摘要：Long-segment defects remain a major problem in clinical treatment of tubular tissue *** design of tubular scaffold with desired structure and functional properties suitable for tubular tissue regeneration remains a great challenge in regenerative ***,we present a reliable method to rapidly fabricate tissueengineered tubular scaffold with hierarchical structure via 4-axis printing *** fabrication process can be adapted to various biomaterials including hydrogels,thermoplastic materials and thermosetting *** polycaprolactone(PCL)as an example,we successfully fabricated the scaffolds with tunable tubular architecture,controllable mesh structure,radial elasticity,good flexibility,and luminal *** a preliminary demonstration of the applications of this technology,we prepared a hybrid tubular scaffold via the combination of the 4-axis printed elastic poly(glycerol sebacate)(PGS)bio-spring and electrospun gelatin *** scaffolds seeded with chondrocytes formed tubular mature cartilage-like tissue both via in vitro culture and subcutaneous implantation in the nude mouse,which showed great potential for tracheal cartilage reconstruction.

摘要：Background tissue-engineering techniques combined with gene therapy have beenrecently reported to improve osteogenesis. In this study, tissue-engineered bone constructed byhuman Bone Morphogenetic Protein 4 (hBMP-4) gene-modified bone marrow stromal cells (bMSCs) wasexplored in an ectopic bone formation model in rabbits. Methods A pEGFP-hBMP-4 mammalian plasmid (EGFP: Enhanced Green Fluorescent Protein) was constructed by subcloning techniques. bMSCs obtainedfrom rabbits were cultured and transfected with either pEGFP-hBMP-4, pEGFP or left uninfected invitro. Transfer efficiency was detected through the expression of EGFP. Transcription of the targetgene was detected by RT-PCR. Alkaline phosphatase (ALP) and Von Kossa tests were also conducted toexplore the phenotypes of osteoblasts. The autologous bMSCs of the 3 groups were then combined withNatural Non-organic Bone ( NNB) , a porous hydroxyapatite implant with a dimension of 6 mm x 6 mm x3 mm, at a concentration of 5 x 10~7 cells/ml. They were subsequently implanted into 6 rabbitssubcutaneously using NNB alone as a blank control (6 implants per group). Four weeks after surgery,the implants were evaluated with histological staining and computerized analysis of new boneformation. Results pEGFP-hBMP-4 expression plasmid was constructed. Under optimal conditions, genetransfer efficiency reached more than 30% , Target gene transfer could strengthen the transcriptionof BMP-4, and increase the expression of ALP as well as the number of calcium nodules. In theectopic animal model, NNB alone could not induce new bone formation. The new bone area formed in thebMSCs group was (17.2 ± 7.1)%, and pEGFP group was (14.7 ± 6.1) % , while pEGFP-hBMP-4 group was(29.5 ± 8.2) % , which was the highest among the groups (F = 7.295, P < 0. 01). Conclusions Themammalian hBMP-4 expression plasmid was successfully constructed and a comparatively high transferefficiency was achieved. The gene transfer technique enhanced the expression of BM

摘要：Objective： Injury and deficiency of the lacrimal duct epithelium （LDE） can lead to a variety of lacrimal diseases. The purpose of this study was to characterize potential candidate cells for constructing a tissue-engineered LDE. Methods： Different areas of the conjunctiva and lacrimal duct tissue were removed from male adult New Zealand white rabbits for histological evaluation. Hematoxylin and eosin staining and immunohistochemical staining of cytokeratin AEI＋AE3, cytokeratin 4, Ki-67, and MUC5AC were observed by light microscopy. The surface morphologies of different epithelial tissues and cellular structures were examined using field-emission scanning electron microscopy and transmission electron microscopy. Epithelial cells were isolated from tissues and identified by specific markers. In vitro, proliferative ability and Western blot analyses of the proliferating cell nuclear antigen （PCNA） of different epithelial cells cultured in identical environments were investigated and compared. Results： Histologically, the epithelial specific markers, cytokeratin AEI＋AE3 and cytokeratin 4, were expressed in the conjunctiva epithelium and the LDE. Notably, highly proliferative cells stained with Ki-67 were concentrated under the epithelium in a dome structure of the posterior palpebral conjunctiva. Differentiated goblet cells were also found to a lesser extent in this region. Primary palpebral and fornical conjunctival epithelial cells （PFCECs）, bulbar conjunctival epithelial cells （BCECs）, and lacrimal duct epithelial cells （LDECs） were successfully separated from tissues. In vitro, rabbit PFCECs and LDECs grew faster and expressed more PCNA than BCECs. Conclusions： PFCECs are anatomically similar to LDECs. They also have similar morphological characteristics, immune phenotypes, and proliferation features. PFCECs are therefore potential candidate cells to replace LDECs in tissue engineering to treat lacrimal duct diseases.

