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BACKGROUND: α-lipoic acid is named as “nature antioxidant” and “mitochondrial nutrition”. But it is unclear whether α-lipoic acid can be used to protect skeletal muscle with chronic hypoxia exposure, as wel as the relative mechanism. OBJECTIVE: To observe the effect of α-lipoic acid on the antioxidant enzymes and oxidative stress in rat skeletal muscle with chronic hypoxia exposure, and to investigate the relative signaling pathway of α-lipoic acid. METHODS: Thirty-six Sprague Dawley rats were randomly divided into three groups: normoxia control group, hypoxia control group, and hypoxia+α-lipoic acid group. Rats in the hypoxia control group were subjected to hypoxia exposure in normobaric hypoxic tent with 11.3% oxygen concentration. Rats in the hypoxia+α-lipoic acid group were induced by adding α-lipoic acid (0.25%) in the normal diet. Al the interventions were lasted for 4 weeks. RESULTS AND CONCLUSION: α-lipoic acid in hypoxia could markedly enhance the mitochondrial Sirtuin-3 expression, improve the mitochondrial adenosine triphosphate synthesis activity and membrane potential, up-regulate the mitochondrial state 3 respiratory rate, respiratory control ratio and ratio of phosphorus to oxygen, down-regulate the mitochondrial state 4 respiratory rate and promote and up-regulate the activity of mitochondrial antioxidant enzymes such as manganese superoxide dismutase, glutathione peroxidase and catalase, thus inhibiting mitochondrial H2O2 generation rate and reducing mitochondrial malondialdehyde level. The results indicated that α-lipoic acid could improve the efficiency of energy metabolism of chronic hypoxia skeletal muscle mitochondria and inhibit reactive oxygen generation, and it could inhibit the oxidative stress through improving antioxidant enzyme activity of mitochondria. The protection mechanism of α-lipoic acid on hypoxia skeletal muscle mitochondria may be related to the increasing of mitochondrial state 3 respiratory rate.
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10.3969/j.issn.2095-4344.2013.25.010
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10.3969/j.issn.2095-4344.2013.25.004
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10.3969/j.issn.2095-4344.2013.26.016
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10.3969/j.issn.2095-4344.2013.25.017
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10.3969/j.issn.2095-4344.2013.25.014
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10.3969/j.issn.2095-4344.2013.26.015
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10.3969/j.issn.2095-4344.2013.26.001
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10.3969/j.issn.2095-4344.2013.23.011
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BACKGROUND: Vascular endothelial growth factor play an important role in promoting healing of osteoporotic fractures, but whether it can affect the bone mineral density is not clear. OBJECTIVE: To observe the correlation between serum vascular endothelial growth factor, bone mineral density and the number of osteoblasts in the ovariectomized rats. METHODS: Forty female Sprague-Dawley rats were randomly divided into ovariectomized group and control group. After 3 months, the bone mineral density of the whole body, femur and lumbar spine was measured. Rat enzyme-linked immunosorbent assay kit was used to measure the level of serum vascular endothelial growth factor. Then, the rats in two groups received femoral metaphyseal fixation, decalcified, dehydrated, embeding in paraffin, slicing and hematoxylin-eosin staining. Each slice was free to take five fields of view (10×40) in order to count the osteoblasts of femur distal metaphysis under optical microscope. RESULTS AND CONCLUSION: After ovariectomized for 3 months, the rats body mass was increased significantly (P 0.05), and the difference of the osteoblast number between ovariectomized group and control group was not significant (P > 0.05). This indicated that there was no correlation between bone mineral density and the number of osteoblasts and vascular endothelial growth factor level in the ovariectomized group and the control group. These findings suggest that the bone mineral density is reduced and the body mass is increased in the ovariectomized rats, and the reduced bone mineral density of ovariectomized rats may be irrelevant with the change of serum vascular endothelial growth factor.
