生物型硬脑膜补片在无眼球结膜囊成形术中的应用

目的 研究生物型硬脑膜补片用于无眼球结膜囊成形术中的可行性和临床效果.方法 对12例(12只眼)无眼球结膜囊狭窄患者,采用生物型硬脑膜补片进行结膜囊成形术,术后随访,观察植片植入后的转归及术后结膜囊成形的效果.结果 12只眼术后植入的补片无收缩、脱落、感染及坏死.术后6～12个月,所有植片均被结膜覆盖,术后结膜囊大小深度合适,配戴义眼后外观满意.结论 采用生物型硬脑膜补片修复无眼球结膜囊狭窄是一种安全有效的手术方法.     

角膜体外重构异种生物载体材料植入性实验研究

目的：分析测定异种（猪）角膜基质组织免疫原性，观察其角膜层间植入后与受体角膜愈合情况，以评价该材料生物相容性，并在此载体上体外重构角膜内皮组织，探讨其作为角膜重建载体材料可行性。 方法： (1)将新鲜、脱水两种猪角膜基质植片分别植入F344大鼠角膜基质层间，术后12、90 d对外周血进行CD25和CD4/CD8双色免疫荧光标记，流式细胞仪测定分析。(2)猪角膜基质植入新西兰白兔角膜层间，定期临床观察植片愈合情况，并取受体兔角膜进行组织学观察。(3)将猫角膜内皮细胞接种于保留后弹力层的脱水猪角膜基质上，加入培养液培养7 d，组织学观察体外重构的角膜内皮组织形态结构。 结果： (1)测得新鲜组、脱水组大鼠外周血T淋巴细胞CD4＋CD25＋、CD8＋CD25＋双阳性表达率及CD4＋/CD8＋比值与同基因移植组、阴性对照组比较无显著差异（P>0.05）。(2)兔眼临床观察：全部植片存活，12只术眼未见有角膜水肿混浊、角膜新生血管、排斥反应发生，新鲜植片在2个月左右已透明，脱水植片在6个月后透明。兔角膜组织学观察：新鲜植片4个月时与兔角膜基质相融愈合，脱水植片经角膜细胞再分布、胶原纤维改建重塑于8个月后与兔角膜基质相融愈合，两组植片愈合过程中未见有淋巴细胞浸润及新生血管生成。(3)体外重构的内皮组织形态结构与正常内皮层相似。 结论： 异种（猪）角膜基质免疫原性低，具有良好的生物相容性，是目前较为理想的角膜体外重构载体材料。     

新型生物型硬脑膜补片的安全及有效性

背景：目前应用的硬脑膜修补材料有自体组织修补材料、同种异体材料、异种生物材料和人工合成材料等,主要以进口产品为主,价格昂贵。 目的：通过动物实验评价一种国产新型生物型硬脑膜补片的安全性和有效性。 方法：取24只健康家犬制作双侧硬脑膜缺损模型,左侧植入国产新型生物型硬脑膜补片作为实验组,右侧植入已上市的某品牌人工硬脑膜产品作为对照组。植入后1,3,6,12个月,采用苏木精-伊红染色法比较两组硬脑膜替代物生长、周围组织反应、降解及血管生成情况,荧光分光光度法检测环氧交联剂在犬血液及脑脊液的残留情况。 结果与结论：在植入1-12个月期间,实验动物生长状况良好,未见感染和运动障碍等并发症。病理切片显示两组硬脑膜替代材料生物相容性良好,无炎症或仅有轻微炎症反应;植入6个月,实验组补片表层已经退化,并形成由原植入物胶原纤维与新生结缔组织交织在一起的“过渡态结构”,对照组材料无降解;植入12个月,实验组补片有近50%降解,替代材料有新生血管生成,对照组降解30%,仅少量样本可见新生血管。术后1,3,7,14 d,犬血液和脑脊液均未检出交联剂环氧化合物。实验表明这种新型生物型硬脑膜补片是一种安全、有效的理想硬脑膜修补材料。     

