渐进性咬合紊乱对大鼠髁突软骨中骨形成蛋白2表达的影响

目的：探讨渐进性咬合紊乱所致大鼠髁突软骨改建中骨形成蛋白2（BMP-2）的变化情况及其意义。方法：建立幼年和成年大鼠渐进性咬合紊乱模型,应用免疫组化SABC法检测大鼠髁突软骨中BMP-2的表达变化,并作图像分析和统计学处理。结果：幼年和成年实验组大鼠左右侧髁突软骨中BMP-2的表达差异无统计学意义。与对照组相比,幼年和成年实验组中BMP-2的表达于实验4周时均低于对照组（P〈0.01）,之后出现回升,8周时两组均高于对照组（P〈0.05）。不同时间点比较,幼年与成年实验组中BMP-2的表达在2~8周的时间内均出现先降低再增高的趋势。结论：BMP-2参与了髁突软骨随咬合变化而发生的改建活动。     

髁状突软骨纤维组织的超微结构观察

目的：深入了解髁突内部纤维组织的结构、走行方向、相互间关系及功能。方法：用扫描电镜和透射电镜观察了8例(16侧)家兔，体重为1．5—2．0kg，月龄6个月(动物由同济医学院中心实验室提供)。颞下颌关节髁状突剖面和切削面的超微结构。结果：在扫描电镜下，剖面呈现纵横交错的立体网状结构或者类似海绵状结构；切削处可见浅层的纤细网状纤维，这种纤维与泥土样物混合交织形成软骨的外层；在网状纤维的深层可见三种粗大的纤维平行于髁状突表面走行，其直径分别约为20nm、35nm和100nm。不同部位的纤维的排列、走向不尽相同。透射电镜下，髁状突内部纤维主要是有明显周期性横纹的I型胶原。结论：①髁状突表层存在一层纤细的网状纤维。②深层纵横交错的纤维呈海绵状结构具有传导和分散压力的作用。③纤维的粗细不同可吸收各种振动频率的力，形成了对作用于颞下颌关节各种力的有效缓冲垫。④透射电镜下纤维属I型胶原，说明髁状突软骨属纤维软骨。     

功能性矫治器引导下颌后退对大鼠髁突软骨新骨形成影响的实验研究

目的探讨功能性矫治器引导下颌后退所致的髁突软骨新骨形成的影响。方法选用4周龄SD雄性大鼠45只,分为实验组及对照组,每组5只。实验组模拟临床功能性矫治器引导大鼠下颌后退。分别在0、3、7、14及21 d全麻下处死动物各5只。苏木精-伊红染色观察细胞形态反应,PAS染色观察新骨形成量。结果大鼠在下颌持续后退情况下,实验组髁突后份软骨组织增殖层和成熟层明显变薄,移行区可见破骨细胞增加,此区附近的骨小梁骨沉积减少;实验第3天及第7天,实验组和对照组髁突软骨新骨形成的量有明显区别,第14天和第21天,二者间的差别趋于减小。结论后退大鼠下颌后,髁突软骨后份新骨形成量减少。     

咬合紊乱与去除咬合紊乱对大鼠髁突软骨中骨形成蛋白-2表达的影响

目的探讨咬合紊乱与去除咬合紊乱大鼠髁突软骨内骨形成蛋白- 2（BMP- 2）的变化。方法幼年和成年雌性大鼠各9只,等分为咬合紊乱组、去除咬合紊乱组和对照组。咬合紊乱组在建立咬合紊乱8周后处死,去除咬合紊乱组在建立咬合紊乱6周时拔除造成紊乱的双侧第一磨牙,2周后处死。对照组不作任何处理,同环境饲养、同期处死。测量各组髁突组织切片上软骨前、中、后部的厚度,SABC法检测软骨前、中、后部BMP- 2的表达。结果成年咬合紊乱组髁突软骨中部变薄,后部增厚;去除咬合紊乱后后部恢复正常,中部仍薄于对照组（P<0.05）。幼年髁突软骨的前、中、后部厚度三组间未见显著性差异（P>0.05）。幼年髁突软骨前、中、后部咬合紊乱组BMP-2表达高于去除咬合紊乱组和对照组（P<0.05）,成年髁突软骨中部咬合紊乱组和去除咬合紊乱组均高于对照组（P<0.05）,后部咬合紊乱组高于和去除咬合紊乱组,后者高于对照组（P<0.05）,前部无差异。结论咬合紊乱可导致幼年和成年大鼠髁突软骨BMP- 2高表达,成年大鼠髁突软骨对咬合紊乱的适应能力较幼年大鼠差,中部尤为明显。     

