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OBJECTIVE@#To evaluate the efficacy and safety of hydroxychloroquine (HCQ) in the treatment of patients with moderate coronavirus disease 2019 (COVID-19).@*METHODS@#We prospectively enrolled 30 treatment-naïve patients with confirmed COVID-19 after informed consent at Shanghai Public Health Clinical Center. The patients were randomized 1:1 to HCQ group and the control group. Patients in HCQ group were given HCQ 400 mg per day for 5 days plus conventional treatments, while those in the control group were given conventional treatment only. The primary endpoint was negative conversion rate of SARS-CoV-2 nucleic acid in respiratory pharyngeal swab on days 7 after randomization. This study has been approved by the Ethics Committee of Shanghai Public Health Clinical Center and registered online (NCT04261517).@*RESULTS@#One patient in HCQ group developed to severe during the treatment. On day 7, nucleic acid of throat swabs was negative in 13 (86.7%) cases in the HCQ group and 14 (93.3%) cases in the control group (>0.05). The median duration from hospitalization to virus nucleic acid negative conservation was 4 (1,9) days in HCQ group, which is comparable to that in the control group [2 (1,4) days, Z=1.27, >0.05]. The median time for body temperature normalization in HCQ group was 1 (0,2) day after hospitalization, which was also comparable to that in the control group [1 (0,3) day]. Radiological progression was shown on CT images in 5 cases (33.3%) of the HCQ group and 7 cases (46.7%) of the control group, and all patients showed improvement in follow-up examinations. Four cases (26.7%) of the HCQ group and 3 cases (20%) of the control group had transient diarrhea and abnormal liver function (>0.05).@*CONCLUSIONS@#The prognosis of COVID-19 moderate patients is good. Larger sample size study are needed to investigate the effects of HCQ in the treatment of COVID-19. Subsequent research should determine better endpoint and fully consider the feasibility of experiments such as sample size.
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Humans , Betacoronavirus , China , Coronavirus Infections , Diagnostic Imaging , Drug Therapy , Hydroxychloroquine , Therapeutic Uses , Pandemics , Pilot Projects , Pneumonia, Viral , Diagnostic Imaging , Drug Therapy , RNA, Viral , Treatment OutcomeABSTRACT
Objective:To explore the protective effect of exosomes secreted from bone mesenchymal stem cells (BMSCs)modified by hypoxia inducible factor-1α(HIF-1α)on the chondrocytes,and to elucidate the possible mechanism of its combination with cartilage regenerated scaffolds in promoting the repair of advanced cartilage defects.Methods:The exosomes(BMSCs-ExoWTand BMSCs-ExoMU)were extracted from the BMSCs modified by wild type of HIF-1α and mutant type of HIF-1α by ultracentrifugation method and identified in the meantime.In vitro the inflammatory response of chondrocytes were induced by interleukin-1β(IL-1β),the same amount of PBS, BMSCs-ExoWT(80 μg · mL-1),BMSCs-ExoMU(80 μg · mL-1)were respectively cultivated with the chondrocytes under the inflammatory reaction and blank group,inflammation group,BMSCs-ExoWTgroup and BMSCs-ExoMUgroup were set up;Hoechst33342 staining was used to detect the number of apoptotic bodies of chondrocytes in various groups.The Western blotting method was used to detect the expression levels of AKT/p-AKT,ERK/p-ERK and p38/p-p38 in the chondrocytes in various groups.Twelve New Zealand white rabbits were randomly divided into 4 groups and the models of rabbit knee cartilage defects were consructed;the equal volume of physiological saline,scaffold +physiological saline,scaffold +BMSCs-ExoWTand scaffold +BMSCs-ExoMUwere respectively injected into the cartilage defects of rabbits.Six weeks after operation,gross conference, HE and safranin O staining were used to observe and compare the repair effects of cartilage defects in each group. Results:BMSCs-ExoWTand BMSCs-ExoMUwere successfully extracted and identified,and the exosomes were observed to be nearly circular with diameter of about 40-100 nm;the Western blotting results showed that they expressed special proteins CD63 and CD81,respectively.In vitro,the number of apoptotic bodies of chondrocytes in BMSCs-ExoMUgroup was lower than those in inflammation group and BMSCs-ExoWTgroup(P<0.01).The Western blotting results revealed that the expression levels of p-ERK1/2 in BMSCs-ExoMUand BMSCs-ExoWT groups were lower than that in inflammation group(P<0.05);the expression levels of p-AKT and p-p38 were higher(P<0.05);the effect in BMSCs-ExoMUgroup was stronger than BMSCs-ExoWTgroup,and the difference was statistically significant(P<0.05).In the advanced cartilage defect models of rabbit knee joint,the repair effect in scaffold+ BMSCs-ExoMUgroup was better than those in blank group,scaffold group and scaffold+BMSCs-ExoWTgroup.Conclusion:Cartilage scaffold combined with BMSCs-ExoMUcan promote the repair of cartilage defects.