联合两种成体干细胞快速构建组织工程骨在植骨融合中的应用

背景：尽管应用一种干细胞进行组织修复已取有重大进展,但联合两种或多种干细胞构建组织工程骨的研究尚不多见。 目的：观察脂肪干细胞联合骨髓间充质干细胞/异体骨植入兔腰椎后路横突间植骨融合模型的骨修复效果。 方法：新西兰大白兔75只,随机分为5组,分别在各组兔L5、L6腰椎横突融合模型中做以下处理：①植入骨髓间充质干细胞/异体骨复合骨条,周围注入脂肪干细胞悬液。②植入骨髓间充质干细胞/异体骨复合骨条,周围注入生理盐水。③单纯植入异体骨条,周围注入脂肪干细胞悬液。④单纯植入异体骨条,周围注入生理盐水。⑤植入自体骨条。术后1,3,5周用PET/CT对各组动物行全身显像,比较各组植骨区SUV值。 结果与结论：各组植骨区PET/CT图像均显示了不同程度的骨融合和骨代谢增强。各组植骨区SUV值随时间增加而增高,但单纯异体骨组3个时间点的SUV值差异无显著性意义(P > 0.05),其他各组第3周和第5周时SUV值均高于第1周(P < 0.05),且第3周与第5周差异无显著性意义(P > 0.05)。术后第3周,脂肪干细胞联合骨髓间充质干细胞/异体骨组的SUV值优于骨髓间充质干细胞/异体骨组和自体骨组,差异有显著性意义(P < 0.05),说明联合脂肪干细胞和骨髓间充质干细胞快速构建组织工程骨具有良好的成骨和血管化作用。   中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程     

脱细胞异种生物外科补片的免疫原性

文题释义：免疫原性：指能够刺激免疫系统的细胞引起某种抗原特异性免疫应答。当动物源性材料植入人体后,其细胞表面的α-Gal抗原与人体内存在的天然抗α-Gal抗体结合,会激活补体系统引起严重的超急性排斥反应;还可通过抗体依赖细胞介导的细胞毒性作用,引起异种移植排斥反应。对于异种材料植入人体所产生的潜在风险,有必要对其进行免疫原性风险评估。脱细胞技术：指通过物理、化学、生物学等一系列的方法处理同种异体的组织、器官,使其细胞内基质除去完全而保留相应的细胞外基质的方法。脱细胞技术可降低甚至除去异体组织、器官的免疫源性(如α-Gal抗原)等,降低异体生物材料移植引起的排斥反应,为异体生物材料的临床运用提供基础。背景：脱细胞异种生物外科补片的免疫原性直接关系到其植入人体后的成功与否,因而评价材料的免疫原性至关重要。 目的：评价脱细胞异种生物外科补片的免疫原性。 方法：将20只Balb/c小鼠随机分4组,每组5只：实验组与对照组背部皮下分别植入脱细胞异种生物外科补片与心包膜原材料;阴性对照组行假手术操作;阳性对照组背部皮下注射弗氏佐剂和牛血清白蛋白等体积混合液。植入4周后,记录小鼠体质量,计算各组脾脏和胸腺的脏脑系数,检测血清总IgG和IgM水平、体外淋巴细胞增殖活性及脾脏淋巴细胞亚型分布,并进行植入部位皮肤组织及脾脏、胸腺组织病理学观察。实验方案经四川省食品药品检验检测院安全评价中心实验动物管理和使用委员会批准(IACUC-2018-KYYL-008)。结果与结论：①实验组与阴性对照组体质量比较差异无显著性意义(P > 0.05),对照组大于阴性对照组(P < 0.05);②实验组与阴性对照组脾脏脏脑系数、胸腺脏脑系数比较差异均无显著性意义(P > 0.05),对照组脾脏脏脑系数大于阴性对照组(P < 0.05);③实验组与阴性对照组淋巴细胞增殖活性比较差异无显著性意义(P > 0.05),对照组高于阴性对照组(P < 0.05);④与阴性对照组相比,实验组CD3⁺CD8⁺细胞百分比降低(P < 0.05);与阴性对照组相比,对照组CD3⁺细胞、CD3⁺CD4⁺细胞、CD3⁺CD8⁺细胞、CD45⁺SSClow细胞百分比下降(P < 0.05),CD3^-CD19⁺细胞百分比升高(P < 0.05);⑤实验组、对照组血清IgM和IgG抗体水平与阴性对照组相比差异均无显著性意义(P < 0.05);⑥组织学显示,实验组与对照组脾脏和胸腺无明显病理改变,实验组植入部位无明显炎性反应,对照组植入部位出现严重肉芽肿性炎及纤维组织增生包裹、植入物坏死崩解等;⑦结果表明与原材料相比,经脱细胞处理的异种生物外科补片可有效降低免疫原性反应。ORCID: 0000-0003-3480-6101(程祥) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