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BACKGROUND: During conventional treatment for bone tuberculosis, there is a low effective concentration of anti-tuberculosis drugs, and the therapeutic effect is poor. OBJECTIVE:To develop a new biomaterial as a slow-release artificial carrier that can be directly implanted into the surrounding tissue of bone tuberculosis, maintain a certain anti-tuberculosis drug concentration for a long time, thereby playing an effective therapeutic action. METHODS:Rifampicin/polylactic acid/glycolic acid microspheres and isoniazid/polylactic acid/glycolic acid microspheres were prepared using the emulsion-solvent evaporation method. Usingα-cyanoacrylate, a biological adhesive, two kinds of microspheres were processed into a long-term slow-release bicomponent drug carrier. Then, in vitro release characteristics of the dual-drug sustained-release carrier were observed. After that, the dual-drug sustained-release carrier was implanted into rabbit intertrochanteric femur bone defects for observing drug release concentrations, histocompatibility and bone defect healing at different time points after drug delivery carrier implantation. RESULTS AND CONCLUSION:For rifampicin/polylactic acid/glycolic acid microspheres, the mean particle size was (240±13)μm, and the drug loading load rate was (26±1.5)%. For isoniazid/polylactic acid/glycolic acid microspheres, the mean particle size was (250±10)μm, and drug loading rate was (28±1.8)%. The in vitro cumulative release rate could reach 80%for rifampicin and 90%for isoniazid at day 90. The in vivo released concentration of rifampicin and isoniazid within 90 days was (0.5±0.4) and (0.6±0.3)μg/g, respectively. There were a smal amount of infiltrated neutrophils between the fascia and muscle fibers after the drug delivery carrier was implanted, and the amount of neutrophils in the muscle were reduced significantly at day 59. X-ray plain film showed that bone defects decreased obviously in size. These findings indicate that this dual-drug sustained-release carrier can maintain a certain anti-tuberculosis drug concentration in the surrounding tissues of bone tuberculosis, which is expected to provide a new type of dual-drug delivery carrier in the surgical treatment of bone tuberculosis.
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BACKGROUND:Bone marrow mesenchymal stem cel transplantation is considered as a promising therapy for spinal cord injury. How to more effectively promote the survival of bone marrow mesenchymal stem cel s in the area of spinal cord injury and to accelerate the recovery of motor function after spinal cord injury is a current study focus. Previous studies have found that low-frequency electromagnetic fields can promote bone marrow mesenchymal stem cel proliferation and differentiation, but whether the low-frequency electromagnetic fields can be applied to bone marrow mesenchymal stem cel transplantation for treatment of spinal cord injury requires further studies. OBJECTIVE:To discuss the effects of low-frequency electromagnetic fields on motor function of spinal cord injury rats after transplantation of bone mesenchymal stem cel s. METHODS:Sixty-four rat models of incomplete spinal cord injury at T 10 were established by compression method and then randomized into control group, transplantation group (bone mesenchymal stem cel transplantation), electromagnetic field group and combination group (electromagnetic field+bone mesenchymal stem cel transplantation). After successful modeling, bone mesenchymal stem cel s labeled with 5-bromo-2'-deoxyuridine were injected into the original injured site in the transplantation group and combination group, which were isolated and purified with the fast adherence method;while alpha-minimum essential medium was injected into the electromagnetic field group and control group for instead. At 24 hours post-operation, the electromagnetic field group and combination group were explored to low-frequency electromagnetic fields (frequency 50 Hz, magnetic indaction intensity 5 mT) for 60 minutes per day. RESULTS AND CONCLUSION:After cel transplantation for 21 days, the Basso, Beattie, and Bresnahan scores in the combination group was higher than the other groups (P<0.05). 5-Bromo-2'-deoxyuridine positive cel s grew wel , and integrated into the normal spine;syringomyelia was reduced, and the number of spinal neural cel s was increased in the combination group. In addition, glial fibril ary acidic protein expression was decreased in the combination group, while matrix metal oproteinase 2 expression was increased. It indicates that low-frequency electromagnetic fields could promote recovery of motor function in the spinal cord injury rats transplanted with bone mesenchymal stem cel s, which could be associated that low-frequency electromagnetic fields facilitate the survival of transplanted bone mesenchymal stem cel s, up-regulate the expression of matrix metal oproteinase 2, and reduce glial scar formation in the spinal cord injured site.
