医用生物材料——骨组织界面研究

已有一系列医用生物材料应用于骨科临床治疗和基础研究体系，材料的生物相容性和物理相容性是应用的最关键内容，而材料－骨组织界面这一相互作用最活跃的部位最能体现二者的程度。本文就界面研究的方法学、影响因素及应用指导意义作一综述。     

磷酸钙的固有骨诱导性及其应用

BACKGROUND: With good biocompatibility, osteoconduction and biodegradability, calcium phosphate ceramics is considered as a substitute of autologous bone; furthermore, it also has the potentiel of osteoinduction after structure optimization.     

骨移植材料及其传导机理

骨移植材料起到了骨传导的作用。骨传导作用与三维材料的结构、化学特性有关。多孔珊瑚陶瓷、羟基磷灰石颗粒、羟基磷灰石－胶原复合物以及金属和生物可降解聚合物都具有骨传导特性。同时模仿骨的结构和组成设计骨移植材料,可得到最佳的传导特性。钙盐和胶原的引入能增强新骨在移植材料中的形成。     

异种煅烧骨材料的研究进展

煅烧骨是一种以羟基磷灰石为主要成分，拥有天然骨结构和形态的生物材料。它所具有的天然的多孔结构以及孔隙大小适合肉芽组织长入和骨、软骨组织的分化形成，并可被机体吸收降解，是一种理想的骨缺损修复材料。本就近年来有关煅烧骨的理化性质，生物相容性，以及煅烧骨同锌离子、成骨细胞、BMP等的复合材料的基础研究进行了综述。     

聚乳酸及其复合材料的性能研究

作者以ZnO为催化剂研制了聚乳酸,测定聚乳酸的力学性能和在磷酸盐缓冲液中的降解性能,以及聚乳酸和羟基磷灰石复合材料的力学性能。了解其用作医用内固定材料和“人工骨”的可行性。     

多孔材料应用在组织工程中的现状及前景CSCD

背景:近年来多孔材料体内植入的基础研究和临床应用均展示了良好的应用前景。目的:回顾近10年来组织工程多孔材料的基础与临床研究进展,总结存在的问题并展望未来。方法:由作者检索PubMed数据库和中国知网数据库获得文献,英文检索词为porous material,bone implantation",中文检索词为"多孔材料,骨移植"。纳入用于体内外及临床研究的多孔材料及其复合材料,以及与骨缺损修复或骨组织工程密切相关的多孔材料。结果与结论:目前研究较多的多孔材料有羟基磷灰石、钛及其合金、聚乙烯、磷酸钙类等,从大量的体内外实验结果来看,多孔材料展示了其良好的组织相容性和骨诱导特性,但有利于组织最快和最有效长入的孔隙尺寸尚无统一的标准,不规则异形多孔材料的孔隙率怎样获得和控制,材料的弹性模量如何调控,以及如何获得材料100%的有效孔隙率等问题尚未有明确的标准答案,另外临床应用过程中发生的炎症和暴露等并发症的问题是否与前述问题相关还无法确定。     

复合富血小板血浆珊瑚骨修复下颌骨缺损

BACKGROUND: Platelet rich plasma contains various growth factors, such as platelet-derived growth factor, metastatic growth factor, insulin-like growth factor, epidermal growth factor as well as vascular endothelial growth factor. Therefore, it can directly or indirectly promote cell differentiation and proliferation in different stages of bone regeneration.     

微晶玻璃人工骨材料的研究

本文描述了一种新型微晶玻璃人工骨材料的制备方法。一系列的试验表明新材料具有良好的力学性能及生物活性。采用扫描电镜及电子探针等分析技术研究了材料与骨结合界面的结构。新材料适合作为各种复杂形状的人工骨材料。     

骨修复材料的研究进展

由于自体骨和异体骨移植治疗骨缺损存在许多不可避免的问题,所以,人们开始研制人工骨修复材料。本文综述了生物陶瓷、胶原、脱钙骨、合成聚合物等骨修复材料的研究和应用现状。作者认为,将几类生物材料复合加工,研制出类似于人体骨组织的材料,将是今后骨修复瓣发展趋。     