凝胶包埋骨髓基质干细胞复合脱钙骨基质修复关节软骨缺损

目的探索Ⅱ型胶原凝胶包埋的自体骨髓基质干细胞(BMSCs)接于同种异体脱钙骨基质(DBM)材料修复兔关节软骨缺损的效果。方法15只健康成年新西兰大白兔,雌雄不限,体质量约3.0 kg,兔龄6~9个月;以Urist方法制作同种异体DBM材料。以Ⅱ型胶原蛋白配制水凝胶,以水凝胶包埋兔BMSCs并接种于同种异体DBM材料,构建组织工程复合物。在新西兰大白兔股骨髁关节面制造软骨缺损,分组进行修复。将健康成年新西兰大白兔27只(雌雄不限,体质量约2.5 kg,兔龄3~4个月)共54侧膝关节随机分为Ⅱ型胶原/DBM/BMSCs修复组(实验组)、Ⅱ型胶原/DBM修复组(实验对照组)及空白对照组。于术后4周、8周及12周各处死9只动物,取材对修复组织进行大体及组织学观察,根据Wakitani法对修复组织进行评分,数据输入SPSS 11.5软件进行统计学分析,比较各组的评分差异是否具有统计学意义。结果实验组Ⅱ型胶原/DBM/BMSCs植入后形成透明软骨样修复,表面光滑平坦,与周围软骨及软骨下骨结合良好;实验对照组Ⅱ型胶原/DBM植入后有部分软骨样修复;而空白对照组仅有少量纤维性修复。根据组织学评分标准,实验组组织学评分为(20.25±1.64)分,高于实验对照组[(7.46±1.29)分]及空白对照组[(6.00±2.09)分]。结论Ⅱ型胶原自体BMSCs复合同种异体DBM支架材料修复全层关节软骨缺损的效果良好,是一种修复软骨缺损的行之有效的方法。     

异基因组织工程骨修复猪胫骨缺损术后外周血T淋巴细胞亚群的检测

目的 通过检测异基因组织工程骨移植修复猪胫骨缺损术后T淋巴细胞亚群CD4 和CD8 细胞的变化,探索异基因组织工程骨的免疫原性.方法 骨髓间充质干细胞(MSCs)体外培养,扩增,诱导成骨后与磷酸三钙(TCP)复合为组织工程骨,分自体和同种异体组,植入构建好的猪胫骨中段2.0 cm的缺损处,对照组为纯TCP组,流式检测术前,术后3、7、14、28、56 d外周血T淋巴细胞亚群变化.结果 小型猪外周血T淋巴细胞亚群分别为CD4 (9.37±1.65)%,CD8 (38.43±1.62)%,CD4 CD8 (7.23±1.24)%;术后组内不同时间点CD4 和CD8 细胞测定值无显著变化,CD4 CD8 双阳性细胞在3 d和7 d增加明显(P＜0.05);组间各时间点CD4 、CD8 和CD4 CD8 细胞无显著变化.结论 术后T细胞亚群检测结果显示无明显的免疫排斥,推论异基因组织工程骨免疫原性低.     

兔腰椎前柱间盘切除后髓核组织对椎体间植骨融合的影响

背景：文献报道腰椎融合治疗腰椎疾病,有近20%不能达到有效的融合,出现治疗后疼痛、椎间隙塌陷、迟发性后凸畸形等一系列并发症。 目的：进一步验证兔腰椎前柱结构切除后髓核组织对椎体间植骨融合效果。 方法：健康成年日本大耳白兔36只,随机分为3组,每组12只。①剥离前纵韧带+植骨组在L3间盘水平剥离前纵韧带,使其与L3间盘前缘形成间隙,植入同种异体髂骨。②切除1/3间盘组织+植骨组切除L3前1/3间盘组织,终板间植入同种异体髂骨,缝合同剥离前纵韧带+植骨组。③切除1/3间盘组织+内固定组在切除1/3间盘组织+植骨组的基础上行前柱的内固定。 结果与结论：生物力学测定：剥离前纵韧带+植骨组治疗后12周融合节段垂直拉伸力明显优于其他2组,能够承受更强的外界拉伸力。腰椎侧位X射线检查：切除1/3间盘组织+植骨组12周植入骨块吸收,椎间隙无新生骨长入;切除1/3间盘组织+内固定组12周椎间有连续骨桥形成;剥离前纵韧带+植骨组12周完全骨性融合。组织学观察：切除1/3间盘组织+植骨组12周未见骨组织生成;切除1/3间盘组织+内固定组12周少量的成熟骨小梁及成骨细胞;剥离前纵韧带+植骨组12周大量成熟骨小梁及骨细胞,重塑后的板状骨及哈弗氏结构。结果证实腰椎前柱的稳定性对椎体间植骨融合的效果有显著的影响,切除前1/3间盘组织后,游离的间盘、髓核物质影响了植入骨融合,有效地恢复前柱稳定性能够促进椎体间植骨融合,但仍不能达到有效融合。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