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Objective:To explore the effects of exosomes derived from bone-marrow endothelial progenitor cells(EPCs-Exos)on the angiogenesis and collagen deposition in vitro,and to illustrate the possible mechanism for EPCs-Exos to accelerate the cutaneous deficiency repair.Methods:The endothelial progenitor cells (EPCs) were isolated, cultivated and identified;at the same time, the EPCs-Exos were also isolated and identified.The EPCs-Exos uptake in EPCs was observed and analyzed.16 rats were randomly divided into 4 groups, and then the models of skin defect were established, respectively.The equal volume of PBS and 50, 100, 150 mg·L-1 EPCs-Exos were injected into the area around skin defect of the rats in 4 groups.The wound closed sizes on the 0, 3rd, 7th and 14th days were measured, and Masson''s trichrome staining and CD31 immunofluorescence staining were performed on the 14th day for evaluating the tissue healing efficacy after EPCs-Exos treatment.In vitro,the mediums containing PBS and 50, 100, 150 mg·L-1 EPCs-Exos were used to culture the human umbilical vein endothelial cells (HUVECs), respectively.Scratch test and tubule formation assay were used to detect the migration and capillary network formation of HUVECs.At the same time, Western blotting was used for analyzing the expression level of angiogenesis related gene vascular endothelial growth factor A (VEGFA) in HUVECs.Results: The primary EPCs were isolated and identified successfully, and EPCs-Exos were purified and characterized.The CD31 immunofluorescence staining and double staining of DiL-ac-LDL and FITC-UEA-I of EPCs were positive.The electron microscope results showed that EPCs-Exos were nearly spheroidal, with the diameter about 40-100 nm.For the models of rat skin injury treated by EPCs-Exos, with the increasing of injection doses, the sizes of skin defect scar were gradually reduced, the degrees of scar healings were gradually increased,and the differences between various groups were statistically significant (P< 0.05).EPCs-Exos promoted the collagen maturity of healing skin in a dose-dependent manner;on the 14th day, the effect in 150 mg·L-1 EPCs-Exos group was the most significant.In vitro, EPCs-Exos promoted the migration and capillary network formation of HUVECs and increased the expression level of VEGFA;the migration rate,the net number of branches and the expression level of VEGFA in 150 mg·L-1 EPCs-Exos group were significantly higher than those in 50 mg·L-1 EPCs-Exos group and PBS group (P< 0.05).Conclusion: EPCs-Exos can promote the repair of traumatic skin defect of the rats by positively regulating the vascular endothelial cell function.
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BACKGROUND:The self-renew and regeneration capacity of the injured spinal cord is thought to be limited. Accordingly, cel transplantation is one potential strategy for promoting functional recovery after spinal cord injury. OBJECTIVE:To explore the effects ofPTEN silencing on the biological properties of bone marrow mesenchymal stem cels, hoping to offer better seed cels for tissue engineering. METHODS:Bone marrow mesenchymal stem cels were transfected with specific siRNA-silencedPTEN gene using the liposome method, and then RT-PCR was used to detect the mRNA expression ofPTEN. Variation of biological properties ofPTEN-transfected cels were detected by the way of MTT assay, cel cycle analysis, and Transwel assay. RESULTS AND CONCLUSION:PTEN is expressed highly in bone marrow mesenchymal stem cels, which is successfuly interfered by siRNA.PTEN-silenced cels have stronger survival, proliferation and migration abilities, which become a kind of better seed cels for tissue engineering.