成骨诱导脂肪基质细胞在骨组织工程体内成骨中的作用

背景：以往研究认为,经过成骨诱导后的脂肪基质细胞通过转化为成骨细胞分泌骨基质进而修复骨缺损,然而并没有明确结论证实。 目的：将经过体外成骨诱导的脂肪基质细胞复合支架材料分别植入骨缺损区和非骨区,根据是否成骨,验证经过成骨诱导后的脂肪基质细胞是否转化为成骨细胞。 方法：取12月龄犬背部皮下脂肪,经胶原酶消化法获得单个核细胞,将培养的第3代细胞与双相磷酸钙陶瓷形成复合物。在犬下颌骨两侧制备长20 mm、高10 mm的箱状缺损,拔除术区牙齿,将细胞支架复合物植入一侧术区,空白侧留作对照;另外在犬背部皮下肌肉区植入细胞支架复合物及骨诱导性磷酸钙陶瓷材料,术后6周及12周经组织学检测骨缺损修复情况。 结果与结论：脂肪基质细胞复合双相磷酸钙陶瓷在骨缺损区成骨,在肌肉区未形成新骨;骨诱导性磷酸钙陶瓷在肌肉区形成新骨。提示成骨诱导并不能将脂肪基质细胞转化为成骨细胞,其确切机制有待进一步研究。     

晶须化磷酸钙多孔生物活性陶瓷修复犬股骨髁缺损

BACKGROUND: Previous studies have demonstrated that the internal microstructure of porous calcium phosphate ceramics after the whiskering process has some changes, and obtain good mechanical properties. OBJECTIVE: To further investigate the effect of whisker-covered porous calcium phosphate ceramics in repair of canine femoral condyle defects. METHODS: Highly interconnected porous calcium phosphate ceramics was prepared by placeholder method. The whiskering of the materials was finished by hydrothermal process. Fifteen healthy adult beagle dogs were selected in this study. A 10 mm×10 mm cylindrical inclusive bone defect was made bilaterally on the lateral femoral condyle with a drill. The porous calcium phosphate ceramics after the whiskering process was implanted onto the right femoral condyle as experiment group. The porous calcium phosphate ceramics without the whiskering process was implanted onto the left femoral condyle as control group. At 2, 4, 8, and 12 weeks after implantation, X-ray and dual-energy X-ray test were conducted in the bone defect area respectively. RESULTS AND CONCLUSION: (1) X-ray: With the increase of time, the interface between bone defect and normal bone of two groups gradually blurred, disappeared, and completely fused at 12 weeks. The material in the control group was partially dissolved, while there was no obvious dissolution in the experiment group. No significant difference in the X-ray scores was found between two groups at different time points. (2) Dual-energy X-ray: With the increase of time, the bone mineral density of the two groups both increased gradually, but there was no significant difference in the bone mineral density at different time points between these two groups. These results demonstrate that the porous calcium phosphate ceramics after the whiskering process has good ability to repair the defects of femoral condyle.       

川续断复合磷酸钙骨修复骨缺损

背景：复合磷酸钙骨植入材料的物理结构和无机成分与人体骨相似,具有良好的生物可吸收性和生物相容性。研究证实续断细粉能明显提高骨缺损修复速度。 目的：观察川续断复合磷酸钙骨复合植入材料修复骨缺损的效果。 方法：在新西兰大白兔双侧下颌骨体部制备长约1.0 cm、宽约0.5 cm、深约0.3 cm的骨缺损,右侧植入川续断复合磷酸钙材料作为实验组,左侧植入磷酸钙骨材料作为对照组。植入后4,8,12周取材,进行大体观察、CBCT检测、扫描电镜、组织学观察。 结果与结论：①大体观察：实验组成骨速度、材料降解率及硬度高于对照组。②CBCT检测：实验组材料与周围组织结合紧密度强于对照组,且材料降解速度快于对照组。③扫描电镜：两组材料与周围正常骨组织间大多由纤维结缔组织充盈,实验组比对照组更为紧密,空隙更加微小,随着时间的增加,材料与周围正常骨组织的结合更为紧密。④组织学观察：实验组成骨速度及成骨活性优于对照组。表明川续断复合磷酸钙骨植入材料具有明显加速成骨的作用。     

A preliminary study on osteoinduction of two kinds of calcium phosphate ceramics.