人工硬脑膜补片对开颅手术脑组织复位分析

目的探究人工硬脑膜补片在开颅手术患者术后脑组织复位中的应用价值。方法在2015年5月~2017年10月来我院神经外科收治的接受开颅手术治疗患者中选出140例,以随机数表法分成两组,对照组患者采用自体骨膜修补减张缝合术,观察组患者选择生物型人工硬脑膜补片减张缝合,对比两组的手术指标。结果手术时间、术中出血量:观察组较对照组少,P0.05;术后随访3个月并发症发生率,观察组较对照组低,P0.05;术后6个月GOS评测预后,观察组预后好于对照组,P0.05。结论对于开颅手术患者存在硬脑膜缺损的患者,相较于自体骨膜修补,生物型人工硬脑膜补片以其良好的组织相容性和致密性可维持硬脑膜完整,保护脑组织,值得推广。     

新西兰兔下颌骨牵引成骨早期拆除牵引装置植入钛钉对新骨形成的影响

目的：利用锥形束CT（ CBCT）研究新西兰兔下颌骨矩形截骨后,早期拆除牵引装置植入钛钉对新骨形成 的影响,探讨牵引成骨早期拆除牵引装置的可能性。方法：新西兰兔下颌骨矩形截骨12 mm×4 mm,植入自制牵 引装置。牵引5 d 后,随机分为稳定4 周、稳定8 周、钛钉植入3 组。前2 组分别于稳定期4 周、8 周时处死动物;钛 钉植入组,稳定期4 周时,取出牵引器植入钛钉,4 周后处死动物;拍摄CBCT和X线片。结果：兔下颌骨垂直高 度平均增加（2.25±0.41）mm。稳定4 周、8 周和钛钉植入组的术区CT值分别为（80.00±12.36）Hu、（293.00±37.66） Hu和（289.25±38.87）Hu。稳定4 周术区CT值低于稳定8 周和钛钉植入组,后2 组CT值相近。结论：早期拆除 牵引装置植入钛钉与常规固定相比,骨形成没有明显影响,临床应用可有效地缩短牵引成骨的时间。     

新型猪心包源硬脑膜修补材料的实验研究

目的 评价新型猪心包源人工硬脑膜材料用于修补缺损硬脑膜的可行性及安全性.方法 36只新西兰兔按完全随机法分3组:A组(实验组,猪心包源人工硬脑膜修补材料组)、B组(自体颅骨骨膜组)和C组[膨体聚四氟乙烯(e-PTFE)硬脑膜组],每组12只.构建硬脑膜缺损动物模型,分别应用猪心包源人工硬脑膜修补材料、自体颅骨骨膜、e-PTFE硬脑膜行硬脑膜缺损修补.每组动物分别于术后30、90、180d各处死4只,并于术前及处死前采集兔静脉血行白细胞、淋巴细胞计数.处死后于修补材料部位采集标本行组织学检查,对比观察分析植入材料局部细胞浸润及局部蛛网膜、硬脑膜下腔和脑皮质情况.结果 3组动物术后无脑脊液漏发生及并发症出现.A、B、C组动物术前白细胞数[(6.94±0.39)、(6.94±0.60)、(6.94±0.41)个/mm2]和淋巴细胞计数[(4.77±0.41)、(4.61±0.57)、(4.78±0.39)个/mm2]与术后白细胞数[(7.01±0.49)、(6.75±0.26)、(7.20±0.49)个/mm2]和淋巴细胞数[(4.60±0.55)、(4.54±0.26)、(4.46±0.76)个/mm2]差异均无统计学意义(P>0.05).3组植人材料与脑皮层粘连等不良反应差异均无统计学意义(P>0.05).病理观察3组的硬脑膜修补部位无变性、包裹、钙化,局部炎性细胞浸润差异也无统计学意义(P>0.05).结论 新型猪心包源人工硬脑膜是一种安全、可行的硬脑膜修补材料.     

