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As the human population ages and the life expectancy increases,tendon injuries will become more prevalent,especially among young individuals.Though the traditional operative therapy for tendon lesion can relieve the suffering of patients,the functional reconstruction is usually not optimistic.Tissue engineering is an advancing field,as the technology of construction in vitro and application in vivo matures,that can provide a more promising approach for tendon repair without tendon autograft.Challenges and future directions in the field of tendon tissue engineering focusing on four key parameters:seed cells,novel scaffolds,and mechanical stimulation.Recently,the discovery of TDSCs (tendon-derived stem cells) provides new ideas for the selection of seed cells and effect of mechanical stimulation on the tendon tissue engineering has become a hot spot.This article provides a review of recent progress in research about seed cells,scaffolds and mechanical stimulation for tendon engineering,and also speculates on the development in the future.
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Objective To investigate the tissue remodeling and cell alignment of TDBM scaffolds seeded with rabbit tenocytes under the cycle dynamic tensile force or static tension-free culture in vitro. Methods TDBM were made by ourselves, and uniaxial cyclic tendon stretching device was designed and manufactured on our own. Primary tenocytes were isolated from the Achilles tendon of three-day-old New Zealand white rabbits and seeded into scaffolds, and were cultured collectively in DMEM in vitro. Samples were divided into two groups:dynamic tension-loaded group, and static tension-free group. Fresh natural tendons were used to be positive control. The experiment's time was six weeks. The scaffold-cell complexes were harvested at 3 and 7 days of culture for Inverted microscope and scanning electron micrograph (SEM) analysis. The morphological characters of the samples, including the general view, HE and Masson's dyeing, were observed at 2, 4 and 6 weeks. In addition, the gene expression of the I-type collagen and III-type collagen of the samples was detected by using Real time PCR at every week. Set fresh natural tendon as control. Results The inverted microscope and SEM showed that it was nice compatible condition between the tendon cells and TD-BM scaffold. In addition, the tendon of tension-loaded group revealed a structure of longitudinally aligned collagen fi bers and dense structure of collagen fibers arranged in orderly form a unique corrugated structure. Tenocytes layer located between the col-lagen fibers and aligned longitudinally along the force axis, with increased matrix deposition after the 3th week showed by RT-PCR. The cell/matrix ratio decreases. When cultured to 6 weeks, the tissue structure was very similar to that of fresh natural ten-don pattern. By contrast, HE and Masson's staining revealed the collagen fibro-tissue structure in tension-free groups with disorga-nized matrix structure and randomly distributed cells. Collagen fibers were gradually degraded with time. In tension-loaded group, Real-time PCR showed that gene expression of I-type collagen and III-type collagen gradually increase, but in tension-free group, the relative gene expression of I-type collagen and III-type collagen was highest at 3rd week, and from that time the relative expres-sion gradually decrease. Conclusion Under the dynamic stress, the TDBM scaffolds seeded with rabbit tenocytes can promote extra-cellular matrix biosynthesis and tendon structure remodeling, which is a promising method for tendon tissue engineering.
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The importance of cultivating evidence-based consciousness of thinking and implementation capability of specialization postgraduates was analyzed,and experiences and suggestions acquired from the practice of teaching of specialization postgraduates were shared by demonstrating the enlightening of evidence-based consciousness of thinking,the cultivation of evidence-based implementation capability and the establishment of evaluation system,with PBL integrated.
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[Objective]To study the stability function of Luschka Joint(LJ) of lower cervical spine.[Method]C_(3、4) and C_(5、6) as a funtional spinal unit(FSU) were taken from 16 fresh adult cadavers and randomly divided into experimental group,its LJ was cut out and in control group,LJ was maintained.The FSU of C_(3、4) and C_(5、6)was loaded and tested on the AG-10 AT automatic electronic versatile machine in normal,flexion ≤10? and extension ≤7.5? positions.Data of sigattal horizontal displacement(SHD),rotational angulation(RA) and coronary laterral displacement(CLD) were collected,counted and 3-dimesionally analyzed by computer.[Result]The SHD,RA and CLD of FSU experimental group were significantly different with that of control group(P
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0.05),which hint that the MSCs function was induced to cartilage in collagen synthesis,but MSCs collagen function level was lower than that of cartilage.[Conclusion]MSCs can be induced to cartilage-collagen function cell in low centrifuge stress combined with TGF-?.GDABM show good biocompatibility combined with MSCs and can provide a promising extracellular matrix scaffold for cell transplantation in cartilage tissue engineering.
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0.05),hints that the tenocyte's function was not disturbed. The DNA index of cells of GDBM group was 0.96 and 2.1% higher than the control group,indicating that the tenocytes grow and proliferate faster when being combine cultured on GDBM. Conclusion GDBM show good biocompatibility combined with tenocytes and they are promising extracellular matrix scaffold for cell transplantation in tendon tissue engineering.
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0.05), hinted that the tenocyte's function was not disturbed. The DNA index of cells of TDBM group was 0.96, 10.1% higher than the control group, indicating that the tenocytes grow and proliferate faster when being combine cultured on TDBM. Non malproliferation of tenocytes were founded, and lots of collagen formed among TDBM fibers within 2 months in vitro culture. Conclusion TDBM show good biocompatibility combined with tenocytes because of more similarity of surface and component with tendon. It could be promising extracellular matrix scaffold for cell transplantation in tendon tissue engineering.