半月板内部微血管的初步研究

在2例新鲜足月胎儿尸体上,用墨汁灌注的方法研究了半月板的微血管结构。半月板外侧的60％为血管区,内侧的40％为少血管区。半月板的撕裂常发生于血管区与少血管区的交界处。半月板外缘丰富的血管是半月板修复的解剖学础基。     

半月板无血管区急性纵形损伤中成纤维细胞的定量分析

采用在活体关节腔内~3氚—胸腺嘧啶核苷(~3H—TdR)单标记放射自显影方法,观察用环锯钻洞法治疗半月板无血管区急性纵形损伤后肉芽组织修复中细胞成份的形态变化,用图象分析仪对不同愈合时期肉芽组织中不同功能状态的纤维细胞随机进行几何参数的测试,为临床采用最佳方法治疗半月板损伤提供可靠依据。     

多孔型丝素蛋白/羟基磷灰石复合骨髓间充质干细胞修复兔半月板无血运区软骨损伤

背景：随着组织工程的兴起,半月板无血运区损伤的修复可能性显著地提高,但单一的支架材料均不能符合理想支架的要求,有一定的局限性。 目的：观察丝素蛋白/羟基磷灰石复合骨髓间充质干细胞修复兔半月板无血运区软骨损伤的效果。 方法：体外分离培养兔骨髓间充质干细胞,并定向诱导成纤维软骨细胞,与丝素蛋白/羟基磷灰石复合培养。42只构建半月板无血运区软骨损伤模型成功的大白兔随机抽签法均分为3组,复合材料组植入骨髓间充质干细胞-丝素蛋白/羟基磷灰石复合物;单纯材料组植入丝素蛋白/羟基磷灰石;对照组不行任何干预。 结果与结论：复合材料组大体观察损伤被修复组织填充,8~12周效果逐渐改善,与正常半月板组织相似,优于其他两组;组织学检查显示8周时出现软骨囊和排列紊乱的胶原纤维,12周时完全修复了半月板损伤区,表现为纤维软骨样组织愈合;单纯材料组部分修复了半月板损伤区,呈瘢痕愈合,对照组未见软骨修复。MRI检查显示复合材料组修复效果较好;说明丝素蛋白/羟基磷灰石复合骨髓间充质干细胞可有效地修复半月板无血运区缺损。丝素蛋白/羟基磷灰石材料作为半月板软骨组织工程支架材料的良好生物相容性。     

重组碱性成纤维细胞生长因子/Ⅰ型胶原复合材料修复兔半月板无血运区软骨损伤

背景:单独应用重组碱性成纤维细胞生长因子对无血运区半月板损伤的愈合无明显影响,考虑主要与其在体内易被吸收和降解等有关。近年来Ⅰ型胶原作为生物性载体的应用逐渐增多。目的:观察重组碱性成纤维细胞生长因子/Ⅰ型胶原复合材料修复兔半月板软骨损伤的效果。方法:选用健康新西兰大白兔36只,首先在兔半月板上造成统一的无血运区损伤模型。随机分为空白对照组、重组碱性成纤维细胞生长因子组和重组碱性成纤维细胞生长因子/Ⅰ型胶原组。术后2,6,12周分批处死实验动物,进行大体形态观察和组织学检查。结果与结论:重组碱性成纤维细胞生长因子组对无血运区损伤愈合无明显影响,但对半月板边缘滑膜中成纤维细胞有明显的促增殖作用;重组碱性成纤维细胞生长因子/Ⅰ型胶原组表现为纤维软骨样组织愈合,但其愈合组织与正常半月板组织仍有差异。结果表明应用重组碱性成纤维细胞生长因子/Ⅰ型胶原复合型材料治疗半月板无血运区的损伤是一种有效的治疗方法。     

组织工程材料修复半月板运动损伤的可行性及特点

背景：组织工程技术的发展为半月板损伤的修复和再造开辟了新的途径,利用该技术构建有功能的半月板在防治半月板切除后的并发症中有重要意义。 目的：综述了组织工程材料在半月板运动损伤修复中的可行性及特点。 方法：由第一作者检索1990/2010 PubMed数据库及中国知网数据库有关天然生物材料、人工合成材料、纳米材料修复半月板损伤的文章。英文检索词为“meniscus,sports injuries,repair,tissue engineering,material ”,中文检索词为“半月板,运动损伤,修复,组织工程,支架材料”。 结果与结论：由于半月板的血供特点,致使半月板无血运区损伤不具备愈合能力。组织工程技术的发展为半月板损伤的修复和再造开辟了新途径。目前报道较多的修复半月板支架材料主要有天然生物材料、人工合成材料、纳米材料等。组织工程化半月板的研究已取得了阶段性的成果,但对支架材料正处于研发实验阶段,还没确定出一种最理想的材料,因此寻求一种具有良好的细胞相容性,可控制的降解率并具有一定力学强度的支架材料仍是半月板组织工程的研究热点。     

