Angiogenic response induced by acellular brain scaffolds grafted onto the chick embryo chorioallantoic membrane

The repair and regeneration of injured tissues and organs depend on the re-establishment of the blood flow needed for cellular infiltration and metabolic support. Among the various materials used in tissue reconstruction, acellular scaffolds have recently been utilized. In this study, we investigated the angiogenic response induced by acellular brain scaffolds implanted in vivo onto the chick embryo chorioallantoic membrane (CAM), a useful model for such investigations. The results show that acellular brain scaffolds are able to induce a strong angiogenic response, comparable to that of fibroblast growth factor-2 (FGF-2), a well known angiogenic cytokine. The response may be considered dependent on a direct angiogenic effect exerted by the scaffold, because no inflammatory infiltrate was detectable in CAM's mesenchyme beneath the implant. Acellular brain scaffolds might induce the release of endogenous angiogenic factors, such as FGF-2 and vascular endothelial growth factor (VEGF) released from the extracellular matrix of the developing CAM. In addition, the angiogenic response may depend, in part, also on the presence in the acellular matrix of transforming growth factor beta 1 (TGFbeta1).     

聚乳酸-聚羟基乙酸套管复合不同材料修复周围神经缺损的比较研究

目的：研究聚乳酸-聚羟基乙酸（PLGA）套管复合不同材料修复周围神经缺损的能力,筛选周围神经组织工程的支架材料。方法：分别用装配有聚乳酸-聚羟基乙酸（PLGA）丝和人发角蛋白（HHK）的复合导管桥接大鼠10mm长的坐骨神经缺损,术后3、6、9、12周取材,做组织学检查及计量学分析。结果：两种材料均可以诱导神经再生,雪旺细胞和再生神经纤维沿套管的内外表面和桥接材料间隙迁移长入;3周时两种材料已经开始降解,9周时PLGA丝大部分降解,12周时完全降解,HHK降解速度慢于PLGA丝,6周时材料中段切片免疫组化染色显示PLGA丝组在雪旺细胞数量、神经纤维面积上都高于HHK组,有显著性差异。结论：两种材料均有诱导神经再生的作用,PLGA丝组效果更好;桥接丝外面的桥接套管是否有必要保留仍值得进一步的研究和探讨。     

生物衍生骨复合成骨细胞体内异位成骨研究

目的探讨生物衍生骨支架材料复合成骨细胞体内植入的成骨作用,了解其用于骨组织工程支架材料的可行性.方法将经物理、化学方法处理制得的复合型完全脱蛋白骨(CFDB)、部分脱蛋白骨(PDPB)、部分脱钙骨(PDCB)3种生物衍生骨支架材料分别与人胚骨膜成骨细胞体外复合培养1周后,植入裸鼠背部肌肉内作为实验组(30只),以单纯材料植入为对照组(30只),经大体观察、碱性磷酸酶活性测定、常规组织学检查及植入物成骨的定量判断,观测细胞-材料复合物的成骨作用.结果组织学检查证明,实验组3种材料皆有成骨作用,并随植入时间的延长,新骨形成增多;成骨含量分析表明,术后4周和8周,CFDB组组织学评分分别为2.90±0.57和4.60±0.70,显著优于其他实验组.对照组无成骨现象.结论生物衍生骨支架材料可作为骨组织工程支架材料,成骨能力以CFDB为最好.     

Towards a methodology for the effective surface modification of porous polymer scaffolds

A novel low-pressure radio-frequency plasma treatment protocol was developed to achieve the effective through-thickness surface modification of large porous poly (d,l-lactide) (PDLLA) polymer scaffolds using air or water: ammonia plasma treatments. Polymer films were modified as controls. Scanning electron micrographs and maximum bubble point measurements demonstrated that the PDLLA foams have the high porosity, void fraction and interconnected pores required for use as tissue engineering scaffolds. The polymer surface of the virgin polymer does contain acidic functional groups but is hydrophobic.

Following exposure to air or water: ammonia plasma, an increased number of polar functional groups and improved wetting behaviour, i.e. hydrophilicity, of wet surfaces was detected. The number of polar surface functional groups increased (hence the decrease in water contact angles) with increasing exposure time to plasma. The change in surface composition and wettablility of wet polymer constructs was characterised by zeta potential and contact angle measurements. The hydrophobic recovery of the treated PDLLA polymer surfaces was also studied. Storage of the treated polymer constructs in ambient air caused an appreciable hydrophobic recovery, whereas in water only partial hydrophobic recovery occurred. However, in both cases the initial surface characteristics decay as function of time.     