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<p><b>OBJECTIVE</b>To explore the psychometric performances and applicability of SF-36v2 in assessment quality of life among urban residents in Chengdu.</p><p><b>METHODS</b>During Oct. to Dec., 2012, 2 186 adult urban residents with clear mind and well self-express were recruited in the study by multistage stratified cluster sampling method in Chengdu urban area. The survey questionnaires included general health condition and quality of life, which was adopted the SF-36v2. Internal consistency reliability, test-retest reliability and construct validity were all analyzed as indicators of the psychometric performance.</p><p><b>RESULTS</b>The survey released 2 186 questionnaires, with 2 182 ones returned and 2 178(99.8%) met the data standard. The scores of 8 scales in SF-36v2, including physical function (PF), role-physical (RP), bodily pain (BP), general health (GH), vitality (VT), social function (SF), role-emotion (RE) and mental health (MH), were 89.15 ± 17.56, 85.18 ± 22.52, 76.64 ± 17.80, 64.13 ± 19.56, 70.39 ± 17.31, 86.43 ± 17.35, 87.79 ± 19.24 and 80.61 ± 13.49, respectively; the floor effects were 0.28%, 0.41%, 0.23%, 0.28%, 0.09%, 0.05%, 0.14% and 0.23%, respectively; and the ceiling effects were 51.38%, 60.60%, 58.08%, 0.83%, 2.94%, 50.32%, 64.00% and 3.95%, respectively. The item-convergent validities were all achieved the standard (r = 0.40) except the item MH5 (Have you been happy?), and the total scaling success rate of item-convergent validity was 97.14%. The scales' success rates of item-discriminant validities for the SF, VT and MH scales were 93.75%, 56.25% and 97.50% respectively, while the rates of others were 100.00% and the total success rate was 96.43%. The internal reliability ranged from 0.724 to 0.974 across all the scales, except for SF (r = 0.603) and VT (r = 0.697). The two-week test-retest reliability ranged from 0.610 to 0.845. Within factor analysis, two common factors were confirmed, separately representing physical health and mental health, altogether contributing 64.4% of the total variance.</p><p><b>CONCLUSION</b>As a revised version of SF-36v1, the SF-36v2 seemed to be more preferable in layout for questions and answers and could reduce the ceiling and floor effect. Additionally, it also showed comparatively well reliability and validity. And thereby we believed the SF-36v2 could be applied to assess the life quality among urban residents in Chengdu.</p>
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Adult , Humans , China , Data Collection , Factor Analysis, Statistical , Health Surveys , Psychometrics , Quality of Life , Reproducibility of Results , Research Design , Surveys and Questionnaires , Urban PopulationABSTRACT
Objectives To learn about current public health education for undergraduate clinical students and to provide some references for developing suitable teaching way in the further.Methods Public health education for undergraduate clinical students in 11 medical colleges and universities and teachers' opinions on it were surveyed with the self-made questionnaire.Quantitative data were analyzed with descriptive statistic method.Results All the surveyed colleges and universities opened public health curriculum for undergraduate clinical students and 10 colleges and universities made public health course to be compulsory.The teaching contents were varied in different colleges and universities.Teachers who gave the public health courses proposed some suggestions on its reform.Conclusions Public health education for clinical students in different colleges and universities has both unity and diversity.It should develop new teaching model based on the training goal of public health education for undergraduate clinical students.
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BACKGROUND: Vascular endothelial growth factor (VEGF) can promote angiogenesis, and has been extensively used in treatment of bone defect. However, few studies have addressed its isomer VEGF121. OBJECTIVE: To construct adenovirus vector carrying VEGF121-FLAG and humanized Renilla reniformis green fluorescent protein 1(hrGFP-1) and observe its expression in bone marrow stromal stem cells (BMSCs). METHODS: Using polymerase chain reaction technique, VEGF121 gene contained in the plasmid of pTG19T-VEGF121 was used to remove termination codon. NotI and Xho I restriction sites were added before and after gene sequence. Obtained gene subclone was moved onto pMD19-T plasmid. The pMD19-T-VEGF121 and pShuttle-CMV-IRES-hrGFP-1 plasmids underwent double enzymatic digestion. Small fragment and big fragment were retrieved utilizing gel. Subsequently, coupled reaction was conducted to complete the construction of shuttle plasmid. After measuring virus titer, BMSCs were transfected and the fluorescence intensity was observed under fluorescence microscope.RESULTS AND CONCLUSION: Recombinant adenovirus plasmid was successfully constructed by enzymatic digestion determination and gene sequence. Fluorescence microscope has shown that BMSCs transfected with recombinant adenovirus presented significantly green fluorescence expression. Thus, adenovirus vector carrying VEGF121-FLAG and hrGFP-1 gene can express in eukaryotic cells, which can be used for gene therapy for ischemic disease.