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BACKGROUND: Telomerase can maintain the telomere length and avoid cel replicative senescence and apoptosis in somatic cells. Its catalytic subunit cal ed telomerase reverse transcriptase has roles in mediating cellsurvival and anti-apoptotic functions. OBJECTIVE: To evaluate the effects of human telomerase reverse transcriptase on amyloid β1-40-induced human embryonic cortical neurons injury. METHODS: Human cortical neurons derived from 12-16 weeks old aborted fetuses were transfected with recombinant adenovirus vector encoding human telomerase reverse transcriptase. Expression of human telomerase reverse transcriptase was evaluated by immunocytochemical staining. Telomerase activity was measured using a PCR-based telomeric repeat amplification protocol enzyme-linked immunosorbent assay kit. Human embryonic cortical neurons were treated with 10 μmol/L ol/L amyloid β1-40 after transfected for 3 days. Cel viability, reactive oxygen species levels and glutathione contents in human embryonic cortical neurons were respectively detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate and chromatometry. RESULTS AND CONCLUSION: Expression of human telomerase reverse transcriptase reached peak at 3 days after transfection, and the telomerase activity was rebuilt; 10 μmol/L amyloid β1-40 could significantly reduce the cel viability of neurons and glutathione content (P < 0.05 and P < 0.01), and increase the reactive oxygen species levels (P < 0.05). The neurons transfected with human telomerase reverse transcriptase gene could be significantly against the toxicity of amyloid β1-40 and increase the cel viability and glutathione content (P < 0.05 and P < 0.01), and decrease the reactive oxygen species levels (P < 0.05). The results indicate that human telomerase reverse transcriptase can protect amyloid β1-40-induced human embryonic cortical neurons injury
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BACKGROUND: It is difficult to in vitro isolate and culture the ovarian surface epithelium with high purity, strong vitality and stable biological characteristics. Tissue adherence and enzymatic digestion are commonly used for primary culture, but there are certain problems in cel col ection, cel viability and cel purity. OBJECTIVE: To establish a method for primary isolating, culturing and identifying human ovarian epithelium. METHODS: The ovarian surface epithelium was obtained with cel brush innovatively, and then the cells were isolated and purified with erythrocyte spal ation and differential adherence. The epidermal growth factor was added into the serum-free Dulbecco’s modified Eagle’s medium-F12 medium for cel culture. The cel morphology was observed under inverted microscope, and hematoxylin-eosin staining and immunocytochemical staining were used to identify the cells, then the growth curve was draw. RESULTS AND CONCLUSION: The ovarian surface epithelium became adherent after cultured for 24 hours, and reached fusion basical y after cultured for 6-12 days. The cells were polygonal or flat with strong transparency and refraction. The morphological characteristics of the cells were in line with those of the normal epithelial cells, and almost al the isolated cells could express the epithelial cells surface marker CK19. The cells could be passaged for 6-8 generations with wel growth and the cel growth curve was in “S” shape. The purity of the cells was more than 95%. The results suggest that cel brush method is simple to operate and can obtain a large amount of ovarian surface epithelium rapidly. The purity of the isolated cells can reach to 95% after treated with erythrocyte spal ation and differential adherence method and the cells are in stable growth.
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BACKGROUND:Preparation of titanium/hydroxyapatite composite by conventional methods has the deficiency of simple structure, low degree of automation and difficulty in porosity and pore size control, which limits the diverse process and manufacture. OBJECTIVE:To evaluate the feasibility of three-dimensional printing technology for the preparation of titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded material molding. METHODS:A CAD model of titanium/hydroxyapatite composite was designed to be the cylinder (diameter 25 mm, height 20 mm), while the titanium/hydroxyapatite functional y graded implant designed as a CAD model of the cylinder with 25 mm in diameter asnd 10 mm in height with two layers, the upper layer with titanium powder and the lower layer with titanium/hydroxyapatite powder. The composite and functional y graded implant were processed by the three-dimensional printing and sintered. The sintered titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded implant were observed for their microstructures, and the X-ray diffraction analysis and compressive strength testing were performed. RESULTS AND CONCLUSION:The sintered titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded implant had uniform contraction and no obvious distortion. The sintered titanium/hydroxyapatite composite had the aperture size from 50 to 150μm. There occurred a chemical reaction between titanium and hydroxyapatite during the sintering process, obtaining the new creations of Ca3(PO4)2, CaTiO3, TiO2 and CaO. Its compressive strength was (184.3±27.1) MPa. The microstructure of titanium/hydroxyapatite functional y graded implant had graded structures with a visible line between the two layers. The results of the microstructure and mechanical properties of titanium/hydroxyapatite composite and titanium/hydroxyapatite functional y graded implant can meet the requirements of medical biological implant materials.
