兔后交叉韧带断裂后外侧胫骨平台退变的组织学研究

目的：探讨兔后交叉韧带（Posterior cruciate ligament,PCL）断裂对外侧胫骨平台组织学的影响。方法：48只家兔膝关节随机配对为实验侧和对照侧造模,造模后第4、8、16、24周各随机处死12只,行外侧胫骨平台大体观察、HE染色、免疫组化检测基质金属蛋白酶13（matrix metalloproteinase-13,MMP-13）、基质金属蛋白酶抑制剂1（Tisse inhibitor-1 of matrix metalloproteinasel,TIMP-1）表达。结果：①大体观察,随时间延长,实验组外侧胫骨平台软骨出现磨损,呈灰黄色,弹性差,骨赘形成。②组织学观察,随时间延长,胫骨平台软骨纤维化,细胞排列紊乱,簇聚细胞出现频率增加。⑧实验组MMP-13、TIMP—1表达均高于对照组,有显著性差异。P〈0．05。④实验组MMP-13、TIMP-1表达阳性率第4、8、16周逐渐升高,24周下降,各组比较有显著性差异,P〈0．05。结论：①兔膝关节PCL断裂会引起外侧胫骨平台软骨退行性变,且该退变随着时间的推移逐渐加重。②MMP-13与TIMP-1在PCL断裂膝关节外侧胫骨平台中的表达呈现先高后低的变化规律,造成MMP-13与T1MP-1的失衡,加速软骨退变。⑨MMP-13与T／MP-1表达增高提示MMP-13与TIMP—1可能参与了PCL断裂后外侧胫骨平台软骨的退变过程。     

关节腔注射强力霉素对兔膝骨关节炎模型的影响

目的:研究关节腔内注射强力霉素对兔制动性骨关节炎模型的影响.方法:30只新西兰大白兔随机分成正常组6只及实验组24只,试验组左膝关节伸直位石膏固定4周随机选取6只处死左膝关节取材证实造模成功后剩余18只为左膝骨关节炎模型,随机分为治疗组、阴性对照组和模型对照组,治疗组每日给予1.33%的强力霉素0.3毫升左膝关节腔内注射,阴性对照组每日给予生理盐水0.3毫升左膝关节腔注射,模型对照组不做处理,于8周处死取材.观察指标包括关节软骨大体形态,软骨Mankin's评分,软骨细胞基质金属蛋白酶-3(MMP-3)表达及滑膜细胞白介素-1(IL-1)表达.结果:强力霉素治疗组软骨面退变明显轻于模型组及生理盐水对照组,软骨大体评分,Mankin评分,MMP-3表达及滑膜IL-1表达亦显著降低.结论:强力霉素关节腔内注射对兔制动性骨关节炎模型软骨退变有明显的缓解作用.     

羌活地黄汤对大鼠佐剂性关节炎软骨金属蛋白酶-1、13及基质金属蛋白酶抑制剂-1的影响

目的：观察羌活地黄汤对大鼠佐剂性关节炎软骨中基质金属蛋白酶-1（marxmetalloproteinase-1,MMP-1）、基质金属蛋白酶-13（matrixmetalloproteinase．13,MMP-13）及基质金属蛋白酶抑制剂-1（tissueinhibitorofmetalloprotease-1,TIMP-1）表达的影响。方法：Wistar大鼠32只,随机分为正常对照组、模型组、雷公藤对照组、羌活地黄汤组。制作大鼠佐剂性关节炎模型,造模第14天开始给药。羌活地黄汤组予混有羌活地黄汤的颗粒饲料,雷公藤组给予混有雷公藤多甙的饲料,正常组及模型组均给予普通饲料。第28天分别取各组胫骨平台关节软骨,采用免疫组织化学染色测定软骨中MMP-1、13及T1MP—1表达的阳性指数。结果：模型组MMP-1、MMP-13及TIMP—1表达的阳性指数水平明显高于正常组,差异有统计学意义（P〈0．01）,羌活地黄汤组MMP-1、13及TIMP-1表达阳性指数低于模型组,差异有统计学意义（P〈0．05）。结论：羌活地黄汤可能是通过调控软骨细胞外基质中MMP．1、MMP—13及TIMP-1表达变化而维持软骨的动态平衡,从而延缓RA骨骼破坏。     

