功能矫治后大鼠下颌髁突软骨中骨钙素基因表达的规律

目的　探讨生长发育期大鼠下颌髁突软骨中有无骨钙素mRNA的表达及其昼夜变化的规律。方法　采用SD大鼠 ,应用原位杂交技术检测大鼠下颌髁突软骨中骨钙素mRNA的表达 ,以图像分析半定量研究骨钙素mRNA表达的昼夜变化规律。应用宏观、微观分析法进行统计分析。结果髁突软骨内有骨钙素mRNA的表达 ,峰值相位约在上午 6时左右。戴用功能矫治器后骨钙素mRNA表达增强 ,其中 2 4h组升高幅度较 12h组明显。结论　生长发育期大鼠下颌髁突软骨中骨钙素mRNA的表达呈现昼夜节律性。功能矫治后髁突软骨中骨钙素mRNA含量增加 ,2 4h加力组增高的幅度均高于 12h组 ,说明戴用功能矫治器时间越长 ,效果越明显     

前伸下颌后大鼠髁突内源性胰岛素含量昼夜节律变化的研究

目的：研究前伸大鼠下颌后,大鼠髁突内源性胰岛素（Ｉｎｓ）含量昼夜节律变化,探讨功能矫治器在一天中的最佳戴用时段,方法：采用放射免疫学技术,测定生长期大鼠在自然状态及不同时间段（白天或夜晚）戴用同一功能矫治器前伸下颌时,大鼠髁突内源性Ｉｎｓ含量在１昼夜内每４ｈ的变化。结果：自然状态下,生长期大鼠髁突内源性Ｉｎｓ含量存在昼夜节律,峰值相位约在１２：１３,功能矫治器前伸下颌后,此节律性并未消失;白天戴用     

细胞增殖与程序性细胞死亡在颞下颌关节发育中的意义

目的：探讨细胞增殖与程序性细胞死亡在颞下颌关节发育中的作用。方法：利用免疫组织化学技术及原位末端标记法,对胚胎及生后一周ＳＤ大鼠颞下颌关节不同发育时期髁状突软骨中增殖细胞核抗原（ＰＣＮＡ）的表达及程序性细胞死亡（ＰＣＤ）进行了观察。结果：胎鼠颞下颌关节髁状突软骨增殖层ＰＣＮＡ阳性细胞率最高,进入浅层肥厚层ＰＣＮＡ阳性细胞数减少,深层肥厚层中则未见ＰＣＮＡ阳性细胞。出生后髁状突软骨ＰＣＮＡ阳性细胞率均较出生前低。ＰＣＤ阳性细胞主要分布于软骨增殖层及邻近深层肥厚层的浅层肥厚层中,在关节腔开始形成时髁状突软骨表面ＰＣＤ明显。结论：细胞增殖与程序性细胞死亡密切相关,协同参与调控颞下颌关节的生长发育与塑形。     

功能矫治前伸大鼠下颌髁突中甲状旁腺相关蛋白(PTHrP)基因表达的季节性变化规律

目的探讨生长发育期大鼠下颌髁突软骨中甲状旁腺相关蛋白mRNA的表达特征及其季节性变化规律。方法采用SD大鼠，应用原位杂交技术检测大鼠下颌髁突软骨中甲状旁腺相关蛋白的mRNA表达，图像分析半定量研究甲状旁腺相关蛋白mRNA的季节性变化规律，应用宏观、微观分析法进行统计分析。结果髁突软骨细胞中有甲状旁腺相关蛋白mRNA的表达，并有季节性变化规律；戴用功能矫治器后其表达信号增强。一月中旬到二月初增强的最明显。结论功能矫形治疗受季节变化影响，模拟功能矫形治疗的生长发育期大鼠在二月份左右戴用矫治器矫治效果更明显。     

大鼠髁突软骨增殖细胞核抗原表达的昼夜节律

目的：了解髁突软骨细胞增殖的昼夜节律性,为探讨一天中临床功能矫形治疗介入的最佳时段提供初步实验依据。方法：应用免疫组织化学方法对生长期大鼠髁突软骨细胞增殖细胞核抗原（PCNA）表达进行检测分析,结果：大鼠髁突软骨细胞的PCNA表达,存在明显的昼夜节律性,其峰值相位约在12：00,谷值相位约在0：00。结论：髁突软骨细胞增殖存在昼夜差异性,其高峰期在白天,功能矫治一天中,可能存在最佳时段。     

甲状旁腺相关蛋白在大鼠髁突软骨中的表达及其季节性变化规律

目的 探讨生长发育期大鼠下颌髁突软骨中甲状旁腺相关蛋白（PTHrP）的表达特征及其季节性变化规律。方法 采用64只SD大鼠,随机等量分为白天12 h加力组和对照组,应用免疫组织化学技术检测大鼠下颌髁突软骨中PTHrP的表达,图像分析半定量研究PTHrP的季节性变化规律,应用宏观和微观分析法进行统计分析。结果 所有大鼠髁突软骨各层细胞中均有PTHrP的表达,并有季节性变化规律。戴用功能矫治器后其表达信号增强。冬末春初增强的最明显。结论 生长发育期大鼠下颌髁突软骨中有PTHrP的表达,且表达呈现季节性变化规律。功能矫形治疗可增加大鼠髁突内源性PTHrP的表达,冬末春初效果更明显。     

