【作者】 张向鑫；

【导师】 肖现民； 马瑞雪； 陈莲； 马巍；

【作者基本信息】 复旦大学 ， 小儿外科学， 2008， 博士

【摘要】 [背景和目的]发育性髋关节发育不良(Developmental dysplasia of the hip,DDH)是小儿矫形外科最常见的疾病之一,常见类型包括髋臼发育不良及头臼包容异常。轻度髋关节发育不良导致成年后的骨性关节炎(Osteoarthritis,OA)的发病率很高,大多数必须进行全髋关节置换术(Total hip arthroplasty,THA),降低了生活质量。目前对于DDH的微循环改变和软骨病理形态学改变已有报道,并认为DDH早期发生了关节软骨退变,但对关节软骨的退变机制及相关大分子蛋白的表达、整合素的表达等力学生物学方面的研究尚未见报告。本研究旨在检测与关节软骨退变有关的胶原与基质金属蛋白酶(MMPs)等大分子蛋白、整合素力学信号传导系统在DDH早期髋臼软骨中的表达,探讨它们与DDH软骨退行性变化的相关性,研究软骨退变的机制,为临床DDH的早期治疗提供理论依据,为进一步深入研究DDH、DDH与骨性关节炎的关系提供新思路。[方法]一、DDH动物模型的制作及骨密度、病理组织学观察1.采用目前普遍认可的兔伸膝位固定制作DDH动物模型的方法,左下肢作为实验侧,右下肢不作任何处理作为对照侧,5周后X线证实建模成功16只。2.Norland/p-DEXA型骨密度分析仪采用双能X线技术测定髋臼骨矿含量进行骨密度检测观察软骨和骨性结构退变情况,SPSS 12.0统计和比较组间差异。3.髋臼软骨标本HE常规染色、甲苯胺蓝特殊染色后光镜下观察髋臼软骨细胞与细胞外基质的病理组织学改变。二、Ⅱ型胶原、基质金属蛋白酶-7(MMP-7)在DDH髋臼软骨中的表达1.第一部分DDH模型选用8只髋臼软骨标本。2.采用免疫组化染色定性检测Ⅱ型胶原、MMP-7在髋臼软骨中表达的改变。3.采用Western-blot免疫印迹定量检测Ⅱ型胶原蛋白、MMP-7蛋白在髋臼软骨中表达的改变,SPSS12.0统计和比较组间差异。三、整合素α5β1在DDH髋臼软骨中的表达1.DDH重新建模8只获取髋臼软骨标本进行整合素α5β1 mRNA的提取和逆转录。2.采用荧光实时定量PCR检测整合素α5β1 mRNA在髋臼软骨中表达量的改变。3.SPSS12.0统计和比较组间差异。[结果]一、DDH动物模型的制作及骨密度、病理组织学观察1.建模成功率76.2%(16/21)。2.骨密度结果显示实验组低于对照组,但统计分析组间差异无统计学意义(P＞0.05)。3.病理组织学可见到软骨退变征象:甲苯胺蓝染色有失染现象,少量软骨细胞簇聚现象。二、Ⅱ型胶原、基质金属蛋白酶-7(MMP-7)在DDH髋臼软骨中的表达1.实验组Ⅱ型胶原在软骨层ECM中不均匀表达,柱状细胞层明显,细胞周围出现环绕棕色深染,胞浆内明显棕色深染细胞数目较对照组多。Ⅱ型胶原蛋白表达量升高,与对照组比较差异有统计学意义(P＜0.05)。2.实验组软骨细胞胞浆内MMP-7阳性细胞数目较对照组明显增多。MMP-7蛋白表达量升高,与对照组比较差异有统计学意义(P＜0.05)。三、整合素α5β1在DDH髋臼软骨中的表达对照组有整合素α5β1mRNA的表达,实验组整合素α5β1的表达明显升高,统计分析组间比较差异有统计学意义(P＜0.05)。[结论]1.DDH早期髋臼软骨出现软骨退变病理改变,而同期髋臼骨密度降低但差异没有统计学意义。2.DDH早期与髋臼软骨退变有关的Ⅱ型胶原和MMP-7表达量增多;Ⅱ型胶原、MMP-7的数量和强度可能是软骨退变程度差异的基础;Ⅱ型胶原、MMP-7作为生物学指标反映关节软骨的退变程度需进一步研究论证。3.DDH早期髋臼软骨整合素α5β1表达增多;整合素α5β1可能在髋关节力学传导中发挥力学传感器的作用。4.DDH早期,整合素力学信号传导系统接受作用于髋臼软骨的机械应力并传导至细胞内,启动软骨退变,软骨细胞形态、细胞外基质成分发生改变,Ⅱ型胶原、MMP-7等合成增多,胶原又与整合素结合加速软骨退变进程。更多还原

