复合型纳米羟基磷灰石人工骨研究进展

羟基磷灰石人工骨具有良好的生物相容性和生物活性,其缺点是脆性较大及骨诱导性较弱.与纳米羟基磷灰石复合的有机高分子材料具有生物相容性和可降解性,复合后能相互补强,从而可提高人工骨的强度和韧性,有效修复骨缺损;纳米羟基磷灰石和天然高分子材料复合后可达到松质骨的强度;骨生长因子加入复合人工骨,缓释后持续诱导骨生成,使复合人工骨获得骨诱导性能;纳米双相生物陶瓷的降解性能较纳米羟基磷灰石好,多孔隙纳米双相陶瓷人工骨有骨传导性和成骨性.理想的人工骨不是拘泥于对骨组织结构和成分的简单模仿,而是要构建符合生物学特性的多孔隙、高强度骨细胞爬行支架.     

复合珊瑚羟基磷灰石人工骨的研制及其成骨效应

目的 自行研制复合珊瑚羟基磷灰石人工骨并评估其成骨效应。方法 取南海澄黄滨珊瑚碳酸钙在特定条件下经过“热液交换反应”，制成单纯珊瑚羟基磷灰石(coralline Hydroxyapatite，CHA)人工骨，并将其与基因重组骨形态发生蛋白(rhBMP2)和几丁糖复合制成了三种复合珊瑚羟基磷灰石(composite Coralline Hydroxyapatite，CCHA)人工骨，将此三种不同配型的复合人工骨和单纯CHA人工骨分别植入四组24只SD大白鼠肌肉内。手术后2、4、6、8周取材进行组织学观察，计数高倍单位视野内的成骨细胞数量和炎性细胞数量。采用SPSS8.0统计软件处理系统分析。结果 术后各时期取材结果显示：B组(CHA rhBMP2)和D组(CHA rhBM2P 几丁糖)的单位视野内成骨细胞数量明显多于A组(单纯CHA)和C组(CHA 几丁糖)：而C组和D组的单位视野内炎性细胞数量明显少于A组和B组。即D组人工骨的单位视野内的成骨细胞数量多、炎性细胞少。结论 rhBMP2-几丁糖／CHA复合人工骨不但具有显著的成骨诱导作用，还具有炎症反应轻及持续的诱导成骨作用，是一良好的骨移植替代物。     

壳聚糖/羟基磷灰石支架修复骨软骨缺损的实验研究

[目的] 探讨双层壳聚糖(chitosan CS)/羟基磷灰石复合支架(hydroxyapatite HA)修复兔骨软骨缺损的可行性.[方法] 采用冻干法和烧结法制作双层壳聚糖(CS)/羟基磷灰石(HA)复合支架,以骨髓间充质干细胞为种子细胞,运用纤维蛋白胶种植技术,以双层壳聚糖(CS)/羟基磷灰石(HA)复合支架为载体,修复骨软骨缺损,实验分3组,A组:BMSc 支架,B组:单纯支架,C组:未处理.将修复材料植入骨软骨缺损模型,分别于6、12周取材,进行大体观察,组织学检测,改良Wakitani法评分,经统计学处理,比较各组修复效果差异(P＜0.05).[结果] (1)CS/HA支架CS层孔隙率为76%± 5.01%,孔径为200～400 μm,平均为300 μm左右,孔相通性好,HA层孔隙率为72%± 4.23%,孔径为200～500 μm,平均为350 μm左右,孔相通性好,结合部结合好;(2)P2骨髓间充质干细胞较纯,扫描电镜观察MSCs附着在复合支架上.大体观察和组织学检测显示, A组基本修复软骨缺损,骨缺损有骨小梁长入.B、C组骨软骨缺损修复不良,组织学检测以纤维性组织或无新生组织形成,软骨及骨缺损均明显存在,改良Wakitani评分显示A组在6周、12周2个时间点的各项评分结果,均优于B、C组,且差异有统计学意义(P＜0.05).[结论] 双层壳聚糖(CS)/羟基磷灰石(HA)复合支架可作为骨软骨组织工程支架,结合BMSc可修复软骨与骨的缺损,重建关节的解剖结构和功能.     