With respect to the effect of material factors on calcium phosphate biomaterial-induced osteogenesis, the osteoinductive property of two kinds of porous hydroxyapatite ceramics, which were made by different producers, was investigated in dorsal muscles of dogs. One hydroxyapatite ceramic (S-HA), macroporous implants with rough pore walls containing abundant micropores, was made by Sichuan Union University (Chengdu, China); the other hydroxyapatite ceramic (J-HA), porous implants with smooth macropore walls composed of regularly aligned crystal grains, was provided by Mitsubishi Ceramic Int. (Japan). Different tissue response was detected histologically and microradiographically after the ceramic samples had been implanted in dorsal muscles of dogs for 3 and 6 months. Bone formation was found in S-HA at 3 months, which increased at 6 months. In contrast, no bone formation was detected in J-HA at both 3 and 6 months. These results indicate that with the special architecture, calcium phosphate ceramic can induce bone formation in soft tissue. As both materials were very similar in their chemical and crystallographic structures, but varied in their microstructures, the latter seem to be an important factor affecting the osteoinductive capacity of calcium phosphate ceramics. These data suggest that, by controlling the preparation of calcium phosphate ceramic, bone substitutes with intrinsic osteoinductive property can be developed from calcium phosphates.     

In vivo evaluation of a porous hydroxyapatite/poly-DL-lactide composite for bone tissue engineering

As reported previously, a porous composite of uncalcined hydroxyapatite (u-HA) and poly-DL-lactide (PDLLA) showed excellent osteoconductivity and biodegradability as a bone substitute in rabbit model. In this study, to investigate the usefulness of this composite as a scaffold loaded with cells, we estimated whether this material showed osteogenesis on implantation to extraosseous site. On loading with syngeneic bone marrow cells and implantation into rat dorsal subcutaneous tissue, osteogenesis with enchondral ossification was seen both on and in the material at 3 weeks after implantation. The osteogenesis in the u-HA/PDLLA had progressed, and newly formed bone tissue was found in the material by 6 weeks. To investigate the osteoinductive properties of the material, we implanted this porous composite material into extraosseous canine dorsal muscle. At 8 weeks, osteogenesis was seen in the pores of the material. Newly formed bone could be observed adjacent to the material. In addition, cuboidal osteoblasts adjacent to the newly formed bone were evident. Neither cartilage nor chondrocytes were found. These results might indicate that the material induced osteogenesis by intramembranous ossification. Conversely, similar porous PDLLA did not induce osteogenesis during the observation period. Therefore, porous HA/PDLLA, which has osteoconductive and osteoinductive properties, might be a useful material for use as a bone substitute and cellular scaffold.     

纳米羟基磷灰石复合基因转染生长因子修复牙槽骨缺损

背景：研究发现成骨细胞可促进牙槽骨的形成,而血小板衍生生长因子A因子转染成骨细胞对于牙槽骨形成的作用尚不清楚。 目的：将基因转染的血小板衍生生长因子A重组质粒与纳米羟基磷灰石复合移植到骨缺损处,观察其对骨缺损修复的影响。 方法：将24只新西兰大白兔随机分成实验组与对照组,制作双侧下颌下缘10 mm×6 mm×4 mm骨质缺损,实验组植入血小板衍生生长因子A转染成骨细胞与纳米羟基磷灰石的复合材料,对照组单纯植入纳米羟基磷灰石。术后4,8,12周取材行大体标本、锥形束CT、组织学观察及扫描电镜观察。 结果与结论：术后不同时间点,实验组缺损处新骨生成,成骨细胞、骨小梁、骨陷窝及新生血管修复情况,以及材料与牙槽骨连接处的骨结合均明显优于对照组(P < 0.05)。表明血小板衍生生长因子A转染成骨细胞与纳米羟基磷灰石复合生成的新型材料,有较好的生物相容性,可加速骨组织再生,促进骨组织缺损修复。     

Evaluation of the expression of collagen type I in porous calcium phosphate ceramics implanted in an extra-osseous site