鞘内屈肌腱的生物力学特性

本文观察了狗肌腱的组织结构,并在生物软组织力学试验台上.对狗鞘内屈指肌腱进行了一维载荷的力学试验.肌腱受压擦区呈现软骨样组织增生.肌腱血管区与无血管区在组织结构上和力学特性上无明显差异.肌腱 Young's 模量(dT/dλ)随张应力(T)的增大而变大.其一维本构方程为指数函数关系.肌腱抗张强度平均在7.20～13.87kg/mm~2.     

半月板的纤维构筑及其与损伤的关系

取足月胎儿,3～5岁小儿及成人半月板各10例,从组织切片、扫描电镜显示,半月板内有纵向和横间纤维。纵向纤维量多,拧集成束,体部内的纤维束集合成纤维板层。纵向纤维的抗拉力强,因而横断损伤少见。横向纤维量大,集中成五层,分布于半月板体部的上、下表面及纵向纤维板层之间。横向纤维弱,受力后易断裂,形形半月板的纵向撕裂。严重慢性磨损易致半月板中央横向纤维层退变,形成水平劈裂。     

趾屈肌腱微血管的应用解剖

通过血管注射，对成人新鲜尸体下肢２２侧趾屈肌腱的微血管进行了研究。肌腱的血供主要来自肌支、腱旁组织、腱系膜与腱纽的血管和骨－腱接合处来自骨和骨膜的血管。肌腱鞘外段的腱内血管以束间吻合管为主，分布均匀，与腱外膜血管丛的横支互相连接。肌腱鞘内段的血管呈节段性分布于系膜侧，而对系膜侧为无血管区。拇长、趾长屈肌腱在跖趾关节和近侧趾间关节平面分别为无血管段或相对无血管段。对肌腱血供的临床意义进行了讨论。     

运动性半月板损伤及组织工程半月板的应用

背景：半月板损伤是常见的膝关节运动损伤之一,常伴有关节软骨的损伤,其原因是膝关节内环境的紊乱。 目的：评价组织工程半月板在半月板构建中的生物支架材料的性能,以寻求合理的半月板替代物。 方法：以“组织工程;半月板修复;生物材料支架;运动性半月板损伤”为中文关键词,以“tissue engineering, the meniscus repair,biological material scaffold; athletic meniscal injury”为英文关键词,应用计算机检索维普数据库(1994-01/2009-12)和Pubmed数据库(1994-01/2009-12),纳入30篇运动性半月板损伤和组织工程半月板相关的文献。对半月板组织的特征、半月板组织工程种子细胞的来源、组织工程半月板支架材料生物相容性和可降解性以及细胞因子在组织工程半月板构建过程中的作用进行综合评价。 结果与结论：与传统半月板修复相比,组织工程化半月板具有无抗原性,来源不受限制,可按预先设计塑型,具有生命力等许多优点。但是组织工程化半月板仍有许多问题有待研究和解决,如何模拟体内环境,在体外成功构建半月板组织,如何提高支架材料的应用性,研制具有与正常人体半月板组织相接近的力学性能的支架材料是一个半月板修复的关键性问题。     

半月板的生物力学及其损伤修复的研究进展

临床工作中,在膝关节创伤时,经常会遇到半月板损伤。在现今,人们对半月板的生物力学功能进行许多研究（3-9）,越来越认识到半月板的生物力学功能重要性,认为不宜简单地将损伤半月板切除,而应修复它们,但半月板无血液供应区的损伤修复后不能愈合,这是骨科界的难题之一,为此人们亦进行了许多研究（10-16）。一. 半月板的大体形态、血液供应、显微镜下形态、生化等 半月板是介于股骨髁和胫骨平台之间的半月状软骨,其外侧缘较厚,内侧缘较薄,内侧半月板呈“c"形,外侧半月板近似呈“o"形。内侧半月板前角胫骨韧带止点附着于前交叉韧…     