纳米羟基磷灰石骨修复材料研究进展

纳米羟基磷灰石(HAP)骨修复材料具有良好的生物学特性和生物相容性,与胶原、骨形态发生蛋白、血管内皮生长因子、壳聚糖、蚕丝蛋白、半水硫酸钙等复合后的理化性质得到明显改进,载入抗生素后成为一种有效的载药系统,其生物安全性评价有待进一步深入。该文就纳米HAP及其与天然材料、非天然材料复合后的理化性质,载入抗生素后的特点作一综述。     

骨髓间充质干细胞转染HIF-1α复合纳米人工骨对兔桡骨骨缺损的修复作用

目的：以骨髓间充质干细胞（bone marrow mesenchymal stem cells, BMSCs）为种子细胞,将携带低氧诱导因子-1α（hypoxia-inducible factor-1α, HIF-1α）的慢病毒感染BMSCs后与纳米羟基磷灰石人工骨（Nano-hydroxyapatite, Nano-HA）复合,填充植入兔桡骨缺损部位,探讨HIF-1α对骨缺损的修复作用。方法：将构建的重组HIF-1α慢病毒质粒转染293Ta细胞。取兔胫骨的骨髓,使用全骨髓贴壁筛选法分离培养BMSCs,通过形态观察及流式细胞仪检测细胞。将携带HIF-1α慢病毒感染BMSCs。将感染携带HIF-1α慢病毒后的BMSCs与Nano-HA共培养得到HIF-1α-eGFP/BMSCs/Nano-HA人工骨材料,将体外复合培养后的人工骨材料填充植入兔桡骨骨缺损部位,使用新西兰大白兔30只,随机分为3组,每组10只。实验后12周分别检测兔桡骨大体标本、X光、病理切片,分析比较桡骨缺损的愈合情况。结果：1、将携带HIF-1α慢病毒质粒转染293Ta细胞48小时,收取病毒,计算得出病毒滴度为5.0×107TU/ml。流式细胞仪对细胞表面标记物CD90、CD105和CD34、CD45检测,CD90、CD105阳性率为99.3%,CD34、CD45为阴性。2、动物实验：在术后12周对各组大体标本、X线、组织切片进行检测,发现A组HIF-1α-eGFP/BMSCs/Nano-HA复合人工骨、B组BMSCs/Nano-HA复合人工骨均可促进骨缺损修复,而A组HIF-1α-eGFP/BMSCs/ Nano-HA复合人工骨的新骨形成量更大,骨缺损修复能力优于B组。C组骨缺损区无骨性连接,骨缺损未能修复。结论：BMSCs作为骨组织工程种子细胞参与成骨,HIF-1α基因促进BMSCs诱导成骨、成血管,增强新生骨组织的形成,更有效地修复骨缺损,Nano-HA具有良好的骨传导性,HIF-1α-eGFP/BMSCs/Nano-HA复合人工骨具有良好的骨缺损修复能力,具备成为一种理想骨缺损修复材料的可能。     

碳纳米管/羟基磷灰石/壳聚糖骨修复材料的制备及细胞相容性研究

目的 设计一种多壁碳纳米管/纳米羟基磷灰石/壳聚糖(MWCNT/n-HA/CS)复合材料的骨组织工程支架,并对这种支架进行理化性质检测及细胞相容性评价。 方法 采用溶液共混、冷冻干燥法制备MWCNT/n-HA/CS支架。通过扫描电镜、X线衍射和傅立叶红外光谱分析其微观形貌和组成;采用陶瓷试验系统进行支架的机械性能检测,并评价MWCNT的加入对支架的影响。使用第3代兔骨髓间充质干细胞( BMSCs),使用扫描电镜检测支架对其粘附作用,采用MTT法检测细胞在支架上增殖,并评价碳纳米管的加入对支架的细胞相容性影响。评估设计的支架是否可用于骨组织工程。 结果 MWCNT/n-HA/CS支架具有明确的多孔结构,孔隙率高(87.26％),碳纳米管的加入可明显提高断裂强度（提高66％）,而对孔隙率无明显影响（下降3％）,对HA、CS的理化性质无明显影响。BMSCs在支架上粘附、增殖正常,且MWCNT具有促进细胞增殖能力。 结论 MWCNT/n-HA/CS支架具有较好的机械性能、合适的孔径大小、良好的细胞相容性,有望用于骨组织工程。     