不对称性颌间牵引对成年SD大鼠颞下颌关节软骨下骨组织形态的影响

目的 通过观察不对称牵引引起的成年SD大鼠髁突软骨下骨组织形态学变化,了解关节外不对称机械应力对髁突软骨下骨的影响.方法 选用10周龄雄性SD大鼠220只（随机分为轻力组104只、重力组104只、对照组12只）,实验组动物使用关节外固定加力装置,分别施加0.39、1.18 N,加力28 d拆除加力装置.在3、7、14、28、31、35、42、56 d取得标本,对髁突软骨的形态、骨小梁密度进行观察分析并进行统计学处理.结果 正常髁突软骨下骨骨小梁连续,与髁突表面垂直以顺应髁突的力学环境,在负荷加载后出现骨小梁形态和排列变化,密度发生相应波动.结论 髁突软骨下骨在外力刺激下,出现排列和骨小梁密度的变化以适应变化的机械应力环境.     

升高咬合对青春期大鼠髁突软骨BMP-2表达变化的影响

目的 观察升高咬合后髁状突软骨骨形成蛋白-2(BMP-2)的表达。方法 40只5周龄雄性SD大鼠,随机分为4组对照组和4组实验组(双侧后牙板升高咬合)。实验组与对照组动物分别在第7、14、21及28天时处死。取其右侧髁突,采用SABC免疫组化方法观察髁突软骨细胞BMP-2阳性细胞的分布及含量改变。结果 与对照组相比,实验组髁突软骨细胞BMP-2阳性细胞表达在实验第7、14天明显减少,第28天明显增多(P<0.05)。结论 咬合升高后引起髁突软骨BMP-2高表达,髁突软骨发生适应性改建。     

兔下颌持续前导后髁突软骨中核心结合因子α1的表达及意义

目的:探讨兔下颌持续功能前导后髁突软骨中核心结合因子α1(corebindingfactorα1,Cbfα1)蛋白的表达及与髁突改建的关系。方法:60只8周龄日本大耳白兔,随机分为实验组和对照组,实验组动物每天24h戴用咬合前导矫正器。实验组与对照组动物分别在3天、1周、2周、4周、8周及12周时处死并取材,用免疫组化方法检测髁突组织内Cbfα1的分布和表达变化,并对其表达进行灰度测定,采用t检验和单因素方差分析对灰度值进行统计学分析。结果:Cbfα1主要在髁突软骨过渡层和肥大层软骨细胞的胞核和胞质中表达,钙化层的软骨细胞和成骨细胞中也可见Cbfα1的表达。实验组兔髁突软骨各层Cbfα1的表达强度均显著高于同期对照组(P<0.05),其中治疗后4周过渡层、肥大层和钙化层的表达均最为明显,分别是71.00±1.52,50.00±0.75和82.00±0.39。结论:下颌持续前导后,Cbfα1的动态变化与下颌髁突适应性生长改建关系密切。     

甲状旁腺激素相关蛋白调控下颌髁突软骨的研究进展

下颌髁突软骨(MCC)不同于生长板和身体其他部位的关节软骨,属于继发性纤维软骨,是颞下颌关节的重要组成部分.由于下颌骨附有牙齿行使咀嚼功能的特殊性,MCC在一生中受机械刺激影响不断改建,随年龄增长可能发生退行性变.甲状旁腺激素相关蛋白(PTHrP)最早在恶性体液性高钙血症中发现,在许多组织中以旁分泌或者自分泌的方式发挥...     