Bone grafts cultured with bone marrow stromal cells for the repair of critical bone defects: an experimental study in mice

Tissue engineering of autologous bone combined with osteoprogenitor cells is a suitable strategy for filling large bone defects. The aim of this study was to evaluate the osteogenicity of a xenogenic bone graft cultured with allogenic bone marrow stromal cells (BMSC) in a mouse critical size craniotomy. Bovine trabecular bone grafts were made free of bone marrow cells or debris and were delipidated. BMSC were harvested from C57BL/6-Tg(ACTbEGFP)1Osb/J mice (GFP+ cells) and were cultured 14 days on bone grafts in control or osteogenic medium. Engineered grafts were implanted in calvarial defect in C57BL/6 mice. Four groups were studied: graft with BMSC differentiated in osteoblasts (G-Ob), graft with BMSC (G-BMSC), graft without cells (G) and no graft. Calvariae were studied 2 and 8 weeks after implantation by radiographic and histomorphometric analyses. G group: the bone ingrowth was limited to the edges of the defect. The center of the graft was filled by a fibrovascular connective tissue. G-BMSC or G-Ob groups: bone formation occurred early in the center of the defect and did not increase between 2 and 8 weeks; the newly formed woven bone was partially replaced by lamellar bone. The preoperative osteoblastic differentiation of BMSC did not allow faster and better bone regeneration. After 2 weeks, GFP+ cells were observed around the grafted bone but no GFP+ osteocyte was present in the newly formed bone. No GFP+ cell was noted after 8 weeks. However, pre-implantation culture of the biomaterial with allogenic BMSC greatly enhanced the bone regeneration.     

In vivo performance of a phospholipid-coated bioerodable elastomeric graft for small-diameter vascular applications

There remains a great need for vascular substitutes for small-diameter applications. The use of an elastomeric biodegradable material, enabling acute antithrombogenicity and long-term in vivo remodeling, could be beneficial for this purpose. Conduits (1.3 mm internal diameter) were obtained by electrospinning biodegradable poly(ester urethane)urea (PEUU), and by luminally immobilizing a non-thrombogenic, 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymer. Platelet adhesion was characterized in vitro after contact with ovine blood. The conduits were implanted as aortic interposition grafts in the rat for 4, 8, 12, and 24 weeks. Surface treatment resulted in a 10-fold decrease in platelet adhesion compared to untreated material. Patency at 8 weeks was 92% for the coated grafts compared to 40% for the non-coated grafts. Histology at 8 and 12 weeks demonstrated formation of cellularized neotissue consisting of aligned collagen and elastin. The lumen of the grafts was confluent with cells qualitatively aligned in the direction of blood flow. Immunohistochemistry suggested the presence of smooth muscle cells in the medial layer of the neotissue and endothelial cells lining the lumen. Mechanically, the grafts were less compliant than rat aortas prior to implantation (4.5 ± 2.0 × 10(-4) mmHg(-1) vs. 14.2 ± 1.1 × 10(-4) mmHg(-1) , respectively), then after 4 weeks in vivo they approximated native values, but subsequently became stiffer again at later time points. The novel coated grafts exhibited promising antithrombogenic and mechanical properties for small-diameter arterial revascularization. Further evaluation in vivo will be required to demonstrate complete remodeling of the graft into a native-like artery.     