前伸下颌后大鼠髁突软骨内明胶酶表达变化的研究

目的研究前伸下颌后明胶酶（MMP- 2、MMP- 9）在大鼠髁突软骨内表达的变化。方法选取5周龄雄性SD大鼠60只,随机等量分成实验组和对照组,实验组大鼠白天配戴自制的上颌斜面导板式活动矫治器引导下颌前伸,对照组大鼠不戴矫治器。在实验的1、2、4周处死动物,免疫组化检测明胶酶在大鼠髁突软骨内表达的变化。结果在正常髁突软骨内,MMP- 2呈中等强度表达,MMP- 9表达很低。前伸下颌后,髁突软骨内MMP- 2的表达无明显变化,而MMP- 9的表达显著增高（P<0.01）。结论明胶酶参与了功能矫形时下颌髁突软骨的适应性改建。     

功能矫形前伸大鼠下颌后的髁突组织学和组织化学观察

采用自制上颌功能矫治器前伸生长期Ｗｉｓｔａｒ大鼠下颌从青春期至成年后，应用组织学和粘液组织化学方法，对髁突软骨细胞形态和功能进行研究，结果发现，未持续戴矫治器的实验Ａ组髁突前份软骨回复性增生，髁突后份软骨生长降低，持续戴矫治器的实验Ｂ组髁突后份软骨有持续增生的趋势，提示，功能矫形治疗安氏Ⅱ类下颌发育不足畸形时，矫治后应昼增长保持时间。     

大鼠下颌功能前伸后激活髁突胰岛素样生长因子1基因表达

目的研究用功能矫治器前伸生长期大鼠下颌后，髁突软骨中胰岛素样生长因子（ＩＧＦ１）基因表达的变化规律，探讨功能矫形治疗的分子机理。方法将６０只雄性５周龄ＳＤ大鼠分为对照组和实验组，按１天、３天、１周、２周、３周和４周６个阶段，应用原位杂交技术研究髁突软骨中ＩＧＦ１ｍＲＮＡ的表达变化。结果正常生长期大鼠下颌髁突软骨有ＩＧＦ１ｍＲＮＡ表达；前伸大鼠下颌使髁突软骨细胞中ＩＧＦ１ｍＲＮＡ阳性强度和阳性细胞数目均增加。这一变化具有时间性，即实验３天后开始升高，实验后１周～２周达最高值，３周～４周时逐渐降低。结论功能前伸下颌后ＩＧＦ１ｍＲＮＡ转录升高，表明功能矫形后髁突软骨的生长改建可能是由于咀嚼肌牵张激活了ＩＧＦ１的基因表达。     

前伸大鼠下颌后髁突局部甲状旁腺激素相关蛋白含量的季节性变化规律

目的 :探讨不同季节给生长发育期大鼠戴用功能矫治器后 ,其髁突局部的甲状旁腺激素相关蛋白 (PTHrP)含量的季节性变化规律。方法 :选用SD大鼠 ,采用免疫放射法计测大鼠髁突局部甲状旁腺激素相关蛋白含量的变化 ,应用宏观、微观分析法进行统计分析。结果 :生长发育期的大鼠在自然状态下 ,其髁突局部甲状旁腺激素相关蛋白含量存在着季节性变化规律。戴用功能矫治器后 ,其髁突局部甲状旁腺激素相关蛋白含量的季节性变化规律仍存在 ,冬末春初含量最高 ,夏季最低。结论 :季节变化对功能矫形治疗有影响。     

下颌前伸后髁突软骨成熟层内X型胶原的表达

目的：检测下颌骨前伸条件下,大鼠髁突内Ｘ型胶原的表达,从而论证髁突新骨的形成状况。方法：１００只同源雌性大鼠５组实验组及５组对照组,实验组动物戴用统一规格的咬合前导矫正器,各实验组及相应对照组动物分别在实验的第３、７、１４、２１及３０ｄ处死。应用分子原位杂交及免疫组织化学技术对髁突软骨成熟慨内的Ｘ型胶原ｍＲＮＡ及其蛋白的表达进行评价。结果：实验组,特别是２１ｄ组动物其髁突软骨成熟层细胞内有强烈的Ｍ     

Functional appliance therapy accelerates and enhances condylar growth.