摘要：Objective： In our previous work, we prepared a type of chitosan hydrogel with excellent biocompatibility. In this study, tissue-engineered cartilage constructed with this chitosan hydrogel and costal chondrocytes was used to repair the articular cartilage defects. Methods： Chitosan hydrogels were prepared with a crosslinker formed by combining 1,6-diisocyanatohexane and polyethylene glycol. Chitosan hydrogel scaffold was seeded with rabbit chondrocytes that had been cultured for one week in vitro to form the preliminary tissue-engineered cartilage. This preliminary tissue-engineered cartilage was then transplanted into the defective rabbit articular cartilage. There were three treatment groups： the experimental group received preliminary tissue-engineered cartilage; the blank group received pure chitosan hydrogels; and, the control group had received no implantation. The knee joints were harvested at predetermined time. The repaired cartilage was analyzed through gross morphology, histologically and immunohistochemically. The repairs were scored according to the international cartilage repair society （ICRS） standard. Results： The gross morphology results suggested that the defects were repaired completely in the experimental group after twelve weeks. The regenerated tissue connected closely with subchondral bone and the boundary with normal tissue was fuzzy. The cartilage lacuna in the regenerated tissue was similar to normal cartilage lacuna. The results of ICRS gross and histological grading showed that there were significant differences among the three groups （P〈0.05）. Conclusions： Chondrocytes implanted in the scaffold can adhere, proliferate, and secrete extracellular matrix. The novel tissue-engineered cartilage constructed in our research can completely repair the structure of damaged articular cartilage.

摘要：To get an optimal product of orthopaedic implant or regenerative medicine needs to follow trialand-error analyses to investigate suitable product’s material,structure,mechanical properites *** whole process from in vivo tests to clinical trials is expensive and *** model is seen as a useful analysis tool to make the product development.A series of models for simulating tissue engineering process from cell attachment to tissue regeneration are *** challenging is that models for simulating tissue engineering processes are developed *** cell to tissue regeneration,it would go through blood injection after moving out the defect;to cell disperse and attach on the scaffold;to proliferation,migration and differentiation;and to the final part-becoming mature *** paper reviewed models that related to tissue engineering process,aiming to provide an opportunity for researchers to develop a mature model for whole tissue engineering *** article focuses on the model analysis methods of cell adhesion,nutrient transport and cell proliferation,differentiation and migration in tissue *** cell adhesion model,one of the most accurate method is to use discrete phase model to govern cell movement and use Stanton-Rutland model for simulating cell *** for nutrient transport model,numerical model coupling with volume of fluid model and species transport model together is suitable for predicting nutrient transport *** cell proliferation,differentiation and migration,finite element method with random-walk algorithm is one the most advanced way to simulate these *** of the model analysis methods require further experiments to verify the accuracy and *** to the lack of technology to detect the rate of nutrient diffusion,there are especially few researches on model analysis methods in the area of blood ***,there is still a lot of work to be done in the resea

摘要：Objective ：To investigate the feasibility of using natural poritos as scaffolds in bone tissue engineering （TE） and repair of caprine mandibular segmental defect with titanium reticulum reinforced. Methods： Natural poritos with a pore of 190-230 μm in size and porosity of about 50 %-65 % was molded into the shape of granules 5 mm × 5 mm × 5 mm in size. Expanded autologous caprine marrow mesenchymal stem cells were induced by recombinant human morphogenetic protein-2 （rhBMP2） to improve osteoblastic phenotype. Then marrow derived osteoblasts were seeded into poritos in density of 4 × 10^7/ml and incubated in vitro for 48 hours prior to implantation. Then osteoblastic cells/poritos complexes were implanted into mandibular defect and the defect was reinforced by titanium reticulum. Implantation of poritos alone acted as the control. Bone regeneration was assessed 4, 8, 16 weeks after implantation using roentgenographie analysis and histological observation was done after 16 weeks. Results： New bone could be observed histologically on the surface and in the pores of natural coral in all specimens in the cell-seeding group, whereas in the control group there was no evidence of osteogenesis process in the center of the construction. The results showed that new bone grafts were successfully restored 16 weeks after implantation. Conclusions： This study suggests the feasibility of using porous coral as scaffold material transplanted with marrow derived osteoblasts by TE method. By means of titanium reticulum reinforcement, mandibular defect could be successfully restored. It shows the potentiality of using this method for the reconstruction of bone defect in cfinic.