Bioreabsorbable polymer scaffold as temporary meniscal prosthesis

Menisci have an important role in load bearing, shock absorption, knee joint stability, and joint lubrication. Meniscal lesions and meniscectomy are followed by osteoarthritis in a high percentage of patients. At present, there is no ideal prosthesis for meniscal substitution. In this work, a bioreabsorbable polymer scaffold made of poly(L-lactic acid) (PLLA) and poly(p-dioxanone) (PPD) blend was developed to be used as a temporary meniscal prosthesis to stimulate the formation of an in situ meniscal replication while the scaffold is reabsorbed by the organism. Total meniscectomy of medial meniscus and arthrotomy was made in both back knees of 34 adult New Zealand white rabbits by medial parapatellar incision. The scaffolds were sutured in one of the knees, and other was used as a control. A meniscal replica was developed, suggesting that this material has great potential to be used as a meniscal prosthesis, especially because the new meniscus promoted a significant protection of cartilage, and cartilage degeneration in the control condyles was observed.     

Study on biocompatibility of complexes of collagen-chitosan-sodium hyaluronate and cornea

In this study we investigated the biocompatibility of collagen-chitosan-sodium hyaluronate (Col-Chi-NaHA) complexes and cornea tissue, and the feasibility of Col-Chi-NaHA complexes as substrates for cultivating rabbit corneal cells. Different components of Col-Chi-NaHA complexes were prepared and tested. A circular complex film with a diameter of 6 mm was inserted into rabbit stomal pocket and traced for a period of 5 months. Clinical examination was made. Rabbit limbal corneal epithelial cells, corneal endothelial cells, and keratocytes were cultured primarily on complexes. Phase contrast microscope examination was made daily. Histological, immunohistochemical, and scanning electron microscopic examinations were carried out. The complexes of 20% collagen, 10% chitosan, and 0.5% sodium hyaluronate showed rather weak corneal edema and other responses. The degradation of materials was obvious after 5 months. Corneas were transparent and translucent. Cells seeded on Col-Chi-NaHA were allowed to proliferate and partly form confluent monolayer after 9 days in culture. Cultured cells were well attached to the complexes of 20% collagen, 10% chitosan, and 0.5% sodium hyaluronate, or 10% chitosan and 0.5% sodium hyaluronate. The results showed that Col-Chi-NaHA complexes had good biocompatibility with cornea. The complexes can degrade and be absorbed in cornea. Col-Chi-NaHA complex may be a suitable substrate for cultivating corneal cells and a feasible material as a scaffold of tissue-engineered cornea.     

The effect of two different bioreactors on the neocartilage formation in type II collagen modified polyester scaffolds seeded with chondrocytes

The effect of dynamic culture conditions on neocartilage formation in type II collagen modified polyester scaffolds was studied. Porcine or human articular chondrocytes were seeded in the scaffolds. The cell-scaffold constructs were cultivated statically, in a rotating-type bioreactor or in a shaker for up to 4 weeks. The cell proliferation, morphology, NO production, synthesis of proteoglycans and collagen, and mechanical properties were evaluated. The results demonstrated that the rotating-type bioreactor promoted the growth of primary porcine chondrocytes, helped to maintain their phenotype, and increased the production of extracellular matrix. The constructs also had the largest dynamic compressive modulus. In the static condition, chondrocytes occupied only the outer margin of the cell-polymer constructs. The poor mass transfer in static condition may have caused a lower pH value in the middle of the constructs and lead further to faster scaffold degradation as well as the weakest neocartilage. Constructs in the shaker produced the highest amount of NO as well as the lowest amount of cells and matrix production. Human or porcine chondrocytes of the second passage seeded in scaffolds were much less viable, with the largest amount of cells and matrix when cultured in rotating-type bioreactors. A larger seeding density was required to form neocartilage from passaged adult chondrocytes.     

组织工程与人体器官快速成形制造

目的：探讨作为异物植入的修复假体的组织工程化替代物的制造方法。方法：采用快速成形制造技术,利用组织工程材料诱导制造人体器官。结果：实验表明,采用快速成形方法将具有生物学功能的组织工程材料制成支架,较之传统的樾入替代物,具有更好的修复,重建效果。结论：应用组织工程诱导制造的人工器官因能够适时解并最在与新陈代谢而将成为最理想的治疗手段。     

陈旧性腕舟骨骨折三种手术方法的疗效比较

目的:比较三种不同手术方法对腕舟骨骨折的疗效。方法:自1990～1998年,共治疗71例陈旧性腕舟骨骨折,随6访月～4年,平均14个月。随机分成:A组:桡骨茎突切除加带桡动脉茎突返支的桡骨茎突骨瓣组28例;B组:带挠动脉茎突返支的桡骨骨膜组6例;C组:单纯植骨组37例。结果:按刘树清的功能判断标准,优良率:A组为92.85％,B组为82.33％,C组为70.27％。结论:疗效比较,带桡动脉突返支的骨瓣移位效果较其它两组为优。