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BACKGROUND: Hypoxia-inducible factor-1 (HIF-1) can regulate the co-expression of various genes, and can induce angiogenesis with integrated physiological function.OBJECTIVE: To construct a novel adenoviral eukaryotic expression vector that can co-express mutant hypoxia-inducible factor-1 alpha (HIF-1a) target protein and humanized Renilla reniformis green fluorescent protein (hrGFP) reporter molecule under normoxic conditions.METHODS: The human HIF-1α gene carried by target gene donor plasmid pCMV6-XL5-HIF1α was sequenced and the site of restriction enzyme in above gene was analyzed. Site-directed mutagenesis of three amino acids including the 402 location, the 564 location, and the 803 location in gene coding region in HIF-1α were performed by polymerase chain reaction and sequencing was also done for monitoring mutation. The HIF-1α gene mutated correctly (HIF-1αmu) was coupled to adenoviral shuttle vector pShuttle-CMV-IRES- hrGFP-1. The recombinant adenovirus shuttle vector carrying HIF-1αmu gene was transferred to BJ5183-AD-1 electroporation competent cells after sequencing identification and Pme I restriction enzyme linearization.HIF-1αmu and hrGFP gene as well as hemeo-expression elements of hrGFP gene were reconstructed into adenoviral genome plasmids using homologous recombination mechanism in bacterium. Recombinants were obtained by Pac I restriction enzyme digestion and sequencing identification.RESULTS AND CONCLUSION: Amino acids including the 402 location, the 564 location and the 803 location in gene coding region in HIF-1α had become alanine after site-directed mutagenesis. Recombinant adenoviral expressing vector was successful as confirmed by restriction enzyme digestion and sequencing. These findings demonstrate that a novel recombinant adenoviral mutant eukaryotic expression vector pAd-HIF1αmu-IRES-hrGFP-1 was successfully constructed.
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BACKGROUND: Alginic acid has a relatively mild gel condition and good biocompatibility, and it has been widely used in bio-tissue engineering.OBJECTIVE: To construct bone tissue engineering scaffolds using alginate gel composite bone xenograft approach, and to observe the cell biological properties and in vivo osteogenic potential in scaffolds.METHODS: The bone marrow was harvested from two 2-week-old New Zealand rabbits, 1 ×10~(-8)mol/L recombinant human bone morphogenetic protein-2 was used to induce bone marrow mesenchymal stem cells. The induced bone marrow mesenchymal stem cells at the second generation were incubated into 1% sodium alginate gel, after cultured for 4 days, the cell morphology in gel was observed by hematoxylin-eosin staining. Bone marrow mesenchymal stem cells at the second generation were divided into simple DMEM gel group and DMEM containing 1% sodium alginate gel group, followed by a culture of 7 days. Then bone morphogenic protein-2 immunohistochemical staining was performed. A total of 24 nude mice were randomly divided into two groups, both sides of the thigh muscle pockets were implanted with bone marrow-derived mesenchymal stem cells/alginate gel/bovine cancellous bone complex as an experimental group, with bone marrow-derived mesenchymal stem cells/bovine cancellous bone as a control group. At 2 and 4 weeks post-operation, the osteogenesis in the composite was observed by histological examination, the percentage area of new bone or cartilage was determined using image analysis system.RESULTS AND CONCLUSION: The bone marrow-derived mesenchymal stern cells in the sodium alginate gel exhibited a well-stacked morphology, they suspended in a gel, showing cell division and mitosis phase. In the simple DMEM gel group and DMEM gel containing 1% sodium alginate group, the immunohistochemical results showed that, cell division and proliferation were normal, with prominence at a variety of forms, large nucleus, and clear nucleolus. The bone morphogenetic protein-2 expression had no significant difference between the simple DMEM gel group and DMEM gel containing 1% sodium alginate group (P>0.05).Scanning electron microscopy revealed that, the alginate gel evenly composited in bovine cancellous bone micropores, cell grew at different planes. Animal experiments showed that there were significant differences regarding the percentage of new bone or cartilage area between the experimental group and control group at 2 and 4 weeks postoperation (P< 0.05). It is indicated that constructing bone tissue engineering scaffolds by using alginate gel/bovine cancellous bone, complies with the ultra-structural principle of tissue engineering scaffolds, can maximize the cell loads, achieve good bio-performance, without adverse affects on the proliferation, osteogenic phenotype and related biological properties of bone marrow-derived mesenchymal stem calls, the in vivo osteogenic efficiency was high.