新型聚乳酸复合纳米羟基磷灰石人工骨的细胞相容性

目的前期试验证实,当纳米羟基磷灰石含量为20%时的聚乳酸复合纳米羟基磷灰石人工骨材料能满足人体骨缺损修复的生物力学要求,尚需进一步的观察其细胞相容性,为临床应用提供参考数据。方法制备纳米羟基磷灰石含量为20%时的聚乳酸复合纳米羟基磷灰石人工骨材料,并提取浸提液。设立阴性对照组(含10%胎牛血清的DMEM完全培养基)、实验组(浸提液)、阳性对照组(质量浓度为0.64%的苯酚),用兔骨髓间充质干细胞与材料浸提液共培养的方式进行。观察兔骨髓间充质干细胞在培养3,5,7 d各时相点的细胞形态学变化,运用MTT比色法,测定上述各组兔骨髓间充质干细胞细胞培养3,5,7 d的相对增殖度,判断材料对细胞的毒性程度。结果随着时间的延长,3组细胞的吸光度值均明显增加(P<0.01)。实验组兔骨髓间充质干细胞相对增殖度在第3,5,7天分别为95.3%,96.8%和97.6%,参照国家标准聚乳酸复合纳米羟基磷灰石人工骨材料的细胞毒性为1级;实验组与阴性对照组比较差异不显著(P>0.05),阳性对照组与其他两组比较差异显著(P<0.05)。实验组细胞形态正常,呈梭形,贴壁生长良好。结论聚乳酸复合纳米羟基磷灰石人工骨材料细胞相容性良好,细胞毒性为1级,参照GB/T16886.5.2003标准属于安全范围。     

珊瑚羟基磷灰石人工骨的研究进展

珊瑚羟基磷灰石人工骨的研究进展尹庆水钟世镇寻求和研制理想的骨移植材料是医学生物材料科学领域的一项重要课题。利用磷酸钙类物质为骨移植物已有近百年历史。近２０年来，化学合成和从牛骨中烧结而成的羟基磷灰石较广泛应用骨移植的实验和临床，取得一定效果。但从牛骨...     

骨形态发生蛋白-2/胶原/掺锶羟基磷灰石材料修复颅骨缺损

目的 制备骨形态发生蛋白-2( BMP-2)/胶原/掺锶羟基磷灰石材料并探讨其修复大鼠颅骨缺损的可行性和有效性.方法 扫描电镜观察Ⅰ型胶原制备单纯胶原、胶原/羟基磷灰石、胶原/掺锶羟基磷灰石、BMP-2/胶原/掺锶羟基磷灰石4组骨修复材料表面结构.用BMP-2/胶原/掺锶羟基磷灰石材料浸提液进行细胞毒性试验和体外溶血试验评价其生物相容性.在大鼠头颅制备颅骨极限骨缺损模型,分别植入4种骨修复材料.术后12周CT扫描观察骨缺损修复影像学.苏木素-伊红(HE)和Masson染色观察骨缺损组织学变化,并在骨缺损及其周围新生骨部位行骨桥蛋白( OPN)和β-连环蛋白(β-catenin)免疫组织化学染色.结果 在扫描电镜下观察发现单纯的胶原材料为交织样物质结构,胶原/羟基磷灰石材料为交织晶体板状结构胶原/掺锶羟基磷灰石和BMP-2/胶原/掺锶羟基磷灰石材料晶体结构为单晶体交织状.BMP-2/胶原/掺锶羟基磷灰石材料浸提液对细胞相对增殖率(RGR)无显著影响(P＞0.05),材料的细胞毒性为1级.骨缺损CT扫描平均CT值分别为(98.5±10.2)、(208.4±19.5)、(418.4±27.1)、(476.8±30.5)hu,BMP-2/胶原/掺锶羟基磷灰石材料缺损部位CT值最高.HE和Masson染色见BMP-2/胶原/掺锶羟基磷灰石组骨质愈合完全,原骨缺损处多为红色成熟骨.胶原/掺锶羟基磷灰石组植入区内蓝色的新生骨较多.胶原/羟基磷灰石材料组,植入区在植入材料边缘新生骨形成,界限仍然清晰.单纯胶原组骨质未愈合,骨缺损处为淡蓝色条索状结构,中间未见骨形成.对比其他3组,BMP-2/胶原/掺锶羟基磷灰石组存在大量棕色的OPN和β-catenin染色阳性新生骨组织,差异有统计学意义(P＜0.05).结论 BMP-2/胶原/掺锶羟基磷灰石材料促进骨修复能力强于单纯胶原、胶原/羟基磷灰石、胶原/掺锶羟基磷灰石材料.     