T140阻断SDF-1/CXCR4信号通路并在骨关节炎疾病模型中防止软骨退化

为了探讨T140通过靶向阻断SDF-1/CXCR4信号通路调节体内关节软骨退变的作用,并为以后的临床研究提供一定的参考,将45只健康的Hartley豚鼠随机分成3组,分别为:T140处理组(n=15)、磷酸盐缓冲盐水对照组(n=15)和未处理对照组(n=15)。分别在处理的2周、6周、8周、10周和12周,通过酶联免疫吸附测定法定量血清中的SDF-1。在治疗12周时,收集膝关节胫骨的软骨用于HE和番红-O染色同时进行Mankin分级;使用RT-PCR测量基质金属蛋白酶(MMP-3, MMP-9和MMP-13),聚集蛋白聚糖(ACAN)和胶原蛋白Ⅱ(ColⅡ)的m RNA表达水平;通过蛋白质印迹测量ColⅡ蛋白的表达水平。T140组中的SDF-1含量升高。与对照相比,HE和番红-O染色显示T140处理的动物中的软骨损失较少。T140组软骨中MMP-3、MMP-9和MMP-13的mRNA表达水平明显低于其他组。而T140处理组软骨中ACAN和ColⅡ的mRNA表达水平明显升高,T140组和对照组中的ColⅡ蛋白水平各不相同。T140可以通过在体内阻断SDF-1/CRCR4信号传导途径来下调基质金属酶的表达水平并减轻软骨的变性,为治疗OA的药理学提供了靶标。     

基质金属蛋白酶及其抑制剂在乳腺癌中的表达

目的:研究基质金属蛋白酶2(Matrix Metalloproteinase-2,MMP-2),基质金属蛋白酶7(MMP-7),基质金属蛋白酶9(MMP-9),膜型基质金属蛋白酶(Membrane Type-1 Matrix Metalloproteinase,MT1-MMP),金属蛋白酶组织抑制剂1(Tissue Inhibitor of Metalloproteinase,TIMP-1),金属蛋白酶组织抑制剂2(TIMP-2)在乳腺癌组织中mRNA的表达,及与临床病理变量之间的关联。方法:采用150例乳腺癌患者的组织样本。使用半定量逆转录-聚合酶链反应(RT-PCR)法来测定肿瘤组织和正常乳腺组织中MMP-2,MMP-7,MMP-9,MT1-MMP,TIMP-1和TIMP-2的mRNA表达。结果:MMP-2,MMP-7,MMP-9,MT1-MMP,TIMP-1和TIMP-2在乳腺癌中的mRNA表达显著高于正常组织。结论:MMP-2,MMP-7,MMP-9,和MTI-MMP的表达增加和临床病理参数之间的关联,可以用来预测乳腺癌的侵害行为。     

丹参单体IH764-3通过下调H2O2刺激的肝星状细胞FAK水平影响MMP-13和TIMP-1的表达

目的：研究丹参单体IH764—3对H2O2刺激的肝星状细胞（HSC）基质金属蛋白酶-13（MMP-13）、基质金属蛋白酶组织抑制因子-1（TIMP-1）表达的影响以及此过程中粘着斑激酶（FAK）的变化。方法：应用RT-PCR方法检测MMP-13及FAKmRNA表达,原位杂交方法检测TIMP-1mRNA水平,Western blotting技术检测FAK及TIMP-1蛋白表达。结果：IH764—3干预组的MMP-13mRNA在2h的表达强度明显上调,而TIMP-1mRNA表达明显受抑,FAKmRNA表达强度明显下调;IH764—3干预24h组FAK及TIMP-1蛋白表达受抑制。结论：丹参单体IH764—3可以诱导MMP-13表达,抑制TIMP-1表达,下调FAK表达是其中的机制之一。     