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BACKGROUND: Anterior cruciate ligament (ACL) is the kernel of articular genu, for the past few years, the incidence rate of cruciate ligament injury increased gradually.OBJECTIVE: To review on the mechanism of the injury of ACL, the method of operation, the election of transplant, the reconstruction of equilong, the reconstruction of ligament and so on, and to look forward to providing some references on treating the ACL injury.METHODS: A computer-based research was conducted in Medine database (1996-01/2009-03), with the key words of "Anterior cruciate ligament, implant, reconstruction, repair". Chongqing VIP database and Qinghua Tongfang database (1996-01/2009-03) were retrieved with the same key words.RESULTS AND CONCLUSIONS: 200 literatures on arthroscopic ACL reconstruction were collected, excluding older, repeated and similar research, and the 18 standard literatures were included. ACL is a key structure to stabilize knee joint, and exercises and various factors during daily life could induce its injury. Unsuitable treatment would severely affect movement ability or movement loss. To recover structure and function of knee joint, damaged ACL should be reconstructed. With the development of technique and innovation of surgical instrument, arthroscopic reconstruction has presently been a popular method to treat ACL. There are many methods to treat ACL injury, but none of them can duplicate ACL anatomical relationship. It is still in doubt whether the operation can reduce the secondary damage. We have much more work to research on modus operandi, implant, postoperative rehabilitation and other adjunctive therapies.
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The vaseularization of tissue-engineered bone is the key problem which the development and employment of large sized tissue-engineered bone.The vascular endothelial cell has a great effect on promoting vascularization in tissue-engineered bone.Vascularizations fall into two modes of vaseulogenesis and angiogenesis according to differences in source of endothelial cells.Co-culture of osteoblasts and vascular endothelial cells has better result than single culture of each kind of cells.Different ways of improving the vascularization,such as searching for new source of vascular endothelial cell,co-culture and in vivo experiment are investigated to meet the challenge of bone tissue engineering.
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BACKGROUND: Whether bone morphogenetic protein 2 (BMP-2) can be transduced into marrow stromal cells (MSCs) and produce osteogenic effects by viral or non-viral vector remains unclear? OBJECTIVE: To observe the expression of cultured rabbit MSCs transfected with pcDNA3-hBMP2 in vitro. Simultaneously, the MSCs were transfected but not screened and then transplanted into autologous muscle to investigate the osteogenic capability by X-ray. DESIGN, TIME AND SETTING: A controlled observation experiment was performed at the Department of Orthopedics, Liaoning Medical University between November 2004 and April 2005. MATERIALS: Six adult New Zealand rabbits, of either gender, weighing 2.0-3.0 kg, were included for this study. BMP2 antibody was the product of Sanaka Company, USA. pcDNA3-hBMP2 was provided by Professor Pu Qin from the Department of Biochemistry, Fourth Military Medical University of Chinese PLA). Restriction enzyme was purchased from Takara biotechnology (Dalian) CO., LTD., China. METHODS: Super-purified plasmid pcDNA3-hBMP2 was extracted from E. coli. Bone marrow was taken from the adult rabbit femur for harvesting MSCs by density gradient separation. The MSCs were divided into the following 4 groups: Group A, cells were transfected and screened by G418; Group B, cells were transfected by pcDNA3-hBMP2; Group C, cells were transfected by empty vector pcDNA3; Group D, only transfection reagent Fugene 6 was added.MAIN OUTCOME MEASURES: Transient BMP2 expression was analyzed by immunohistochemistry. Expression of osteocalcin and collagen I was examined by immunohistochemistry and in situ hybridization, respectively. Two weeks after transfection, MSCs from the group B were autologously transplanted into the muscle. Four weeks later, X-ray assay was used to observe bone formation.RESULTS: pcDNA3-hBMP2 was successfully transduced into MSCs and transiently expressed BMP2 100%. Four weeks after gene transfection, expression levels of osteocalcin and collagen I were significantly higher in the group A than in the groups C and D. X-ray results demonstrated new bone formation four weeks after MSCs transplanted into the muscle.CONCLUSION: pcDNA3-hBMP2 can safely and efficiently transfect MSCs and induce them to differentiate towards osteoblasts by secreting BMP2.