J2对同种异体穿透性角膜移植模型大鼠CD4+和CD8+T细胞免疫功能的抑制

BACKGROUND: J2 takes functional domain (MHC CD4-D1/) of complex conjugate of CD4 molecule and MHC class II molecule as a target, and is a small molecule compound obtained by computer screening from a chemical data containing hundreds of thousands of organic compounds. In the previous study, J2 was used in mouse models of skin transplantation and keratoplasty by oral and intraperitoneal injection. Results verified that J2 could prolong the survival time of grafts, and suppress occurrence of rejection. To better play the role of a drug targeting and to reduce systemic toxicity, J2 will be further utilized in local treatment of keratoplasty rejection. OBJECTIVE: To investigate the inhibitory effect of new immunosuppressive agent J2 on CD4+ and CD8+ T cell immune functions in rat models receiving allogenic penetrating keratoplasty. METHODS: Allogeneic penetrating keratoplasty model was established using the adult female Wistar rats as donors and Sprague-Dawley rats as recipients. Group A: normal Sprague-Dawley rats were injected with 0.05 mL placebo subconjunctivally. Surgery rats were randomly divided into three groups. Group B: allograft rats were injected with 0.05 mL placebo subconjunctivally after autologous keratoplasty. Group C: allograft rats were injected with 0.05 mL placebo subconjunctivally. Group D: allograft rats were injected with 1% J2-nanosuspension 0.05 mL subconjunctivally. The distribution of T cell subsets in peripheral blood was detected using flow cytometry at 3 days, 1, 2 and 3 weeks after transplantation and compared among groups.  RESULTS AND CONCLUSION: There was no significant difference in total CD3+ T cells, CD4+ T cells, CD8+ T cells and CD4+/CD8+ in peripheral blood lymphocytes in group B at various time points. At 3 days and 1 week after surgery in group C, no significant difference in total CD3+ T cells, CD4+ T cells and CD8+ T cells was detected. At 1 and 2 weeks, the number of total CD3+ T cells, CD4+ T cells and CD8+ T cells increased, showing significant differences (P < 0.05). In group D, no significant hyperplasy was found in CD4+ T cells and CD8+ T cells at 1 and 2 weeks. The horizontal comparison of the same time point: the total CD3+ T lymphocytes of group D was significantly less than group C at 3 days, 1 and 2 weeks after operation (P < 0.05), whereas there was no significant difference at 3 weeks between the group D and group C. The number of CD4+ T lymphocytes in group D was less than in group C at 3 days and 1 week, but with no significant difference. The ratio of CD4+/CD8+ had no significant difference in group D compared with group C at 3 days, 1 and 3 weeks. J2 inhibits T lymphocyte proliferation and then inhibits T cell-mediated corneal allograft rejection.       

天然牡蛎壳纳米体复合型骨材料修复骨缺损

背景：研究发现,牡蛎壳等很多海洋生物外壳等形成矿物质盐的过程与人体实际情况较为接近。 目的：观察天然牡蛎壳纳米体复合型骨材料修复骨缺损的效果。 方法：取30只成年大耳白兔,制作双侧桡骨骨缺损模型,随机均分为两组,实验组于骨缺损处植入天然牡蛎壳纳米体复合型骨材料,对照组于骨缺损处植入医用硫酸钙可注射型植骨材料,植入后2,8,12周进行X射线检查,了解植入骨材料周围组织生长结合情况;于第12周末获得双侧桡骨,利用生物力学测试系统检测桡骨抗弯曲强度,并利用彩色图像分析仪定量分析成骨情况。 结果与结论：植入后2周,两组骨材料密度较周边正常骨组织呈偏低,缺损与材料间边界清晰,未发现明显骨修复现象;植入后8周,两组骨材料均被较厚软组织全部包裹,实验组血管成分显著减少;植入后12周,两组骨材料紧密结合相邻组织,包裹骨材料的组织质地较韧,二者之间无界线,实验组桡骨表面形态已恢复至正常水平,在形态和质地结构方面与正常组织无明显区别,对照组仍存在明显投射分界影像。实验组桡骨抗弯曲强度和成骨量均显著大于对照组(P < 0.05)。表明天然牡蛎壳纳米体复合型骨材料修复骨缺损可以获得更好的桡骨抗弯曲强度,并促进新骨形成。     

Temporal pattern of host responses against intrastriatal grafts of syngeneic,allogeneic or xenogeneic embryonic neuronal tissue in rats