膝关节动脉的血液供应

本文通过动脉灌注,对120侧不同年龄(新生儿至87岁)尸体的膝关节骨性部和软组织的血液供应分别进行了研究。新生儿的膝动脉在软骨内分布呈节段性,软骨骨化后,骨骺和髌骨的动脉间建立广泛的吻合。骺软骨板分隔膝关节的骨骺与干骺端。随骺板的闭合,两者间有血管互相交通。骺板的血液供应来自骺动脉、干骺动脉和滋养动脉终末的毛细血管袢以及骨膜动脉网的小支。髌骨的动脉分3组,发自髌前丛和髌周动脉环。滑膜和髌下脂垫的血管分布丰富。肌睫和韧带在骨的附着处缺乏血管。成人半月板外1/5有血管分布,内4/5无血管。本文对膝关节血管分布的临床意义作了简要讨论。     

A porous polymer scaffold for meniscal lesion repair--a study in dogs

Meniscal lesions often occur in the avascular area of the meniscus with little chance of spontaneous repair. An access channel in the meniscal tissue can function as an entrance for ingrowing repair tissue from the vascular periphery of the meniscus to the lesion in the avascular zone which again induced healing of the lesion. Implantation of a porous polymer in a full-thickness access channel induced healing. However, a better integration between meniscal tissue and the implant might be achieved with the combination of the newly developed porous polymers and a modified surgical technique. This might improve meniscal lesion healing and the repair of the access channel with neo-meniscal tissue. Longitudinal lesions were created in the avascular part of 24 canine lateral menisci and a partial-thickness access channel was formed to connect the lesion with the meniscal periphery. In 12 menisci, the access channel was left empty (control group), while in the remaining 12 menisci the polymer implant was sutured into the access channel. Repair of the longitudinal lesions was achieved with and without polymer implantation in the partial-thickness access channel. Polymer implants induced fibrous ingrowth with cartilaginous areas, which resembled neo-meniscal tissue. Implantation did not prevent articular cartilage degeneration.     

Locally applied angiogenic factors – a new therapeutic tool for meniscal repair

Tears in the peripheral part of the menisci have a better healing potential than tears in the central part, because the central two-thirds of the menisci are avascular. The avascular status of the meniscus is maintained by the expression of antiangiogenic factors such as endostatin. The distribution of endostatin in the menisci correlates with the degree of vascularization. Endostatin immunostaining is strong in the avascular zone and reduced in the vascularized outer one-third. Endostatin interacts with signal transduction of the vascular endothelial growth factor (VEGF) by reducing VEGF-induced kinase (Erk1/2) phosphorylation. VEGF plays an important role in angiogenesis in fetal menisci and it is down-regulated in the adult meniscus.

We hypothesized that healing of meniscal tears in the avascular zone can be promoted by the local application of the angiogenic factor VEGF. To evaluate this hypothesis a tear was created in the avascular zone of the medial meniscus in 18 merino sheep. The tear was then repaired with an uncoated suture (group 1), a suture coated with PDLLA (group 2), and by a suture coated with PDLLA/VEGF (group 3).

After 6 weeks we observed increased factor VIII immunostaining in the VEGF-treated group. However, in this treatment group (VEGF/PDLLA) no meniscus healed. In the uncoated suture group and in the PDLLA-coated suture group partial healing was observed in three animals and complete healing in three animals, respectively. Factor VIII expression is normally restricted to vascular endothelial cells. In this study, however, single endothelial cells could be detected in the menisci of the VEGF/PDLLA group. This finding suggests that the application of VEGF might have stimulated proliferation of vascular endothelial cells but the application of VEGF was not successful in stimulating the more complex process of vasculogenesis.

Further immunohistochemical examinations of the specimen have shown that in the VEGF/PDLLA group there is strong immunostaining against matrix metalloproteinase 13 (MMP-13). In vitro studies have shown that VEGF can stimulate chondrocytes to proliferate but also to express MMP-13 via HIF1- induction. Since meniscal fibrochondrocytes express the VEGF receptor 2 (KDR) the induction of MMP expression might be another factor which inhibits healing despite increased angiogenesis.

In conclusion, the local application of VEGF via PDLLA-coated sutures does not promote meniscal healing. A single growth factor might not always be a promising tool for the promotion of tissue repair. Further studies have to find out if growth factor combinations (VEGF and angiopoitin) might be more effective in stimulating vasculogenesis during meniscal healing.     