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BACKGROUND:The structure of tissue engineering carrier affects the bio-action of cells greatly.OBJECTIVE: To investigate the biological characteristics of bone marrow stem cells (MSCs) in different concentrations of alginate combined with de-antigen bone xenograft (DBX).DESIGN: Observational trial.SETTING: PLA Institute of Trauma and Orthopedics, the Fourth Military Medical University of Chinese PLA.MATERIALS: Alginate, calcium chloride, MSCs, bone xenograft.METHODS: Bovine cancellous bone was out into cubes, which were degreased, deproteinized and then lyophilized.Cubes in pore size within 300-500 μm were selected for use after ethylene oxide sterilization. The purified sodium alginate was dissolved in DMEM cell culture medium of concentrations as different as 0.5%, 2%, 8% and 16%; 1×1012 L-1 induced MSCs were blended with isopyknic alginate-DMEM and compounded with DBX at a status of 0.5 Mpa negative pressure for 5 minutes in order to make a cell suspension fully fill into the pores of the cancellous bone. Then alginate was crosslinked with 50 g/L calcium gluconic acid for 30 seconds. The complex was put into a CO2 incubator and cultured for 4 days. The gel compound and cell growth in the pores of the complex were grossly observed with an inverted microscope. Status of cell growth in the complex with different concentrations of alginate was observed with scanning electron microscopeMAIN OUTCOME MEASURES: Compound status of alginate and bone xenograft, cell growth status and matrix secretion in compound carries.RESULTS: When the concentration of alginate was 0.25% or 1%, alginate was equally combined in DBX, while that of 4% and 8% only combined on the surface of cancellous bone. After in vitro cultured for 4 days, alginate of 0.25% were broken off from DBX surface. But alginate of 1% was equally combined with DBX pores with cells secreting well in alginate. Development of cells in alginate of 4% was restricted and no cells were seen in alginate of 8%.CONCLUSION: Alginate of 1% is suitable for constructing the carrier of bone tissue engineering with bone xenograft.
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BACKGROUND: It has been verified vascular endothelial cells can propagate and differentiate into vessel by planted in the tissue-engineered material in vivo, but it may cause severe trauma when obtain vascular endothelial cells, and it has limited sources. OBJECTIVE: To investigate whether bone marrow mesenchymal stem cells (BMSCs) can differentiate into vascular endothelial cells by combined induction of vascular endothelial cell growth factor (VEGF), basic fibroblast growth factor (bFGF) and insulin-like growth factor (IGF)-1 by experimental observation. DESIGN, TIME AND SETTING: The control cell observation experiment was conducted at the Central Laboratory of First Affiliated Hospital, Liaoning Medical University from November 2006 to June 2007. MATERIALS: An 8-week-old Japanese big ear rabbit was used to isolate BMSCs. VEGF, bFGF and IGF-1 were purchased from Peprotech Company. METHODS: After anaesthesia, bone marrow was extracted from the rabbit. Enough BMSCs were harvested by adherence and trypsinization and randomized into two groups. BMSCs in the induction group were inoculated in DMEM supplemented with 10% fetal bovine serum (FBS), 10 ?g/L VEGF, 1 ?g/L bFGF and 2 ?g/L IGF-1 for 2 weeks. BMSCs in the control group were inoculated in DMEM containing 10% FBS. MAIN OUTCOME MEASURES: Morphological observation, nitric oxide (NO) content detected, immunohistochemistry staining of Ⅷ factor-related antigen and Weibel-Palade body under a electron microscope in BMSCs. RESULTS: Five days after induction, BMSCs were distributed in cluster, showing round. Non-induced BMSCs were evenly distributed, showing spindle or triangle. Fourteen days after induction, NO content in supernatant was significantly higher in the induction group than in the control group (t=3.75, P
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Bone defect repair is a complicated process of connective tissue repair under the control of various cytokines.It is the ample blood supply which is a necessary condition to promote regeneration of fracture,especially bone defect and nonunion.Hypoxia inducible factor 1 can induce formation of neovascularization with perfect physiological function in the lesion of bone defect by regulating various gene expression,and thus provide nutritional support and favorable conditions to metabolism for different cells in the process of osteogenic differentiation and osteogenic activity to promote the healing of fracture.Both gene therapy and using hypoxia inducible factor 1 directly have an ability to promote neovascularization in the lesion of fracture.It is a hotspot at present that hypoxia inducible factor 1 in the field of bone tissue engineering is used to treat bone defect.Hypoxia inducible factor 1 transgenic therapy needs further research in the repairing process of bone defect.
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With the emergence of tissue engineering techniques, using tissue engineering methods and tools to repair cartilage defects become a new treatment model, while looking for a suitable carrier of chondrocytes is the current focus of the study in cartilage tissue engineering. In this paper, synthetic biodegradable polymers and natural extracellular matrix substitutes (natural polymers) make progress in two areas reviewed.