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BACKGROUND:Periodontal tissue engineering technology provides new ideas and new ways for periodontitis-induced bone defect repair. OBJECTIVE:To develop a culture model for the periodontal ligament cells of miniature swine, which was constructed with hydroxyapatite, to investigate the biocompatibility with hydroxyapatite. METHODS:Periodontal ligament cells from miniature swine were harvested by using tissue explant method. Immunofluorescence was used to detect the expression of stromal cel antigen 1 in the periodontal ligament cells of miniature swine. The third passage cells were co-cultured with a three-dimension hydroxyapatite scaffold, and the biological characteristics of the cells were observed under a scanning electron microscope at days 1, 3, 7 of co-culture. RESULTS AND CONCLUSION:The pirmary miniature swine periodontal ligament cells grew wel , and they were positive for stromal cel antigen 1. Under the scanning electron microscope, the periodontal ligament cells of miniature swine grew wel on the hydroxyapatite scaffold at days 1, 3, 7 of co-culture. These prove that the miniature swine periodontal ligament cells, which can be separated using tissue explant method and cultured successful y in vitro, can grow wel on the hydroxyapatite scaffold.
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BACKGROUND:Silk fibroin, chitosan, and nano hydroxyapatite are natural materials, and they al have good biological activity and physical or chemical properties. As tissue engineering materials, they have been already widely used in clinic or research work, but there are some defects in the application of these three kinds of materials. OBJECTIVE:To discuss the preparation and characteristics of silk fibroin/chitosan/nano hydroxyapatite complicated scaffolds which could be used in bone tissue engineering. METHODS:Silk fibroin, chitosan, and nano hydroxyapatite were separately prepared into 2%solution, and then mixed at the ratio of 1:1:0.5, 1:1:1, 1:1:1.5 respectively. The three-dimensional complicated scaffolds were prepared by those mixed liquids through repeated freeze drying and chemical crosslinking technology. Scanning electron microscope was used to detect the pore size of the scaffolds. Porosity, water absorption rate, and hot-water loss rate were determined. Mechanical tester was used to measure the tensile and compressive modulus of dried three-dimensional scaffolds. RESULTS AND CONCLUSION:The silk fibroin/chitosan/nano hydroxyapatite complicated scaffold in the dry state had no special smel , appeared to be a stabilized solid cylinder, and exhibited clear resiliency and flexibility with a touch. With the increased content of nano hydroxyapatite, the porosity, water absorption rate and average pore size of the scaffolds appeared to be decreased, while the hot-water loss rate and compressive strength were increased. The scaffold prepared at 1:1:1 was better for bone tissue engineering, and the average pore size, water absorption rate and hot-water loss rate were 85.67 μm, (135.65±4.56)%and (22.84±1.06)%, respectively, closer to the needs of the bone tissue engineering. Uniform pores were found within the scaffold at 1:1:1, showing the network structure, developed transport among pores, and the network structure was approximately 10μm.
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BACKGROUND:Vertebral metastatic tumor often occurs in the thoracolumbar segment, and it is difficult for internal fixation due to the complex anatomical position. OBJECTIVE:To evaluate the stability of lumbar vertebra in the patients with single thoracolumbar vertebral metastases after treated with artificial vertebral placement and internal fixation. METHODS:Sixteen patients (9 male and 7 female) with single thoracolumbar vertebral metastases treated in the Department of Orthopedics, the Fourth Hospital of Hebei Medical University from January 2006 to January 2009 were selected, and the age ranged 40-74 years, averaged 52 years. Before treatment, al the patients were evaluated according to Frankel classification:A grade in two cases, B grade in three cases, C grade in three cases, D grade in five cases, and E grade in three cases. And the vertebral state of patients was detected with X-ray plain film examination, systemic radionuclide bone scanning, CT and MRI. The T11 vertebral metastases were treated with chest approach artificial vertebral placement and internal fixation, and T12-L2 vertebral metastases were treated with artificial vertebral placement and internal fixation via extrapleural and extraperitoneal space approach. RESULTS AND CONCLUSION:Al the 16 patients were fol owed up for 4-32 months, and the average survival time after treatment was 12 months. After treatment, Frankel classification was C grade in three cases, D grade in five cases and E grade in eight cases. The visual analog scale score was decreased from (6.22±1.31) before treatment to (3.25±0.94) after treatment, and there was significant difference between two groups (P<0.05). The artificial vertebral placement and internal fixation can restore the stability of lumbar vertebra in the patients with spinal metastases, and thus improving the symptoms and quality of life.