The host response to immunologically incompatible intrastriatal neural grafts was studied using immunohistochemical techniques. Dissociated ventral mesencephalic tissue from embryonic donors of either syngeneic, allogeneic or xenogeneic (mouse) origin was stereotaxically implanted into adult rats. The brains were analysed 4 days, 2 weeks or 6 weeks after grafting with antibodies against the following antigenic structures: major histocompatibility complex (MHC) class I antigens; MHC class II antigens; complement receptor (CR) 3 (marker for microglia and macrophages); helper T-lymphocyte antigen-cluster of differentiation (CD) 4; cytotoxic T-lymphocyte antigen-CD8; tyrosine hydroxylase (TH) (marker for transplanted dopaminergic neurons). The number of surviving TH-positive cells was not different at the various time points in either the syngeneic or allogeneic groups, whereas the xenogeneic cells were all rejected by 6 weeks.The host reactions were similar in character in the syngeneic and allogeneic groups. At 4 days after implantation, there were increased levels of expression of MHC class I and II antigens. In and around the grafts, there were cellular infiltrates consisting of activated microglia, macrophages, CD4- and CD8-positive lymphocytes. At 6 weeks, MHC expression was reduced and the cellular infiltrates had subsided with only low numbers of activated microglia cells and CD8-positive lymphocytes remaining. In the xenogeneic group, at 4 days, some grafts contained cavities, possibly reflecting acute rejection. At later stages, the xenografts were heavily infiltrated by macrophages, activated microglial cells and T-lymphocytes, and at 6 weeks all the xenografts were rejected.Taken together, the results suggest that there is an inflammation caused by the implantation process which leads to an accumulation of host defence cells. This, in turn, leads to increased MHC expression in and around the grafts. In syngeneic grafts, these reactions are short lasting and weak; for allografts slightly more pronounced and longer lasting than syngeneic grafts, but not sufficient to cause rejection. For xenografts, the reactions are more intense and lead to transplant rejection. Thus, a strong sustained inflammatory response may be an important determinator for the failure of histoincompatible neural grafts. It can be speculated that a short-term anti-inflammatory treatment of graft recipients may be a sufficient immunosuppressive regimen to allow long-term graft survival.     

组织型纤溶酶原激活剂在移植血管桥再狭窄动物血管的差异表达

目的研究组织型纤溶酶原激活剂（t—PA／PLAT）在移植血管桥再狭窄动物血管的差异表达。方法通过兔双侧颈动脉进行动脉桥和静脉桥的移植,形成双侧移植血管桥再狭窄动物模型。应用免疫组化检测t-PA在动物模型动脉桥、静脉桥的表达并进行比较。结果血管桥移植前,t-PA在实验动物颈动脉和颈静脉的表达差异无统计学意义（P〉0．05）;血管桥移植后,t-PA在动脉桥的表达明显高于静脉桥（P〈0．05）,于16周时达到高峰[（32．34±4．74）％比（16．74±3．14）％],以后随时间延长而出现表达减少（P〈0．05）。结论t-PA在术后早期对血管桥具有保护作用,其表达的高低与术后血管桥再狭窄关系密切。     

Improved endothelialization and reduced thrombosis by coating a synthetic vascular graft with fibronectin and stem cell homing factor SDF-1α

Failure of synthetic small-diameter vascular grafts is determined mainly by the lack of endothelial cells, as these cells inhibit thrombosis and intimal hyperplasia. Coating of graft material with homing factors for circulating stem cells has the potential to improve endogenous endothelialization of these grafts and to reduce graft failure. Synthetic knitted polyester grafts (6mm diameter) were coated with FN and SDF-1α before surgical interposition in the carotid artery of sheep. Similar uncoated vascular grafts were implanted in the contralateral side as internal controls. To study the early attraction of stem cells, grafts were implanted in a first series of nine sheep and explanted after 1 or 3 days. In coated grafts, four times higher fractions of CD34(+) and three to four times higher fractions of CD117(+) cells adhering to the vessel walls were found than in control grafts (P<0.05). When such coated and non-coated grafts were implanted in 12 other sheep and explanted after 3 months, all coated grafts were patent, while one control graft was occluded. EcNOS staining revealed that FN-SDF-1α coating significantly increased coverage with endothelial cells from 27 ± 4% of the graft to 48 ± 4% compared with the controls (P=0.001). This was associated with a significant reduction of intimal hyperplasia (average thickness 1.03 ± 0.09 mm in controls vs. 0.69 ± 0.04 mm in coated grafts; P=0.009) and significantly less adhesion of thrombotic material in the middle part of the graft (P=0.029). FN-SDF-1α coating of synthetic small-caliber vascular grafts stimulated the attraction of stem cells and was associated with improved endothelialization and reduced intimal hyperplasia and thrombosis.