its application on gene therapy and tissue engineering was discussed. METHODS Documents about proliferation and differentiation of myoblast were reviewed in details. The prospects of its application on gene therapy and tissue engineering were also presented. RESULTS Myoblast was important in muscle regeneration. The activation of myoblast to proliferate and differentiate was the very beginning of regeneration after injury. The cultured myoblast had high potential to proliferate, it was ready to fuse with each other and to form myotube (the special behavior of myoblast differentiation). Myoblast transplantation had been studied as a possible treatment for inherited myopathies, such as Duchenne muscular dystrophy. The transplanted myoblast could fuse with host myofibers, so the delivered target gene integrated into host. Several myoblast-mediated gene delivery system had been established, including the gene delivery of human factor IX (hFIX), erythropoietin (EPO) and clony stimulating factor-1 (CSF-1). Results from animal experiments demonstrated that myoblast-mediated gene delivery could be used as gene therapy for some inherited diseases. And recently, some authors have shown great interest in the interaction between myoblast and type I collagen gels. It was found that myoblast could keep on proliferating and differentiating in collagen gels and could form discoid, tubular materials. CONCLUSION Myoblast has great importance in gene therapy and tissue engineering. It is suggested that more efforts should be made in this field.
Objective To explore the possibilityof constructing tissue engineering muscles by combining allogeneic myoblasts with small instestinal submucosa(SIS) in rabbits.Methods A large number of purified myoblasts were obtained with multiprocedure digestion and repeated attachment method from skeletal muscles taken from extremities of immature rabbits which were born 7 days ago. The myoblasts were labeled with BrdU, and then combined with SIS to construct tissue engineering muscles. This kind of tissue engineering muscles were grafted into the gastrocnemius muscle defect (1.5 cm in length, 1.0 cmin width) of fifteen rabbits as the experimental group. The SIS was grafted into the same position in the control group. The rabbits were sacrificed 4, 6, 8 weeks after operation. The tissue engineering muscles were evaluated by macroscopic、histological and immunohistochemical observations, and by quantitative analysis of local immunocyte in the grafting site. Results Allogeneic myoblasts with SIS were combined perfectly in vitro. The SIS was connected tightly to surrounding skeletal muscles and inflammation response was obvious 4 weeks after grafting.The SIS began to break down and inflammation response became slight 6 and 8 weeks after operation. Compared with that of 8th week, the quantitative analysis oflocal immunocyte in 4th and 6th week in both experimental and control group hassignificance(Plt;0.05). Newly formed muscle tissues were found around SIS in the experimental group in 4th, 6th, and 8th week. Expression of BrdU and myosin immunohistochemical staining were positive in the experimental group and negative inthe control group.Conclusion Tissue engineering muscles of rabbits which are constructed by combining allogeneic myoblasts with SIS can survive and proliferate.
Objective To study the construction feasibility of a biodegradable artificial esophagus by the squamous epithelial cells and the myoblast cells seeded on the small intestinal submucosa(SIS) and to investigate the growth patternand angiogenesis of the co-cultured human embryonic squamous epithelial cells and the skeletal myoblasts in vivo. Methods The squamous epithelial cells and the myoblast cells were obtained from the 20-week aborted fetus. Both of their cellswere marked by 5-BrdU in vitro.The isolated cells were then seeded on the SIS and co-cultured in vitro for 24 hours, and then the compound of the cells and the SIS was transplanted into the subcutaneous tissue of the athymismus mice. The observation on the morphology and the cytokeratin AE3 and α-actin specified immunohistochemistry of the squamous epithelial cells and the myoblastcells was performed at each of the following time points: 3 days, 1 week, 2 weeks, and 3 weeks after transplantation. Results The morphological observation indicated that the cultured cells could penetrate into the small intestinal submucosa and form several-layered cell structures, and that the compound of the cells and the SIS could have angiogenesis within 2-3 weeks. The 5-BrdU specified immunohistochemical observation suggested that the cells growing in the small intestinal submucosa scaffold might be the cells transplanted.The cytokeratin AE3 specified and α-actin specified immunohistochemical studies demonstrated that the transplanted cells could differentiate in vivo. Conclusion It is possible to fabricate the framework of a biodegradable artificial esophagus with the epithelial cells and the myoblast cells seeded on the small intestinal submucosa.