己酮可可碱对肺纤维化大鼠MMP-2和TIMP-1表达的影响

目的观察己酮可可碱(pentoxifylline, PTX)对博来霉素致肺纤维化大鼠肺组织基质金属蛋白酶2(matrix metalloproteinase-2)和基质金属蛋白酶组织抑制剂1(tissue inhibitor of matrix metalloproteinase-1)表达的影响,初步探讨其抗肺纤维化的作用机制.方法 SD大鼠36只,随机分为模型组、治疗组和对照组.模型组和治疗组气管内注射博来霉素诱导肺纤维化,对照组在相同条件下给予生理盐水.第二天起治疗组大鼠腹腔给予己酮可可碱6mg/kg.d,其余两组相同条件下给予生理盐水.治疗的第7d和28d,处死动物取出肺组织,用RT-PCR和免疫组化ABC法观察各组鼠肺组织MMP-2和TIMP-1表达的变化. 结果与模型组比较,治疗组经PTX作用的第7d和28d肺组织中MMP-2和TIMP-1 mRNA的基因转录均有减少,MMP-2 mRNA表达分别降低33.4%和35.5%(P＜0.001),TIMP-1 mRNA表达分别降低25.3%和33.0%(P＜0.05).免疫组化结果则显示,PTX作用的第7d和28dMMP-2分别较模型组降低30.7%和41.7%(P＜0.05),TIMP-1分别降低13.1%和19.8%(P＜0.05).结论 PTX对肺纤维化不同时期肺组织中MMP-2和TIMP-1的表达均有一定程度的降低作用,其可能通过调整MMP-2和TIMP-1比值使其趋于平衡,从而延缓甚至抑制纤维化的进程.     

机械性去负荷后心室明胶酶及其组织型抑制剂与细胞外基质变化

目的：探讨左心室在去除压力和容量负荷下心室组织基质金属蛋白酶-2和-9及金属蛋白酶组织型抑制剂-1和-2表达水平与细胞外基质沉积量的关系。方法：12周龄雄性Lewis大鼠建立Lewis-to-Lewis腹腔异位心脏移植模型,形成左心室去负荷状态,并以同龄雄性Lewis大鼠胸腔原位心脏作为对照。移植后14d采用天狼猩红-偏振光法对移植和对照组心脏的ECM沉积量进行分析。心室组织MMP-2和MMP-9活性检测采用明胶酶谱法。MMP-2、MMP-9、TIMP-1、TIMP-2的mRNA表达水平检测采用荧光定量PCR法;TIMP-1和TIMP-2蛋白含量采用Western blot测定。结果：手术后14d,与原位心脏比较,腹腔移植心脏心肌细胞横截面积减小,并伴有心肌ECM沉积量增多（胶原容积分数5．22％±1．6％VS2．21％±0．9％,P〈0．05）,并且MMP-2、MMP-9明胶酶活性明显增强,MMP-2、MMP-9及其组织型抑制剂T1MP-1、TIMP-2的mRNA表达均增加（P〈0．05）,但TIMP-1、TIMP-2增加幅度较MMP-2、MMP-9高,TIMP-1、TIMP-2的蛋白含量均增加（P〈0．05）,TIMP-1增加幅度更为明显。结论：左心室在去除压力和容量负荷状态下心脏心室组织胶原沉积量增加,伴有MMPs／TIMPs系统失衡,尤其是TIMPs系统的明显上调。     