【Abstract】 [Background and Objective]Developmental dysplasia of the hip(DDH) is one of the most common diseases in pediatric orthopedics.The commom types include acetabular dysplasia and abnormal relationship between the femoral head and acetabular bone.Mild DDH can cause a high morbility of osteoarthritis(OA) in adult,and most of the OA patients have to receive total hip arthroplasty(THA).The present studies have ensured the retrogressive changes of the acetabular cartilage in early period of DDH.But the mechanobiological studies about the retrogression mechanism of acetabular cartilage, the expression of giant molecule proteins correlated to retrogression and the expression of integrins haven’t been reported.The purpose of this study is to detect the changes of the expression of collagen,matrix metalloproteinase(MMPs) and integrins of acetabular cartilage in early DDH,to study the retrogression mechanism of the acetabular cartilage,to provide theoretical evidence for early treatment to DDH, to explore a new idea for further study of DDH.[Methods]PartⅠ.To establish animal model of DDH,detect bone mineral density(BMD), observe pathohistology.1.Apply the method of knee extending,in which left lower extremity as experimental group and right lower extremity as control group,to establish successfully 16 animal model of DDH by X-ray after 5 week’s cast immobilization.2.Apply the method of Dual Energy X-ray Absorptiometry(DEXA) by Norland/p-DEXA BMD analysator to detect the BMD of acetabular bone in both groups,analyze the results using SPSS 12.0.3.Using the staining of HE and Toluidine Blue to observe the changes of chondrocytes and extracellular matrix(ECM) of acetabular cartilage samples. PartⅡ.To detect the expression ofⅡtype collagen and matrix metalloproteinases-7 (MMP-7) in acetabular cartilage of DDH.Apply the technique of immunohistochemical staining and western-blot to respectively qualitate and quantitate the expression ofⅡtype collagen and MMP-7 of 8 cartilage samples from the partⅠ.Analyze the results using SPSS 12.0.PartⅢ.To detect the expression of interinα5β1 in acetabular cartilage of DDHWe established another 8 animal models of DDH to obtain the samples of acetabular cartilage.After the extraction and reverse transcription of mRNA of integrinα5β1,we used the fluorescent quantitation RT-PCR(FQ RT-PCR) to determine the changes of the DNA copy numbers.Analyze the results using SPSS 12.0.[Results]PartⅠ.To establish animal model of DDH,detect BMD,observe pathohistology.1.The achievement ratio of establishing animal model of DDH achieved 76.2%(16/21).2.The results of BMD in experimental group were lower than that of control group, but there was no significant difference between two groups(P＞0.05).3.Pathohistology observing indicated the signs of retrogressive changes of the acetabular cartilage,including loss stain of ECM in Toluidine Blue stain and cluster chondrocytes in HE stain.PartⅡ.To detect the expression ofⅡtype collagen and MMP-7 in acetabular cartilage of DDH1.Ⅱtype collagen expressed unevenly in the ECM of experimental group,especially in cylindric cell layer.The positive numbers of immunohistochemical staining were higher than that of control group.The quantitative detection by western-blot in experimental group was higher than that of control group.There was significant difference between two groups(P＜0.05).2.The positive numbers of MMP-7 intracytoplasm were higher than that of control group.The quantitative detection by western-blot in experimental group was higher than that of control group.There was significant difference between two groups(P＜0.05).PartⅢ.To detect the expression of interinα5β1 in acetabular cartilage of DDHThere was positive expression of interinα5β1 mRNA in both groups,but the DNA copy numbers in experimental group was obviously higher that of control group. There was significant difference between two groups(P＜0.05).[Conclusions]1.There were pathologic changes of retrogression in acetabular cartilage of early DDH.Meanwhile,the BMD of acetabular bone in experimental group was lower than that of control group.There was no significant difference between two groups.2.The expression ofⅡtype collagen and MMP-7 correlated to retrogression of acetabular cartilage increased obviously in early DDH.The amount and intensity ofⅡtype collagen and MMP-7 is probably the base of differential retrogression of cartilage.The possibility ofⅡtype collagen and MMP-7 as biological parameters to reflect the degree of retrogression need further studies.3.The expression of interinα5β1 of acetabular cartilage increased obviously in early DDH.Interinα5β1 probably play an important role of mechanics sensing transmitter in the signal transduction system of hip joint.4.The retrogression mechanism of acetabular cartilage during early period of DDH: First,the mechanics signal transduction system of interins responds to the mechanical stress on the acetabular cartilage and then transmits the signs into cytoskeleton;Second,the procedure of retrogression is switched on,the cell morphous and the composition of ECM begin to change;Final,the amount of the synthesis ofⅡtype collagen and MMP-7 increases obviously.Meanwhile,the combination of increased collagen with increased integrins accelerates the proceeding of retrogression again.更多还原