ObjectiveTo research the effect of chondroitin sulfate (CS) on the proliferation of myoblasts and the formation of myotube. MethodsThe myoblasts at passage 5 were used to prepare the cells suspension (1×108 cells/mL), and the experiment was divided into 4 groups based on CS concentration in the medium:group A (0 μg/mL), group B (50 μg/mL), group C (100 μg/mL), and group D (200 μg/mL). The cell morphology and myotube formation were observed by inverted microscope at 4, 5, and 8 days after treatment; MTT was used to detect the cell proliferation at 6 days, and the number of myotube was calculated by HE staining at 8 days. ResultsCells showed spindle shape after adherent, with ovoid nuclei and dense cytoplasm under inverted microscope. When the cell adherent rate was 90%, cells arranged in whorls swirled and showed long fusiform adherent growth; and then nuclei fusion resulted in formation of multincleated myotubes. At 8 days, most myoblasts fused to form myotube in group A, but less myotube was observed in groups B and C, and the least myotube in group D. The absorbance (A) values of groups A, B, C, and D were 0.045 2±0.004 4, 0.540 4±0.096 7, 0.660 9±0.143 4, and 1.069 0±0.039 0 respectively, showing significant difference between other groups (P<0.05) except between groups B and C P>0.05). HE staining observation showed that most myoblasts fused to form myotube in group A, but less myotube in groups B and C, and the least myotube in group D. The number of myotube of groups A, B, C, and D were 222.01±30.02, 193.13±42.46, 170.26±11.96, and 136.88±16.78 respectively, showing no significant difference among groups (F=1.658, P=0.252). ConclusionCS can significantly promote the proliferation of myoblast, the promotion is the biggest when CS concentration is 200 μg/mL.
OBJECTIVE: To investigate the biological characteristics of continuously subcultured human embryonic skeletal myoblasts, and choose the optimal seeding cells for muscle tissue engineering. METHODS: Human embryonic skeletal myoblasts were subcultured in vitro. The growth curve, rate of myotube formation(RMF) were used to evaluate the proliferative and differentiation ability of myoblasts, and to investigate the influence of fibroblasts contamination on myoblasts. RESULTS: The beginning 6 passages of myoblasts showed b proliferative and differentiation ability. From the 8th to 20th passage, the rate of fibroblasts contamination was increased, it mainly showed the growth characteristics of fibroblasts with increased proliferation and low differentiation. After subcultured to the 20th passage, the degeneration of myoblasts was obvious. CONCLUSION: The myoblasts within 6 passages should be used as the seeding cells of muscle tissue engineering because of b proliferative ability and high rate of myotube formation.
Objective To study the effect of allogenic different cells injected into denervated muscles on nerve regeneration. Methods Thirty-six adult female SD rats, weighed 120-150 g, were divided into four groups randomly (n=9, each group). Left sciatic nerves were cut down on germfree conditions and given primary suture of epineurium. Different cells were injected into the muscles of calf at once after operation every seven days and in all four times (group A: 1 ml Schwann cells at concentration of 1×106/ml; group B: 1 ml mixed cells of Schwann cells and myoblast cells at concentration of 1×106/ml; group C: 1 ml extract from the culture medium of kidney endothelial cells; and group D: 1 ml culture medium without FCS as control ). After 3 months, the specimen was observed on macrobody and histology, and the densities of neurilemma cell and myoceptor were counted. Results The means of proximate neurilemma cells were 0.187 7±0.054 2 in group A, 0.155 1±0.032 1 in group B, 0.072 4±0.023 7 in group C, and 0.187 7±0.054 2 in group D. The densities of myoceptor were 6.000±0.866 in group A，9.000±2.291 in group B,12.780±1.394 in group C, 3.110±0.782 in group D. Conclusion Schwann cells, mixed cells of Schwann cells with myoblast cells, and the extract from kidney endothelial cells canall accelerate the nerve regeneration. And the effect of extract from the kidney endothelial cell is superior to that of Schwann cell and mixed cell.