明胶/纳米羟基磷灰石三维多孔骨支架的制备及其生物安全性评价

[目的]探讨冷冻干燥法制备明胶/纳米羟基磷灰石(nano-hydroxyapatite,nHA)三维多孔支架的可行性并评价材料的生物安全性。[方法]取明胶水溶液,将其分别与10 wt%、20 wt%、30 wt%的nHA混合,交联后采用冷冻干燥法制备明胶/nHA三维多孔支架。评价材料的理化性质,通过测定支架孔径、孔隙率、吸水率、抗压强度及降解pH值优化制备条件;MTT法分析支架浸提液毒性;共培养观察细胞在材料表面及周围生长情况;材料埋入背部肌肉内,组织学染色观察评价其生物安全性。[结果]体视显微镜及电镜显示,制备的支架均呈三维多孔隙结构。随着nHA含量的增加,材料成孔效果变差,孔径、孔隙率、吸水率变小,而抗压强度增加。其中以nHA含量为20 wt%的材料表现更为适宜,并选其进行生物相容性实验。MTT法显示不同浓度支架浸提液与对照DMEM培养液吸光度值比较,差异无统计学意义(P>0.05)。细胞与材料共培养生长状态良好。HE染色观察材料与周围肌肉组织无排斥反应,组织相容性良好。[结论]制备的明胶/nHA支架材料具有三维孔隙结构,具备合适的孔径和孔隙率,无毒,生物相容性良好,可作为骨组织工程支架使用。     

羟基磷灰石-软骨细胞复合物的构建

目的探讨以块状多孔羟基磷灰石（ＨＡ）作为软骨细胞培养的载体,构建一种促进骨愈合的植入材料的可行性。方法采取成年雄性ＳＤ大鼠肋软骨细胞,以３ｍｍ×３ｍｍ×４ｍｍ大小的块状多孔ＨＡ为载体培养软骨细胞;培养３天和７天后通过扫描电镜观察ＨＡ表面和中矢横断面孔隙中有无细胞生长,同时将培养２天的细胞爬片以α１（Ⅱ）ｃＤＮＡ片段为探针进行原位杂交,求证培养的细胞是否软骨细胞。结果细胞爬片原位杂交染色强阳性,证实是软骨细胞,且ＨＡ表面和中矢横断面孔隙内壁上均有细胞生长,随培养时间增加细胞数明显增加。结论ＨＡ可以作为细胞培养的贴壁底物,软骨细胞可以长入多孔ＨＡ内部的孔隙中。     

纳米脱钙骨基质的制备及其性能检测

[目的]通过MICROS超细粉碎机制备同种异体纳米脱钙骨基质(DBM),观察纳米DBM结构特征,研究DBM纳米化工艺及其作为骨移植替代物的生物相容性.[方法]采用改良Urist法制备同种异体脱钙骨基质,液氮冷冻球磨机将块状DBM预粉碎,使用MICROS超细粉碎机进一步研磨粉碎制备纳米DBM.电镜扫描观察其结构,按照我国卫生部<生物材料和医疗器材生物学评价的技术要求>中的标准,对纳米DBM进行急性毒性实验、热原实验、溶血实验等检测.[结果]制备颗粒直径在50～200纳米的脱钙骨基质,生物相容性检测无毒性,无热源性,不引起溶血反应,纳米DBM具有良好的生物相容性.[结论]纳米DBM可在低温或控制温度条件下制备,是一种无毒、无刺激,不含热源、不引起免疫排斥反应的生物材料,具有良好生物相容性.     

Adherence of osteoblast-like cells on calcospherites developed on a biomaterial combining poly(2-hydroxyethyl) methacrylate and alkaline phosphatase.

The polymer poly(2-hydroxyethyl) methacrylate (pHEMA) can copolymerize with alkaline phosphatase (AlkP) to form a hybrid material. The enzyme retains its biological activity and forms hydroxyapatite nodules (calcospherites) when polymer pellets are incubated with a synthetic body fluid. Osteoblast-like cells (ROS 17/2.8) were seeded on pellets of pHEMA and pHEMA-AlkP on which calcospherites were grown. They were examined by scanning electron microscopy (SEM) with backscattered electron imaging. Cell surface and shape were measured by image analysis combining the SEM images. Cells grown on pHEMA-AlkP had an increased surface area (449 +/- 216 microm(2) vs. 204 +/- 80 microm(2)). The number of filopodia anchoring the cells on the free polymer surface was reduced on pHEMA-AlkP, but numerous thick pseudopodia permitted a direct anchorage on the calcospherites. Pseudopodia were wider and longer than the filopodia. The backscattered images revealed that each cell was seated on 7.1 +/- 1.5 calcospherites and partially covered 10.3 +/- 1.9 others. Antifibronectin and anti-bone sialoprotein antibodies were used to investigate cell attachment. With confocal microscopy, both molecules were located at the interface between the cells and the mineral, inside the cells, and as free molecules on the calcospherites. Immunogold labeling was done with the same antibodies and examined with transmission electron microscopy (TEM). Adsorption of fibronectin and bone sialoprotein was noticeable at the cell/calcospherite interface and on the surface of the hydroxyapatite crystals. Immunogold studies revealed adhesion proteins (bone sialoprotein, fibronectin) to be present at the surface of crystals and at focal points of cell contact.     