Age-related changes in the glycosaminoglycans of human meniscal aggrecan

Introduction Meniscal damage and degradation, which are strongly correlated with subsequent OA, have been identified in approximately 60% of people over 60 years of age. Age‐related changes in articular cartilage glycosaminoglycans (GAGs) have been described, and used to facilitate the study of pathology‐related changes ( Plass et al. 1998 ). However, such data do not yet exist for the meniscus. Materials and methods Undamaged human menisci were obtained following leg amputations, and the vascular and avascular zones of each lateral and medial meniscus were extracted into 4 m GuHCl. Aggrecan was recovered in the A1 fraction following CsCl density gradient centrifugation, and the relative abundance of chondroitin, dermatan and keratan sulphates (CS, DS and KS) was examined by NMR spectroscopy at 400 MHz and 43 °C. Results Human meniscal aggrecan was shown to contain CS, DS and KS, and our data show age‐related changes in the relative abundance of these GAGs. The change was similar for medial and lateral menisci and for the vascular and avascular zones within these. The KS abundance in aggrecan from young menisci (<15 years) was found to be 15–20% of the total GAGs. However, in older samples, it comprised only 7–12% of the GAGs. We have confirmed the presence of DS in human meniscal aggrecan and show that the abundance of DS gradually falls from approximately 16% at 10 years to 2–4% at 75 years. There is some variability between humans, although the trend is clear and for each human there is good agreement between medial and lateral menisci and vascular and avascular locations. The levels of CS comprise the remainder of the GAG attached to aggrecan and contribute the remainder of the GAG abundance. This can be seen to increase from 67 to 72% at 10 years to approximately 90% at 75 years. Discussion Our data show a clear age‐related change in the relative abundance CS, DS and KS from human meniscal aggrecan. The data show a decrease in the abundance of KS and DS and a concomitant increase in CS levels. These observations differ from those widely seen for articular cartilage, in which the levels of CS are seen to fall with age. We have confirmed that DS is a component of human meniscal aggrecan in agreement with previous work ( McNicol & Roughley 1980 ). However, previously reported levels of DS, approximately 20%, are those found only in younger menisci. Absolute levels of these GAGs have not yet been determined, and hence the mechanisms which bring about this relative increase in CS with age may include either changes in biosynthetic output and/or widespread GAG loss in which KS and DS loss increases with age.     

Nutrition pathways to the symphysis pubis

The blood supply of the symphysis pubis is still the subject of some debate. Classic anatomy books state that this joint is avascular, whereas some published works have shown blood vessels in young specimens. As several articular discs such as the knee menisci are known to have blood vessels in their peripheries, we decided to investigate the possible nutrition pathways to the interpubic disc and ligaments. We used 60 Wistar rats, male and female, aged between 28 and 32 days, or between 90 and 100 days. Samples were processed using a variety of techniques: regular histology, immunohistochemestry, India ink injection and corrosion casting. The interpubic disc consisted of an inner bearing portion and an outer fibrous rim. The interpubic ligaments and the fibrous rim were well vascularized in all groups. Marrow contacts between the interpubic disc and the subchondral bone were also observed. Blood vessels formed an authentic arterial circle embracing the joint, from which blood vessels branched into capillary loops facing the avascular inner bearing portion of the disc. These results confirm the need for future studies on the human symphysis pubis, to provide more details on its structure, which would enable clinicians such as physiotherapists to improve prognosis and treatment design. Future studies may also explain the pathways down which the hormone relaxin reaches its targets within this joint.     

In vitro healing of avascular meniscal injuries with fresh and frozen plugs treated with TGF-beta1 and IGF-1 in sheep

We studied the effect of freezing and inserting meniscal plugs in lesions generated in the avascular area of sheep menisci maintained in vitro, and whether the healing process can be improved by adding growth factors TGF-beta1 and IGF-1. Thirty six menisci obtained from healthy 3 months-old sheep were cultured in 6 well plates and holes were perforated in the avascular area. Meniscal plugs, either fresh or frozen at -20 degrees C for 1 month, were used to fill in the lesions, and then cultured in the presence or absence of TGF-beta1 or IGF-1 for 8 weeks. Samples stained with Massons trichrome were analyzed to evaluate the attachment of the plug and the cell density of the tissue. BrdU immunohistochemistry was performed to identify the proliferation of meniscal cells. Both growth factors improved considerably the cell density of implanted plugs. TGF-beta1 increased significantly the attachment of both fresh and frozen plugs, but it had no effect on meniscal cell proliferation. In contrast, IGF-1 had no effect on the attachment, but did increase significantly the number of proliferating cells in the surface of the host meniscus and the inserted plug. In conclusion, frozen plugs can survive if treated with either TGF-beta1 or IGF-1. The combination of TGF-beta1 and IGF-1 could aid in the repairing of the avascular meniscal injuries, as they are capable of promoting the attachment of tissue, and increasing the proliferation of meniscal cells.     