外源性uPA对兔椎间盘作用的初步研究

目的：通过不同浓度外源性尿激酶型纤溶酶原激活剂（uPA）兔椎间盘内注射,探讨uPA对椎间盘作用。方法：健康大白兔72只,随机分为实验组48只,阴性对照组16只,空白对照组8只。实验组：分为三个亚组,L4／5椎间盘内分别注射浓度为10、20、40ng／μl的uPA各1μl。阴性对照组：椎间盘内注射1μl的生理盐水。空白对照组：不作任何处理。分别于第3、6周取相应椎间盘,大体观察、HE染色、SABC法测基质金属蛋白酶-3（MMP-3）的表达及蛋白多糖含量测定。结果：实验组MMP．3表达显著增强,蛋白多糖含量明显降低,与同期对照组比较（P〈0．05）,有显著统计学意义。实验组在不同时间及不同浓度比较也有统计学意义。结论：外源性uPA能够导致兔椎间盘内蛋白多糖含量降低,MMP-3表达显著增强,可能在椎间盘退变过程中其重要作用。     

慢性肾小球肾炎患者血清MMP-9和TIMP-1的浓度及意义

目的:观察慢性肾小球肾炎血清基质金属蛋白酶9(matrix metalo protein-ase-9,MMP-9)、金属蛋白酶组织抑制剂1(tissue inhibitors of metalloproteinases,TIMP-1)的浓度与肾组织中MMP-9、TIMP-1表达的相关性,探讨慢性肾小球肾炎血清MMP-9、TIMP-1对肾脏纤维化的判断价值。方法:通过肾组织活检病理检查,将入选慢性肾炎的病例分增生组(A组)15例,纤维化组(B组)15例,另选10例志愿者作为健康对照组C组。应用免疫组化法观察A、B两组MMP-9、TIMP-1在肾组织中的表达情况,并且进行半定量分析,比较它们之间有无差别。应用ELISA双抗体夹心法检测A、B、C三组MMP-9、TIMP-1在血清中的浓度,比较它们之间有无差别。观察A、B两组MMP-9、TIMP-1在肾组织中的表达水平与在血清的浓度有无相关性。结果:A、B两组MMP-9在肾小球和肾间质少见表达,主要在肾小管上皮细胞浆中表达增高,两组之间表达的强度有显著差异性;A组TIMP-1在肾小球中少见表达,在肾小管上皮细胞增强。B组TIMP-1在肾小球中有少量表达,在肾小管上皮细胞较A组进一步增强,两组之间表达的强度有显著差异性(P0.05)。血清中MMP-9、TIMP-1浓度在A、B组显著高于C组,血清中MMP-9在A、B两组之间无显著差异性,血清中TIMP-1在A、B、C三组间两两比较有显著差别(P0.05)。结论:慢性肾炎患者血清中MMP-9、TIMP-1浓度与肾脏组织中MMP-9、TIMP-1的表达呈正相关。MMP-9、TIMP-1的相关性分析P值小于0.01。血清MMP-9、TIMP-1参与了肾脏纤维化的进展,慢性肾小球肾炎血清中MMP-9、TIMP-1的浓度可在一定程度上反映肾脏纤维化程度。     

Chronic changes in the rabbit tibial plateau following blunt trauma to the tibiofemoral joint

The knee is often a site of injury that can often lead to a chronic disease known as osteoarthritis (OA). The disease may be initiated, in part, by acute injuries to joint cartilage and its cells. In a recent study by this laboratory, using Flemish Giant rabbits, an impact compressive load on the tibial femoral joint was shown to cause significant levels of acute damage to chondrocytes in cartilage of the medial and lateral tibial plateaus. In the current study, using the same model, histological and mechanical data from the plateaus were documented at 6 and 12 months post impact, and compared to the unimpacted control limbs and a limb from unimpacted, control animals. The mechanical properties of cartilage were measured with indentation relaxation tests on the medial and lateral plateaus in regions covered and uncovered by the meniscus. The histological studies on impacted limbs showed surface lesions on both plateaus, thickening of the underlying subchondral bone at 12 months and numerous occult microcracks at the calcified cartilage–subchondral bone interface at 6 and 12 months, without significant changes in cartilage thickness or its mechanical properties versus controls. Yet, there was an increase in both the matrix and fiber moduli and a decrease in the permeability of uncovered, medial plateau cartilage in both limbs of impacted animals between 6 and 12 months post impact that was not documented in control animals.     