下颌前伸对成年大鼠髁突软骨Ⅹ型胶原表达的影响

目的:建立年轻成年大鼠下颌前伸动物模型,以X型胶原为检测指标,观察髁突软骨内成骨及其与下颌前伸持续时间的关系.方法: 9 周龄雌性大鼠75 只,分为3 组,其中2 组为实验组,另一组为对照组,实验组动物戴用统一规格自制的咬合前导矫治器,分别戴用12 h和24 h.3 组动物分别在实验后3、7、14、21、30 d处死后取双侧髁突组织,使用免疫组化和原位杂交方法从蛋白水平和基因水平检测髁突软骨组织切片中X型胶原的表达情况.结果:免疫组化结果显示, 24 h实验组X型胶原表达量在21 d时最高,且高于其他实验组;而12 h实验组峰值出现在30 d.原位杂交结果与免疫组化结果基本吻合.结论:功能矫治下颌前伸均能诱导年轻成年大鼠髁突软骨发生改建,但与12 h间歇性加力方式相比,24 h持续加力方式作用效果明显,且见效快.     

导下颌向前对生长期大鼠髁突软骨结缔组织生长因子表达的影响

目的:通过建立导下颌向前的Sprague-Dawley (SD)大鼠的动物模型进行免疫组化实验,观察结缔组织生长因子(CTGF)在髁突软骨中分布的变化,探讨CTGF对前伸下颌后的髁突软骨的影响。方法:建立SD大鼠动物模型,选取45只5周龄SD 雌性大鼠,体重约100 g,随机分为对照组(20只)和实验组(25)只,组内再随机平均分为5组(3、7、14、21 和30 d)。实验组动物24 h佩戴改良可摘式上颌斜面导板矫治器,对照组动物不做处理。免疫组化染色标记CTGF,观察髁突软骨各层CTGF的表达变化。对CTGF的阳性表达量进行半定量分析。结果:对照组和实验组中髁突软骨组织中均有CTGF的表达,主要分布于肥大层和增殖层。实验组不同时间点髁突肥大层和增殖层中CTGF的平均光密度值分别高于对照组的平均光密度值(P<0.05 ) 。与对照组相比,实验组7 d后髁突肥大层和增殖层中CTGF的表达开始上升,到第14天达到最高,之后CTGF表达回落,但仍高于对照组(P<0.05 )。实验3 d、30 d,肥大层和增殖层中CTGF实验组与对照组相比无统计学差异。结论:CTGF可能参与了功能负荷改变所导致的髁突软骨适应性改建活动。     

Bone morphogenetic protein 3 expression pattern in rat condylar cartilage, femoral cartilage and mandibular fracture callus

Mandibular condylar cartilage differs from primary cartilage in morphological organization of the chondrocytes and in responses to biomechanical stress and humoral factors. For the first time, we describe the expression of Bmp3 mRNA in relation to types I, II and X collagen mRNA (as determined by in situ hybridization) in chondrocytes of the rat mandibular condylar cartilage, femoral articular cartilage, femoral growth plate cartilage, and temporal cartilage, which transiently appeared in the reparative response stage of mandibular ramus fracture healing. In all cartilages evaluated, Bmp3 was expressed in proliferating chondrocytes that expressed type I collagen in condylar cartilage, articular cartilage, and temporal cartilage appearing during fracture healing. Bmp3 was also found in hypertrophic chondrocytes that expressed type X collagen mRNA in all cartilages evaluated. Furthermore, in remodeling bone, Bmp3 mRNA was strongly expressed in active osteoblast cells in periosteal reaction layers formed after fracture. These findings suggest that Bmp3 expression in a special layer of typical articular cartilage may be regulated by mechanical stress stimulation. We also found that Bmp3 was expressed in the periosteal layers of the bone segments near the fracture site during fracture healing.     