Objective To research the protective effects of different allogeneic cells injected into denervated muscles on ventricornual motor neuron. Methods Thirty-six adult female SD rats, weighting 120-150 g, were individed into four groups randomly and each group had nine. Left ischiadic nerves of all the SD rats, which were cut down on germfree conditions,were operated by primary suture of epineurium. Different cells were injected into the triceps muscles of calf in each group after operation with once a week for 4 weeks:1 ml Schwann cells (1×106/ml) in group A, 1 ml mixed cells ofSchwann cells and myoblast cells (1∶1,1×106/ml) in group B, 1 ml extract from the mixed cells of Schwann cells, myoblast cells and endotheliocytes (1∶1∶1,1×106/ml)in group C,and 1 ml culture medium without FCS as control group(group D). The observation of enzymohistochemistry and C-Jun expression in the ventricornual motor neuron was made after three months of operation. Results After 3 months of operation, the expressions of C-Jun in groups A, B and C were superiorto that in group D; the number of neuron was more than that of group D. The expressions of C-Jun in the ventricornual motor neuron were as follows: 128.591±0.766 in group A, 116.729±0.778 in group B, 100.071±2.017 in group C and 144.648±2.083 in group D; showing statistically significant difference between groupsA, B, C and D(P＜0.01). Enzymohistochemistry showed the well outlined and wellstacked cell body of neuron in groups A, B and C, and illdefined boundary of cytoplasm and nucleus. There was statistically significant defference in enzyme activity of the ventricornual motor neuron between groups(P＜0.01). Conclusion All of the Schwann cells,mixed cells of Schwann cells with myoblast cells,and the extract from Schwann cells, myoblast cells and endotheliocytes can protect the ventricornual motor neuron. And the protectiveeffect of the extract from Schwann cells, myoblast cells and endotheliocytes is superior to that of Schwann cells and mixed cells.
【Abstract】 Objective To construct tissue engineered skeletal muscle in vivo using glial cell derived neurotrophic factor (GDNF) genetically modified myoblast (Mb) on acellular collagen sponge with hypoglossal nerve implantation, and to observe whether structural or functional connection could be established between engineered tissue and motor nerve or not. Methods Mbs were isolated from 7 male Lewis rats at age of 2 days, cultured and genetically modified by recombinant adenovirus carrying GDNF cDNA (MbGDNF). Calf skin-derived acellular collagen sponge was used as scaffold; cell adhesion was detected by scanning electron microscope after 24 hours. Hypoglossal nerve was implanted into Mb-scaffold complex (Mb group, n=27) or MbGDNF-scaffold complex (MbGDNF group, n=27) in 54 female Lewis rats at age of 8 weeks. HE staining was performed at 1, 6, and 12 weeks postoperatively, and immunohistochemistry staining and fluorescence in situ hybridization were used. Results MbGDNF could highly expressed GDNF gene. Mb and MbGDNF could adhere to the scaffold and grew well. HE staining showed tight junctions between implant and peripheral tissue with new muscle fiber and no distinguished line at 12 weeks in 2 groups. Immunohistochemistry staining showed that positive cells of myogenin and slow skeletal myosin were detected, as well as positive cells of actylcholine receptor α1 at 1, 6, and 12 weeks. The positive cells of Y chromosome decreased with time. At 1, 6, and 12 weeks, the positive neurons were 261.0 ± 6.6, 227.3 ± 8.5, and 173.3 ± 9.1, respectively in MbGDNF group, and were 234.7 ± 5.5, 196.0 ± 13.5, and 166.7 ± 11.7, respectively in Mb group; significant differences were found between 2 groups at 1 and 6 weeks (P lt; 0.05), no significant difference at 12 weeks (P gt; 0.05). Conclusion Connection can be established between engineered tissue and implanted hypoglossal nerve. Recombinant GDNF produced by MbGDNF might play a critical role in protecting central motor neurons from apoptosis by means of retrograde transportation.