膜性高分子材料在兔眼部的生物相容性

目的评价聚羟基脂肪酸(polyhydroxyalkanoates,PHA)、聚乳酸(polylacetic acid,PLA)和聚己内酯(polycaprolactone,PCL)三种膜性高分子材料在兔眼部的生物相容性。方法将24只新西兰兔随机分为4组,每组6只。PHA、PLA、PCL为实验组,材料植入兔右眼结膜下。假手术组结膜下钝性分离,但不植入任何高分子材料。使用裂隙灯显微镜观察并记录植入后不同时间手术眼的反应并评分。裂隙灯下观察材料的吸收时间。术后4周和16周取眼球,行HE染色、Masson染色和天狼猩红染色分别定性观察组织结构和炎症细胞、胶原纤维和胶原纤维的亚型与排列方向。结果术眼刺激性评分等级各组均不高于"轻度刺激性"。结膜下吸收时间PHA、PLA和PCL组分别是16周,12周和大于16周。组织学观察术后4周PHA、PLA和PCL组均形成材料包裹囊腔,囊壁以纤维组织为主,伴有毛细血管形成和炎性细胞浸润,以中性粒细胞为主。胶原纤维染色与假手术组无明显差异,以Ⅰ型和Ⅲ型为主,大致呈平行排列。术后16周PHA和PLA组材料已不可查及,包裹囊腔结构不规则,而PCL材料整体可查及,包裹囊腔规则。各组未见毛细血管,偶见淋巴细胞浸润。胶原纤维与假手术组无明显差异,以Ⅰ型和Ⅲ型为主,仍大致呈平行排列。结论 PHA、PLA和PCL三种膜性高分子材料在兔眼具有较好的生物相容性,结膜下吸收时间分别是16周,12周和大于16周。     

糖尿病对大鼠骨折愈合影响的实验研究

目的:观察糖尿病大鼠的骨折愈合过程,探讨糖尿病影响大鼠骨折愈合的可能的机制,为临床实践提供理论依据。方法:雄性Wister大鼠140只,随机分成二组,每组70只,A组为糖尿病骨折组;B组为非糖尿病骨折组。建立糖尿病动物模型后,无菌条件下在各组大鼠胫骨中点用手术方法制成骨折模型。术后1周、2周、4周、6周、8周各时间点进行X线检查,观察骨折愈合情况。术后1周、2周、3周、4周、6周、8周分别用ELISA法检测血清中IGF-1含量。分别在1、2、4、6、8周各时间点观察5只大鼠骨痂生长情况并取骨折断端组织行HE染色光镜观察。术后4周、6周、8周每组处死10只大鼠留取双侧胫骨标本,冷冻保存后集中进行生物力学检测。结果:1、大体标本观察结果:各时间点A组骨痂生长减缓延迟。2、X线结果:A组骨折愈合质量在各时间点均明显低于B组。3、生物力学测定结果:4周、6周、8周个时间点A组骨折处骨痂的机械强度均明显低于B组。4、组织学染色显示:术后各时间点1、2、4、6、8周A组与B组相比骨折处局部骨痂成熟延迟并且软骨细胞肥大。5、血清IGF-1含量测定:A组大鼠血清中IGF-1含量低于B组,且高峰延迟1周。结论:1.患有糖尿病后大鼠骨折愈合质量差,比较容易出现愈合延迟甚至不愈合;2.患有糖尿病的大鼠骨折后血清中的IGF-1表达明显低于对照组,且高峰推迟1周。     

A case-control study of anterior cruciate ligament volume,tibial plateau slopes and intercondylar notch dimensions in ACL-injured knees