The aim of the present study is to demonstrate the newly formed tissue in calcium phosphate (Ca/P) ceramics after extra-osseous implantation by histological and immunohistochemistry (IHC) methods. Synthesis porous Ca/P ceramics without adding any growth factor and living cell were implanted in the dorsal muscle of dogs for 1 and 2 months. Undecalcified and decalcified sections were stained by hematoxylin and eosin (H&E), and IHC, respectively. The histological results showed the beginning of osteogenesis and angiogenesis after being implanted for 1 month and the obvious new bone formation after being implanted for 2 months. IHC were conducted via the avidin-biotin peroxidase complex (ABC) method and the primary antibody was collagen type I. IHC results indicated that collagen type I was expressed within osteoblast-like cells and newly formed bone-like tissue in Ca/P ceramics after 1 month, and in the mineralized matrix of newly formed bone and osteoblasts, some osteocytes and some lacunae after 2 months. No cartilage and chondrocytes were observed in the histological and IHC-stained sections. Evidence of intramembranous osteogenesis was confirmed.     

Bioactivity and osseointegration study of calcium phosphate ceramic of different chemical composition

Synthetic hydroxyapatite (HA) and tricalcium phosphate (TCP) are promising bone-substitute materials in the orthopaedic and dental fields, as their chemical composition is similar to that of bone. This study investigated the osseointegration performance of carbonated biphasic calcium phosphate (CBCP) ceramics containing carbonated hydroxyapatite and tricalcium phosphate prepared by microwave irradiation, in femoral defects of dogs. The defects were created as 3-mm holes on the lateral aspect of femur and filled with the implant material. The serum was collected postoperatively and biochemical assays for alkaline phosphatase activity levels were carried out. The animals' defective sites were radiographed at 4, 8, and 12 weeks. The radiographic results showed that the process of ossification started after 4 weeks and the defect was completely filled with new bone after 8 weeks. Histological examination of the tissue showed the osteoblastic activity inducing the osteogenesis in the defect. The complete haversian system with osteoblastic and osteoclastic activity and bone remodelling process were observed after 12 weeks. The alkaline phosphatase activity levels also correlated with the formation of osteoblast cells. This calcium phosphate ceramic has proved to work well as a biocompatible implant and as an osteoconductive and osteoinductive material for the filling of bone defects.     

Ceramic drug delivery: a perspective

Different ceramic substances are offered in the market as bone substitute materials. These include monophasic calcium phosphate ceramics of tricalciumphosphate (TCP) or hydroxyapatite (HA), biphasic calcium phosphate ceramics and multiphasic bio-glasses synthetic calcium phosphate cements. Ceramics with appropriate three-dimensional geometry are able to bind and concentrate bone morphogenetic proteins in circulation and may become osteoinductive (capable of osteogenesis) and can be effective carriers of bioactive peptide or bone cell seeds and are therefore potentially useful in tissue engineering and drug delivery. An attempt has been made to review various drug delivery applications of ceramics.     

The influence of genetic factors on the osteoinductive potential of calcium phosphate ceramics in mice

The efficacy of calcium phosphate (CaP) ceramics in healing large bone defects is, in general, not as high as that of autologous bone grafting. Recently, we reported that CaP ceramics with osteoinductive properties were as efficient in healing an ilium defect of a sheep as autologous bone graft was, which makes this subclass of CaP ceramics a powerful alternative for bone regeneration. Although osteoinduction by CaP ceramics has been shown in several large animal models it is sporadically reported in mice. Because the lack of a robust mouse model has delayed understanding of the mechanism, we screened mice from 11 different inbred mouse strains for their responsiveness to subcutaneous implantation of osteoinductive tricalcium phosphate (TCP). In only two strains (FVB and 129S2) the ceramic induced bone formation, and in particularly, in FVB mice, bone was found in all the tested mice. We also demonstrated that other CaP ceramics induced bone formation at the same magnitude as that observed in other animal models. Furthermore, VEGF did not significantly increase TCP induced bone formation. The mouse model here described can accelerate research of osteoinductive mechanisms triggered by CaP ceramics and potentially the development of therapies for bone regeneration.