【Abstract】 Objective To investigate the effect of IGF-1 on the growth of primary human embryonicmyoblasts. Methods The method of incorporation of 3H-TdR was used to evaluate the abil ity of prol iferation of myoblasts.The count per minute (CPM) values of myoblasts at different concentrations(1, 2, 4, 8, 16 and 32 ng/mL) of IGF-1 were measured,and dose-effect curves were drawn to choose the optional concentration of IGF-1 to promote the prol iferation. Then theexperimental group of myoblasts received the addition of the optional concentration of IGF-1 in the growth medium, the controlgroup just received the growth medium. The flow cytometry was used to detect the cell cycle . The method of incorporation of3H-TdR was used to measure the peak-CPM. The myotube fusion rate was measured in myoblasts with different concentrations(0, 5,10, 15, 20, 25 and 30 ng/ mL) of IGF-1 in fusion medium, the dose-effect curves were also drawn, so as to decided the optional concentrationof IGF-1 in stimulating differentiation. Fusion medium with optional concentration of IGF-1 was used in experimentalgroup, and the control group just with fusion medium. The fusion rate of myotube and the synthesis of creatine kinase(CK) weredetected in both groups. Results The optional concentration of 5 ng/mL IGF-1 was chosen for stimulating prol iferation . It was shown that the time of cell cycle of control was 96 hours, but that of the experimental group was reduced to 60 hours. The results of flow cytometry showed that the time of G1 phase, S phase and G2M phase was 70.03, 25.01 and 0.96 hoursrespectively in control group, and were 22.66, 16.47 and 20.87 hours respectively in experimental group. The time-CPM value curves showed that the peak-CPM emerged at 96 hours in control group and 48 hours in experimental group, which was in agreementwith the results of the flow cytometry. The optional concentration stimulating prol iferation was 20 ng/mL IGF-1. Compared with control, the quantity of CK was increased by 2 000 mU/mL and the fusion rate was elevated by 30% in experimental group. Conclusion The concentrations of 20 ng/mL IGF-1 can elevat obviously the fusion rate and the quantity of CK. IGF-1 can enhance the prol iferation and differentiation of myoblasts via inducing the number of myoblasts at G1 phase and increasing the number of myoblasts at S and G2M phases.
Objective To investigate the expression of micro-dystrophin gene in myoblast cultured in vitro, to explore the possibil ity of combining myoblast transplantation with gene transfer for Duchenne muscular dystrophy therapy. Methods Competent Escherichia coli JM109 was prepared, which transformed with plasmid pSL139, and positive clones were picked to cultivate. Plasmid was extracted with Alkal ine lysis method and cutted with both Pvu I and Cla I enzyme. Agarose gel electrophoresis was employed to take pictures. Ten healthy 5-7 days old male C57/BL10 mice were selected, weighing4-5 g, the primary and subcultured myoblasts were cultured with multi-step enzymatic digestion and differential adhesionmethod, and Desmin immunofluorescent method was used to identfy. The 3rd generation myoblasts that were transfected with plasmid pSL139 mediated by l iposome served as the experimental group, untransfected cells served as the control group. After 48 hours of transfection, the expressions of micro-dystrophin mRNA and protein in myoblasts were detected with RTPCR and cell immunofluorescent methods, and the transfection efficiency was caculated. Results After pSL139 plasmids being digested and for 40 minutes agarose gel of electrophoresis, 3.75 kb fragment of target gene and vector were observed. The cells were almost uniform, and triangular or diamond shape after 24-48 hours of culture; the cells turned to fusion manner and could be passaged after 4-6 days. Desmin immunofluorescent result showed that green fluorescence was seen in cytoplasm of most 2nd myoblasts, and the purity of the myoblasts was above 90%. At 48 hours after transfection of myoblasts with plasmid pSL139, RT- PCR results showed that about 300 bp fragment was seen in the experimental group and the control group, and the brightness was higher in experimental group. Immunofluorescent staining displayed that green fluorescence was seen in the cytoplasm of the myoblasts in the experimental group and no green fluorescence in the control group; the expression efficiency of positive cells for micro-dystrophin was 45%-55% in experimental group. Conclusion Micro-dystrophin gene can highly express at the levels of mRNA and protein respectively in myoblasts transfected with plasmid pSL139 mediated by l iposome.