The role played by anatomical factors in ACL injury remains elusive. In this study, objective methods were used to characterize ACL volume, tibial slopes and notch geometry from ACL-injured and matched-control subjects. The study tested four hypotheses: (1) the medial tibial plateau slope is steeper posteriorly in the injured group compared to the non-injured group, (2) the lateral tibial plateau slope is steeper posteriorly in the injured group compared to the non-injured group, (3) the femoral intercondylar notch dimensions are smaller in the injured group compared to the non-injured group and (4) the ACL volume, tibial plateau slopes and intercondylar notch dimensions are all independent of each other. Fifty-four subjects were divided into two groups, those who had suffered a non-contact ACL injury and those who still had two healthy ACLs, matched to the injured subjects by gender, age, height and weight. The lateral tibial plateaus in the uninjured contralateral knees of the injured subjects had a significantly steeper posterior slope (1.8° vs. ?0.3°), a factor that potentially contributed to the ACL injury in the opposite knee. The intercondylar notch dimensions were found to be smaller in the injured subjects, potentially putting the ACL at risk of impingement, and intercondylar notch volume was correlated to ACL volume (r=0.58). Discriminant analysis showed that the notch width at the inlet was the best single predictor of ACL injury.     

Dynamic contact stress patterns on the tibial plateaus during simulated gait: A novel application of normalized cross correlation

The spatial distribution and pattern of local contact stresses within the knee joint during activities of daily living have not been fully investigated. The objective of this study was to determine if common contact stress patterns exist on the tibial plateaus of human knees during simulated gait. To test this hypothesis, we developed a novel normalized cross-correlation (NCC) algorithm and applied it to the contact stresses on the tibial plateaus of 12 human cadaveric knees subjected to multi-directional loads mimicking gait. The contact stress profiles at different locations on the tibial plateaus were compared, where regions with similar contact stress patterns were identified across specimens. Three consistent regional patterns were found, among them two most prominent contact stress patterns were shared by 9–12 of all the knees and the third pattern was shared by 6–8 knees. The first pattern was located at the posterior aspect of the medial tibial plateau and had a single peak stress that occurred during the early stance phase. The second pattern was located at the central-posterior aspects of the lateral plateau and consisted of two peak stresses coincident with the timing of peak axial force at early and late stance. The third pattern was found on the anterior aspect of cartilage-to-cartilage contact region on the medial plateau consisted of double peak stresses. The differences in the location and profile of the contact stress patterns suggest that the medial and lateral menisci function to carry load at different points in the gait cycle: with the posterior aspect of the medial meniscus consistently distributing load only during the early phase of stance, and the posterior aspect of the lateral meniscus consistently distributing load during both the early and late phases of stance. This novel approach can help identify abnormalities in knee contact mechanics and provide a better understanding of the mechanical pathways leading to post-traumatic osteoarthritis.     

咪喹莫特调节Th1、Th2细胞相关趋化因子表达抑制兔耳瘢痕增生

目的:免疫因素在增生性瘢痕的发生中起重要作用,本实验研究免疫抑制剂咪喹莫特对兔耳增生性瘢痕组织中辅助性T淋巴(Th)细胞亚群Th1、Th2细胞相关趋化因子CXCL10、CXCL12、CCL2、CCL3、CCL5、CCL7、CCL13表达的影响,探讨咪喹莫特抑制兔耳瘢痕增生的作用机制。方法:选取16只新西兰大耳白兔,雌雄不限。建立兔耳增生性瘢痕模型,每只兔耳腹侧做四个直径为1 cm的圆形创面,每个相距1.5 cm,双侧对称,右耳为咪喹莫特组涂抹5%咪喹莫特软膏,左耳为空白对照组涂抹等量凡士林软膏,待术后14天上皮化均完全后开始涂抹,一日一次,持续一个月。分别于术后第21、28、35、42、49、56、63天同一时间空气栓塞法随机处死2只兔子,收集所有瘢痕标本。另外处死2只健康兔并采集兔耳正常皮肤组织。所有标本行HE染色及Masson三色法染色,观察形态学差异;测量并计算瘢痕增生指数(Scar elevation index,SEI);行Real-time PCR检测CXCL10、CXCL12、CCL2、CCL3、CCL5、CCL7、CCL13的表达。结果:HE及Masson染色可见咪喹莫特组胶原沉积较空白对照组明显减少,SEI显示空白对照组于术后第28天增生程度达到高峰,其增生程度明显高于咪喹莫特组(P0.05);Real-time PCR结果可见咪喹莫特组Th2细胞相关趋化因子CCL2、CCL3、CCL5、CCL7及CCL13表达在各时间点较空白对照组明显降低,Th1细胞相关趋化因子CXCL10、CXCL12的表达在各时间点较空白对照组明显增高(P0.05)。结论:咪喹莫特可通过调节Th1、Th2细胞相关趋化因子的表达来发挥抑制兔耳瘢痕增生的作用。     