Kinetic study of the replacement of porcine small intestinal submucosa grafts and the regeneration of meniscal-like tissue in large avascular meniscal defects in dogs.

Porcine small intestinal submucosa (SIS) was used to replace large, avascular defects in the medial menisci of dogs. Twelve dogs received SIS grafts and 3 dogs were left untreated as controls. Dogs were evaluated at 4, 8, and 12 weeks by means of lameness scoring and ultrasonography. Dogs were sacrificed at 1, 6, or 12 weeks after implantation, and the tissue at the site of meniscal resection was evaluated for gross and histologic appearance, cross-sectional and surface area, and collagen types I and II. The femoral and tibial condyles were assessed for articular cartilage damage. Control dogs were significantly more lame than grafted dogs 8 and 12 weeks after instrumentation. Grafted dogs' replacement tissue appeared meniscal-like when evaluated grossly and ultrasonographically 12 weeks after instrumentation. The amount of replacement tissue was significantly greater in both cross-sectional and surface area for grafted dogs than for controls at all time points. Histologically, the SIS biomaterial could be identified in all grafted dogs at 1 week post-implantation, but in none at 6 weeks post-implantation. Subjectively, grafted dogs' replacement tissue was histologically superior to that of controls with respect to tissue type, organization, and architecture. Collagen types I and II immunoreactivity in grafted menisci were similar to that of normal menisci. Control dogs had significantly more articular cartilage damage than grafted dogs. SIS appears to induce regeneration of meniscal-like tissue in large, avascular meniscal defects in dogs, resulting in superior clinical function and articular cartilage protection compared to ungrafted controls.     

Photochemical tissue bonding using monomeric 4-amino-1,8-naphthalimides

Certain substituted naphthalimides have been shown to produce, on photochemical activation, mechanically viable bonds between a variety of tissue surfaces. It is believed that these compounds act as photochemically activated oxidants, catalyzing the formation of reactive intermediates in the extracellular matrices of approximated tissue surfaces. The condensation of these intermediates results in the formation of crosslinks between the intimate surfaces. Of particular interest is the application of this technique to the repair of tears in the typically unrepairable avascular zone of menisci. The menisci are collagen-rich fibrocartilaginous tissues that support up to 90% of the load across the knee joint and participate in important functions including shock absorption, joint stabilization, hyperextension prevention, and lubrication of the knee. Preliminary ex vivo and in vivo work in our laboratories has demonstrated that photochemically activated naphthalimides have significant potential for the repair of meniscal lesions. We describe preliminary ex vivo studies assessing the relative abilities of a variety of water-soluble monomeric 4-amino-1,8-naphthalimides to bond bovine knee meniscal tissue on visible light irradiation.     

C4d deposits mark sites of meniscal tissue disintegration

Although the frequent occurrence of meniscal degeneration is a well-known fact and its consequences include rupture and even loss of the meniscus, the pathogenetic factors are established insufficiently. Because complement factors and leukocytes are present in synovial fluid, we tried to detect complement deposits and macrophages in menisci, which displayed degenerative changes. We therefore performed a retrospective analysis by immunohistochemical staining of C4d and CD68 in meniscal tissue derived from patients (n=15) who underwent meniscectomy because of meniscal tears and from three autopsy cases (n=3). In this study, focal C4d deposits in the meniscal extracellular matrix in areas of mucoid degeneration or fibrillation were demonstrated for the first time, while no C4d deposits in the avascular zone of menisci without signs of degeneration or injury could be detected. In addition, colocalization of C4d and CD68+ cells was found at sites of meniscal tissue disintegration in five cases. These results represent the first evidence for an involvement of complement and macrophages in meniscal tissue disintegration, indicating a complement mediated reaction at the site of tissue alteration.