骨保护素对去卵巢小鼠髁状突骨和软骨的影响

目的观察外源性骨保护素(osteoprotegerin,OPG)对去卵巢小鼠髁状突骨及软骨的影响。方法4月龄雌性未孕小鼠30只,其中20只行双侧卵巢摘除术,10只行假手术(A组)。4周后将双侧卵巢摘除20只随机分为B、C两组各10只,B组予安慰剂,C组皮下注射OPG 10 mg/kg,每周2次。治疗2个月后,测定各组动物髁状突的骨小梁面积、数量,软骨层的厚度及软骨层内部各层细胞的数量等。结果B组髁状突的骨小梁面积、数量较A组明显降低。C组髁状突的骨小梁面积、数量较A、B组明显增加,软骨层厚度增加、软骨层内部肥大细胞层较A、B组明显增厚。结论小鼠去卵巢后可成功建立髁状突骨质疏松模型;OPG对去卵巢小鼠髁状突有抑制骨吸收作用,并可能促进软骨细胞增殖,促使软骨细胞向成骨过渡。     

Age- and sex-related changes of mandibular condylar cartilage and subchondral bone: A histomorphometric and micro-CT study in rats

Objective

To quantify the age- and sex-related changes in the rat condylar cartilage and subchondral bone.

Methods

SD rats were obtained at the ages of 2, 3, 4, 5, 6 and 7 months. For each sex, the temporomandibular joints tissue blocks from four rats were subjected to histological assessment of cartilage thickness and subchondral bone architecture; for the remaining three rats, the mandibular condyles were delivered for gross measurement and evaluation of the mineralization and architecture properties of the subchondral bone by means of micro-CT.

Results

Rapid decrease of cartilage thickness but increase of subchondral bone density occurred respectively from 2 to 3 and 3 to 4 months old in female and 2 to 4 and 3 to 5 months old in male (P < 0.05), whereas rapid changes of subchondral bone architecture occurred from 3 to 4 months old in both sexes (P < 0.05). The significant enlargement of condyle size occurred at 4 or 5 months old in female but at 5 or 6 months in male (P < 0.05).

Conclusion

This study demonstrated that the rapid developmental changes of rat condylar cartilage and subchondral bone primarily occurred before 4 months of age, resulting in thinner cartilage but larger and thicker subchondral bone, and they were followed by rapid growth in condylar size. Sex differences were identified that the endochondral ossification of fibrocartilage and formation of subchondral bone were faster in female than in male rats, leading to the earlier enlargement of condyle in female than in male.     

Immunocytochemical detection of S-100 protein in rat mandibular condylar cartilage

Light and electron microscopic immunocytochemistry was used to localize S-100 protein. It was demonstrated in chondrocytes of the proliferative and hypertrophic zones but none could be found in the fibrous articular layer. The staining intensity for S-100 protein was stronger in the hypertrophic cells than in chondrocytes from the proliferative zone. Ultrastructurally, immunoreactive gold particles were detected in the cytosolic region, closely apposed to the profiles of endoplasmic reticulum with occasional dense aggregations. A few gold particles were seen on the nuclear chromatin and on condensing vacuoles of Golgi complexes. Because of the calcium-binding and possibly fatty acid-binding properties of the protein molecule, the immunocytochemical expression of S-100 protein in the chondrocytes may be involved in cartilage cell differentiation, metabolism and mineralization     

Immunohistochemical demonstration of bone morphogenetic protein in odontogenic tumors

The aim of the present study was to describe the expression and distribution of bone morphogenetic protein (BMP) in odontogenic tumors by immunohistochemistry using monoclonal antibody against bovine BMP (BMPMcAb). Eight types of odontogenic tumors (44 cases), including ameloblastoma (20 cases), cementifying fibroma (8 cases), benign cementoblastoma (5 cases), dentinoma (3 cases), compound odontoma (2 cases), adenomatoid odontogenic tumor (2 cases), calcifying epithelial odontogenic tumor (2 cases) and odontogenic fibroma (2 cases), were studied. The results showed that, according to the immunostaining pattern of BMPMcAb, tumors could be classified into two types: all cementifying fibro-mas, benign cementoblastomas. Dentinomas, odontogenic fibromas. and compound odontomas demonstrated a positive reaction, whereas all ameloblastomas, adenomatoid odontogenic tumors, and calcifying epithelial odontogenic tumors were negative. BMPMcAb-positive odontogenic tumors were those tumors with formation of enamel, dentin, cementum or bone. Therefore. BMP might play an important role in the formation of calcified dental tissues and the development of odontogenic tumors contaning such tissues.     