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BACKGROUND:Previous studies have found that the susceptibility genes of adiponectin gene and calpain 10 gene of type 2 diabetes are closely related with the incidence of diabetes in Chinese renal transplantation patients. So, are other susceptibility genes of type 2 diabetes also associated with posttransplantation diabetes mel itus? OBJECTIVE:To investigate the association between the zinc transporter solute carrier family 30 member 8 (SLC30A8) gene polymorphism and the posttransplantation diabetes mel itus. METHODS:A total of 97 patients with posttransplantation diabetes mel itus and 301 patents without posttransplantation diabetes mel itus (control group) were selected, and then the SLC30A8 gene rs13266634 genotype was detected with real-time PCR method. The association between gene polymorphism and posttransplantation diabetes mel itus was analyzed with Logistic regression test. RESULTS AND CONCLUSION:There were significant differences in al ele frequencies and genotype distributions of rs13266634 between the patients with and without posttransplantation diabetes mel itus (P<0.05). After adjustments of age, sex, body weight and body mass index, the incidence of posttransplantation diabetes mel itus of the CC genotype patients was 2.108 times to that of the TT genotype patients (odds ratio=2.108, 95%confidence interval:1.075-4.131, P=0.044);and the incidence of posttransplantation diabetes mel itus of the CC+CT genotype patients was 1.862 times to that of the TT genotype patients (odds ratio=1.862, 95%confidence interval:1.049-3.306, P=0.034). The results suggest that the C-al ele in rs13266634 of SLC30A8 gene is the independent risk factor of posttransplantation diabetes mel itus.
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BACKGROUND:Cel transplantation offers a new promise of rebuilding the damaged myocardium. But the results of them are not consistent. It is not clear if the transplanted cel s can permanently improve heart function and the mechanism underlying this therapeutic effect. OBJECTIVE:To study the effect of intracoronary autologous bone marrow mononuclear cel transplantation on cardiac function, and angiogenesis and cytokine production in canines with acute myocardial infarction. METHODS:Left anterior descending coronary artery ligation was used to produce acute myocardial infarction models in hybrid canines. Bone marrow mononuclear cel s were harvested by using puncture of anterior crest and posterior superior iliac spine to prepare cel suspension. Sixteen hybrid canines were randomly divided into transplantation group (n=10) and control group (n=6). Bone marrow mononuclear cel s (transplantation group, n=10) or normal saline (control group, n=6) were intracoronarily infused into infarction-related arteries 2 hours after acute myocardial infarction. To evaluate the heart function, we used echocardiography at 2 hours and 6 weeks after acute myocardial infarction. Capil ary density was assessed 6 weeks after transplantation by using von Wil ebrand factor test. The mRNA levels of vascular endothelial growth factor 188, vascular endothelial growth factor 164, basic fibroblast growth factor and matrix metal oproteinase-9 in the infarct area were determined by reverse transcription-PCR at 6 weeks after transplantation. RESULTS AND CONCLUSION:In contrast to the control group, ejection fraction and stroke volume at 6 weeks after transplantation increased significantly in the transplantation group. The transplantation group had a greater amount of new vessels in the peri-infarct area than the control group. Compared with the control group, the mRNA levels of vascular endothelial growth factor 188, vascular endothelial growth factor 164, and basic fibroblast growth factor significantly increased in the transplantation group, but the mRNA level of matrix metal oproteinase-9 significantly decreased in the transplantation group. These findings suggest that intracoronary transplantation of autologous bone marrow mononuclear cel s may improve the cardiac function, and increase capil ary density, especial y in the border zone of infarcted myocardium. Otherwise, bone marrow mononuclear cel transplantation can increase the mRNA levels of vascular endothelial growth factor 188, vascular endothelial growth factor 164, and basic fibroblast growth factor, but decrease the mRNA level of matrix metal oproteinase-9.