珍珠明目液消炎作用观察

目的观察珍珠明目液对眼结膜刺激性及其对实验性兔眼部炎症的影响.方法给兔眼眶内滴入珍珠明目液(每次0.1ml/眼,1天3次,连续7天),观察给药7天后角膜、虹膜及结膜的反应;用30%巴豆油造成兔眼结膜炎,致炎前及致炎后局部应用珍珠明目液滴眼(0.1ml/眼),并设醋酸可的松眼药水治疗组和生理盐水对照组.于致炎后2、4、12、24、36、48及72h,根据结膜炎充血、水肿及分泌物轻重程度进行评分.结果珍珠明目液对兔眼角膜、虹膜及结膜未见明显异常反应.珍珠明目液治疗30%巴豆油所致兔眼炎症评分值显著低于相应生理盐水组(P＜0.01),与醋酸可的松治疗组比较无显著性差异.结论珍珠明目液无眼刺激性,对巴豆油致兔眼结膜炎具有较好的消炎作用.     

骨骼肌损伤修复的生理生化机制研究

为探讨新西兰兔股四头肌损伤修复过程中,按摩对骨骼肌和运动终板(MEP)损伤修复的生理生化机制,将30只雄性新西兰大白兔随机分成正常组、自然恢复组(损伤后7d(3只)、14 d和21 d三个亚组(各6只))和按摩治疗组(按摩7d和14d两个亚组(各6只)).重物打击法制作兔股四头肌急性损伤模型,H&E染色,AchE酶组化...     

The Effect of Graft Strength on Knee Laxity and Graft In-Situ Forces after Posterior Cruciate Ligament Reconstruction

Surgical reconstruction is generally recommended for posterior cruciate ligament (PCL) injuries; however, the use of grafts is still a controversial problem. In this study, a three-dimensional finite element model of the human tibiofemoral joint with articular cartilage layers, menisci, and four main ligaments was constructed to investigate the effects of graft strengths on knee kinematics and in-situ forces of PCL grafts. Nine different graft strengths with stiffness ranging from 0% (PCL rupture) to 200%, in increments of 25%, of an intact PCL’s strength were used to simulate the PCL reconstruction. A 100 N posterior tibial drawer load was applied to the knee joint at full extension. Results revealed that the maximum posterior translation of the PCL rupture model (0% stiffness) was 6.77 mm in the medial compartment, which resulted in tibial internal rotation of about 3.01°. After PCL reconstruction with any graft strength, the laxity of the medial tibial compartment was noticeably improved. Tibial translation and rotation were similar to the intact knee after PCL reconstruction with graft strengths ranging from 75% to 125% of an intact PCL. When the graft’s strength surpassed 150%, the medial tibia moved forward and external tibial rotation greatly increased. The in-situ forces generated in the PCL grafts ranged from 13.15 N to 75.82 N, depending on the stiffness. In conclusion, the strength of PCL grafts have has a noticeable effect on anterior-posterior translation of the medial tibial compartment and its in-situ force. Similar kinematic response may happen in the models when the PCL graft’s strength lies between 75% and 125% of an intact PCL.