Efficacy of bone morphogenetic protein (BMP) with osteopromotive membranes – an experimental study in rat mandibular defects

The effect of bone morphogenetic protein (BMP) on healing of standardized bone defects was studied with and without the placement of osteopromotive membranes. Two different bovine BMP (bBMP) preparations were tested. These contained primarily collagen as a carrier. Standardized transosseous bone defects, 5 mro in diameter, were created in mandibles of rats. If left untreated, such "critical size defects" never heal during the lifetime of the animal, whereas covering with an osteopromotive membrane is known to cause complete healing of the defects in 6 weeks. The bBMP was implanted in defects and were either covered with an expanded polytetrafluoroethylene (e-PTFE) membrane (GORE–TEX®) or were left uncovered. Control defects did not receive any bBMP and were either covered with membrane or were left uncovered. Histological evaluation was made after 12 d and 24 d of healing, respectively. Implantation of bBMP alone was associated with formation of voluminous amounts of new bone, resulting in essentially complete defect healing at 24 d. However, the combination of membrane and bBMP was dearly less effective in stimulating bone healing, being only about as efficient as when using membranes alone. It was concluded that whereas both bBMP preparations were strongly osteoinductive, no further improvement of bone healing was seen when the membrane technique was supplemented with bBMP, compared to membrane alone. An explanation may be that the presence of an e-PTFE membrane prevents the degradation of the carrier material in the preparations, thus strongly reducing the availability of bBMP.     

磷脂酶C-γ1tyr783在下颌功能前伸大鼠髁突软骨后部表达变化的研究

目的 研究大鼠下颌功能前伸后髁突软骨中磷脂酶C-γ1 tyr783（PLC-γ1 tyr783）表达及其变化规律,探讨 PLC-γ1tyr783在功能矫治前伸大鼠下颌髁突软骨骨改建中的作用,为临床上骨骼矫形治疗提供实验依据。方法 选取4周龄健康雄性Sprague-Dawley（SD）大鼠60只,适应性饲养1周后随机等量分为实验组和对照组,实验组每天24 h佩戴自制下颌前伸斜面导板矫治器,对照组不戴矫治器。2组大鼠分别于戴用矫治器1、3、7、14、21、28 d时各断颈处死5只,取双侧髁突,常规固定、脱钙、脱水、包埋。石蜡切片采用免疫组织化学方法结合图像分析检测PLC-γ1tyr783在髁突软骨中的表达分布及其变化规律。结果 对照组PLC-γ1tyr783表达水平随着实验周期的推移逐渐减弱（P>0.05）,实验组大鼠髁突软骨处PLC-γ1tyr783的表达在第14天时达到高峰,与对照组相比差异有统计学意义（P<0.01）。结论 PLC-γ1tyr783参与了下颌功能前伸大鼠髁突软骨的骨改建。     

人牙周膜细胞中内源性骨形成蛋白的流式细胞仪分析

目的：定量检测和分析人牙周膜细胞（ＰＤＬＣ）表达内源性骨形成蛋白（ＢＭＰ）的情况。方法：应用ＢＭＰ单克隆抗体，通过流式细胞仪和免疫组化ＡＢＣ的方法双重判定。结果：在离体培养的人ＰＤＬＣ中有一半左右的细胞能表达ＢＭＰ。结论：牙周膜细胞具有一定的合成和分泌ＢＭＰ的能力；可以进一步认为人的牙周膜细胞是具有成骨潜能的，在牙周组织再生中有积极作用。