The present study was designed to quantitatively assess the temporal pattern of expression of Sox 9, the regulator of chondrocyte differentiation and type II collagen, the major component of the cartilage matrix during forward mandibular positioning, and compare it with the expression during natural growth. Female Sprague-Dawley rats, 5 weeks old, were used. Results showed that the expression of Sox 9 and type II collagen are accelerated and enhanced when the mandible is positioned forward. Furthermore, we monitored the amount of new bone formation during mandibular advancement and after the removal of bite-jumping appliances. A substantial increase was observed in the amount of newly formed bone when the mandible was positioned forward. No significant difference in new bone formation could be found after the appliance was removed when compared with natural growth. Thus, functional appliance therapy accelerates and enhances condylar growth by accelerating the differentiation of mesenchymal cells into chondrocytes, leading to an earlier formation and increase in amount of cartilage matrix. This enhancement of growth did not result in a subsequent pattern of subnormal growth for most of the growth period; this indicates that functional appliance therapy can truly enhance condylar growth.     

升高咬合对青春期大鼠髁突软骨中增殖细胞核抗原表达变化的影响

目的：探讨升高咬合后髁突软骨中增殖细胞核抗原（PCNA）的变化情况及意义。方法：40只5周龄雄性SD大鼠,随机分为对照组和实验组（双侧后牙板升高咬合）。分别于术后7、14、21及28d,取其右侧髁突,应用免疫组织化学SABC法检测大鼠髁突软骨中PCNA的表达变化,并作图像分析和统计学处理。结果：与对照组相比,实验组髁突软骨PCNA阳性细胞表达在实验第7、14d明显减少,第28d明显增多（P〈0.05）。结论：咬合升高可以引起大鼠髁突软骨的适应性改建。     

Propulsive appliance stimulates the synthesis of insulin-like growth factors I and II in the mandibular condylar cartilage of young rats

Functional orthopedic appliances correct dental malocclusion partially by exerting indirect mechanical stimulus on the condylar cartilage, modulating growth and the adaptation of orofacial structures. However, the exact nature of the biological responses to this therapy is not well understood. Insulin-like growth factors I and II (IGF-I and IGF-II) are important local factors during growth and differentiation of several tissues, including cartilage. The aim of this study was to verify the mRNA and protein expression of IGF-I and IGF-II in the condylar cartilage of young male Wistar rats that used a mandibular propulsive appliance for 3, 5, 7, 9, 11, 13 or 15 days. For this purpose, sagittal sections of decalcified and paraffin-embedded condyles were submitted to immunohistochemistry and in situ hybridization. IGF-I and IGF-II expression increased with developmental age in the control and treated rats. After 9 days of treatment the positivity for both peptides in the animals that wore the propulsive appliance increased even more, expressively different from the age-matched controls. The expression patterns of both IGFs were similar, although IGF-I labelling was stronger. Furthermore, the enhanced expression of both peptides was in parallel with the proliferating cell nuclear antigen (PCNA) positivity, a proliferation cell marker. The modulation of IGF-I and IGF-II expression in the condylar cartilage in response to the propulsive appliance suggests that both peptides are involved in the mandibular adaptation during this therapy.     

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??Objective    Objective To investigate the changes in the expression of DMP-1 in the condylar of a young rat during functional mandibular protrusion. This work also explores the function of DMP-1 in the cartilage proliferation??which provides experimental evidence for the clinical orthopedic treatment for bone type II malocclusion. Methods     Totally 70 healthy male Sprague-Dawleys ??SD?? rats at the age of 4 weeks were included in the study. The rats were divided randomly and equally into experimental group and control group. The mandibular protrusion bite plate appliances that were fitted to the animals in the experimental group were worn all day. No operation was performed in the control group. Five rats were executed in each group after 1??3??7??14??21??28 and 35d. Detect the expression and variation of DMP-1 by immunohistochemical method and cell image analysis system. Results    On the 3rd day??the expression of DMP-1 in condylar cartilage was obviously enhanced in the experimental group. which reached to the highest level on the 14th day??IHS= 85.67±4.51, which had significant difference ??P < 0.05?? compared with control group??IHS=10.67±1.53. Conclusion    DMP-1 participates in condylar cartilage adaptive remodeling during the process of mandibular protrusion of rats??and promotes condylar cartilage proliferation and endochondral ossification.     

Induction of insulin-like growth factor I expression to mandibular advancement in growing rat condylar cartilage]

It was studied effects of functional mandibular advancement on IGF-I peptide of condylar cartilage of 60 5-week-old male rats. Animals were randomly divided into the experimental and control groups, and the mimic functional appliances were used in experimental group. The rats were killed after 1, 3, 7, 14, 21 and 28 days. The results showed that the condylar cartilage of growing rats expressed IGF-I the strongest in the germinal layer, medial in the transitional layer, and the least in the maturational layer. IGF-I positive cells and their immunoreactive levels increased after 1 week of functional mandibular advancement, and reached the peak level at 2 weeks. The results suggest IGF-I in mandibular condyle of rat is related to its growth and differentiation activity, and changes of condylar IGF-I after functional protrusion are relevant to the histologic changes and cellular functions which indicate their involvement with active bone growth and remodeling.