猪骨膜去细胞支架的制备及其生物相容性

目的探索猪骨膜去细胞支架的制备及检测,并观察其生物相容性。方法从猪扇骨上获得骨膜去细胞支架。通过扫描电镜观察、HE染色、DNA提取测定、Masson染色和羟脯氨酸测定法进行定性定量检测,并与培养至第3代HFLS滑膜成纤维细胞共培养48 h。结果骨膜组织经去细胞处理后,组织表面的连续性并未中断、无残留细胞、胶原成分被保留,具有良好的生物相容性。结论所获取的猪骨膜去细胞支架细胞去除彻底,细胞外基质的结构及主要成分保留完好,生物相容性良好。     

Implantation of Collagen IV/Poly(2-hydroxyethyl methacrylate) Hydrogels Containing Schwann Cells Into the Lesioned Rat Optic Tract

Poly (2-hydroxyethylmethacrylate) (PolyHEMA) hydrogels, when combined with extracellular matrix molecules and infiltrated with cultured Schwann cells, have the capability to induce CNS axonal regrowth after injury. We have further investigated these PolyHEMA hydrogels and their potential to bridge CNS injury sites. Collagen IV-impregnated hydrogels containing Schwann cells were implanted into the lesioned optic tract in 14 rats. On examination 2–4 months later, there was good adherence between the implants and CNS tissue, and large numbers of viable Schwann cells (S100⁺, GFAP⁺, Laminin⁺, and LNGFR⁺) were seen within the hydrogel matrices. Immunohistochemical analysis showed that the collagen IV-impregnated PolyHEMA hydrogels preferentially supported the transplanted Schwann cells and not host glial cells such as astrocytes (GFAP⁺) or oligodendroglia (CAII⁺). Macrophages (ED1⁺) were also seen within the sponge structure. Eighty-three percent of the implanted hydrogels contained RT97⁺ axons within their trabecular networks. Regrowing axons were associated with the transplanted Schwann cells and not with the small number of infiltrating astrocytes. RT97⁺ axons were traced up to 510 μm from the nearest host neuropil. These axons were sometimes myelinated by the transplanted Schwann cells and expressed the peripheral myelin marker Po⁺. WGA/HRP-labeled retinal axons were seen within transplanted hydrogel sponges, with 40% of the cases growing for distances up to 350–450 μm within the polymer network. The data indicate that impregnating PolyHEMA sponges with collagen IV can modify the host glial reaction and support the survival of transplanted Schwann cells. This study thus provides new information on how biomaterials could be used to modify and bridge CNS injury sites.     

Preparation and evaluation of a biomimetic scaffold with porosity gradients in vitro

A novel biodegradable scaffold based on mimetic a natural bone tissue morphology with a porosity gradient structure was prepared in this paper. The result of surface morphology indicated that a graded porous structure was formed in the fabricated scaffold, where the dense layer (0%) was connected with the most porous layer (60%) by a middling porous layer (30%). To evaluate the degradability, graded porous scaffolds compared with homogeneous scaffolds were placed into a Tris-HCl buffer solution (pH = 7.4) for 28 days. It was found that both scaffolds presented the same degradation trend, and the graded porous structure did not change the original degradability of the scaffold. Moreover, the compressive strength of the graded porous scaffold was better than that of conventional homogeneous scaffold with the increase of degradation time, and the graded porous structure can enhanced the mechanical property of the scaffold. These findings suggest that this biodegradable and porosity-graded scaffold may be a new promising scaffold for loaded bone implant.     

脱细胞软骨基质三维支架的制备及特性研究

[目的]探索脱细胞软骨基质三维多孔支架的制备及其应用于关节软骨组织工程的可行性。[方法]新鲜牛膝关节软骨粉碎后,梯度离心法获取软骨微粒,采用改进的Courtman改良法处理细胞后,再冷冻干燥,制备脱细胞软骨基质三维多孔支架。然后,采用京尼平对三维支架进行交联,再次冷冻干燥后,对支架材料进行大体、组织学染色及扫描电镜观察,分别测定支架的孔隙率、溶胀率、降解率。最后,分离培养兔骨髓基质细胞(BMSCs),采用MTT法检测BMSCs在支架材料上的生长、增殖情况,以柱形图表示。[结果]大体观察显示支架呈疏松多孔状,京尼平交联后整体呈深蓝色。组织学观察显示支架材料无软骨细胞碎片残留,HE染色、甲苯胺兰染色观察均未见软骨细胞残留。测量示支架孔隙率为90%,溶胀率为(1314±337)%,降解率2周为(13.69±7.3)%,4周为(25.99±8.9)%。MTT法显示细胞在支架上生长良好,与对照组DMEM培养液吸光度值比较,差异无统计学意义(P0.05),提示支架无细胞毒性。扫描电镜显示支架内孔洞较明显,BMSCs通过细胞突起黏附于支架表面,黏附良好,能较好地在其上生长。[结论]经改进的Courtman改良法处理的软骨基质三维多孔支架脱细胞更彻底,保留了软骨的天然细胞外基质成分,天然交联剂京尼平交联后支架的细胞相容性好,抗降解性得到了提高,是一种适用于软骨组织工程的良好载体。     

仿生双相磷酸钙生物陶瓷支架的Micro-CT评价

[目的]体外用Micro-CT(Micro-computed tomography)图像对仿生双相磷酸钙生物陶瓷支架的三维结构进行计算机重建和评价.[方法]犬股骨头的松质骨样本行Micro-CT扫描,提取图像信息;三维凝胶叠层成型法制备出具有仿骨小梁结构的双相磷酸钙仿生生物陶瓷支架.随后用Micro-CT对支架扫描,以三维结构参数对支架和松质骨样本作三维评价和比较.三维参数包括:骨体积分数(Bone Volume Fraction,BVF,BV/TV)、骨表面积体积比(Bone surface/bone volume ratio,BS/BV)、骨小梁厚度(Trabecular thickness,TbTh)、骨小梁数目(Trabecular number,TbN)、骨小梁间隙(Trabecular spacing,TbSp)、结构模型指数(Structure Model Index,SMl)和各向异性程度(degree of anisoropy,DA).[结果]与犬股骨头松质骨样本相比,用本方法制备出的BCP支架具有相似的三维空间结构,二者的BV/TV、TbTh、TbN无显著差别(P＞0.05).小梁结构呈板状模型.[结论]本研究制备的BCP多孔支架的小梁具有一定的取向性,力学强度和良好的适于血管长入的空间结构.     

Acute and delayed implantation of positively charged 2-hydroxyethyl methacrylate scaffolds in spinal cord injury in the rat

OBJECT: Hydrogels are nontoxic, chemically inert synthetic polymers with a high water content and large surface area that provide mechanical support for cells and axons when implanted into spinal cord tissue. METHODS: Macroporous hydrogels based on 2-hydroxyethyl methacrylate (HEMA) were prepared by radical copolymerization of monomers in the presence of fractionated NaCl particles. Male Wistar rats underwent complete spinal cord transection at the T-9 level. To bridge the lesion, positively charged HEMA hydrogels were implanted either immediately or 1 week after spinal cord transection; control animals were left untreated. Histological evaluation was performed 3 months after spinal cord transection to measure the volume of the pseudocyst cavities and the ingrowth of tissue elements into the hydrogels. RESULTS: The hydrogel implants adhered well to the spinal cord tissue. Histological evaluation showed ingrowth of connective tissue elements, blood vessels, neurofilaments, and Schwann cells into the hydrogels. Morphometric analysis of lesions showed a statistically significant reduction in pseudocyst volume in the treated animals compared with controls and in the delayed treatment group compared with the immediate treatment group (p < 0.001 and p < 0.05, respectively). CONCLUSIONS: Positively charged HEMA hydrogels can bridge a posttraumatic spinal cord cavity and provide a scaffold for the ingrowth of regenerating axons. The results indicate that delayed implantation can be more effective than immediate reconstructive surgery.