骨形态计量学观察睾酮对雄性去势大鼠松质骨的影响

目的 通过骨形态计量方法观察雄激素替代疗法对去睾丸致骨质疏松大鼠不同部位松质骨的影响。方法30只4月龄SD雄性火鼠，随机分成基础对照组（A组、实验开始时处死），年龄对照组（B组）、去睾丸组（C组）和去睾丸加睾丸酮组（D组），B组和C组每日生理盐水5ml／kg，D组每日甲基睾丸酮片1．8mg／kg，灌胃90d。实验结束，处死全部大鼠，取胫骨上段和第5腰椎进行不脱钙骨制片，用计算机全自动图象分析系统进行骨组织形态计量学分析。结果 大鼠去睾丸后胫骨上段骨量下降，骨形成和骨吸收都增加；腰椎骨量也下降，骨吸收也增加，但骨形成表现为降低。睾酮能阻止去睾丸后胫骨上段的骨量丢失（％Tb．Ar＋44．8％，P〈0．05），降低骨高转换；但不能完全阻止腰椎的骨量丢失，只能抑制骨吸收，对骨形成影响不大。结论 雄激素替代治疗能阻止雄激素水平下降造成的大鼠松质骨的骨量丢失，胫骨上段对雄激素的敏感性比腰椎部位的高。     

卵巢切除对大鼠皮质骨结构和力学性能的影响

目的：研究卵巢切除大鼠皮质骨的几何学改变和力学性能改变,探讨雌激素缺乏时皮质骨改变的发生机理。方法：选雌性SD大鼠56只,分为Sham组和OVX组,动物分别在4、12、20和28周时处死7只,取其胫骨备用。左侧于近3/5和远2/5交界部切断,在电镜下摄片,计测截面总面积、皮质骨面积、骨外径周长、骨髓腔面积和骨内径周长。右侧以近3/5与远2/5交界点为加载点进行三点弯曲力学实验。结果：Sham组术后4周至28周胫骨截面总面积和骨外径周长逐渐增加。（P＜0.005),而髓腔面积和内径周长变化不明显。OVX组截面总面积和外径周长也有逐渐增加趋势。但差异无显性。而内径周长和髓腔面积都明显增加,在相同时期显大于Sham组（P＜0.005),而皮质骨面积却与Sham组差异无显性。三点弯曲试验结果表明,从4-28周实验对照两组抗弯强度和刚度均逐渐增加,但两组间差异无显性。在各时期骨组织材料力学性能也无显性差异。结论：卵巢切除对皮质骨的影响主要表现在使骨髓控扩大,对骨外膜的影响较小,在短期内皮质骨的力学性能无明显影响。     

骨形态计量学评价低钙对大鼠皮质骨的作用研究

目的 评价低钙饮食对大鼠皮质骨的影响。方法 3月龄SD普通级雄性大鼠40只，随机分为5组。第1、2组饲养1个月，分为正常对照组(1mol，ca1．0％)和极低钙组VLCD(1mol，Ca0．1％)，余下3组饲养3个月，分为正常对照组(3mol，Ca1．0％)、极低钙组VLCD(3mol，Ca0．1％)和低钙组LCD(3mol，Ca0．3％)。各组动物喂养包含对应钙含量的精制饲料，处死前进行双荧光标记。实验结束时，取左侧胫骨中段行骨形态计量学检测。结果 无论是低钙饮食1个月，还是3个月，无论是极度缺钙，还是仅有轻微的钙不足，胫骨中段横截面皮质骨始终未出现显著意义的变化，但骨内膜骨吸收有增加的趋势。结论 低钙对皮质骨作用不明显，这可能与机体在低钙状态下动用骨骼的次序或快慢有关。     

老年大鼠松质骨骨重建的组织形态计量学研究

目的：研究老年大鼠及在促骨合成药前列腺素E2（PGE2）作用下松质骨骨重建和骨建造的形态计量学改变，探讨动物骨重建形态学新参数测量方法及其意义。方法：50只20月龄雄性Wistar大鼠随机分成5组，年龄对照组（基础组、10d和30d年龄对照组），PGE2给药组（分别10d和30d给予3mg/kg/d处理组）。用体内双荧光标记，不脱钙组织切片，粘合线（cement line）染色，骨组织形态计量学方法，测定骨重建和骨建造参数。结果：20月龄雄性大鼠胫骨近端松质骨的形成表面大多数为骨重建单位（占63．3％），少部分为骨建造单位（占26．7％）；PGE2用药后骨重建单位增加1．5倍，骨建造单位增加4倍，比值倒置，成骨细胞10d时明显增多。说明PGE2通过刺激成骨细胞骨合成而介民导骨建造性骨增加和骨重建性骨量增加，并以前为主。结论：老年雄性大鼠 松质骨以骨重建活动为主，仍有骨建造活动。PGE2主要通过刺激成骨细胞骨建造而增加骨量。     

雌激素下降与低负荷对松质骨结构影响的形态计量学观察

雌激素下降与低负荷对松质骨结构影响的形态计量学观察戴克戎，阎景龙雌激素下降、增龄和骨载荷改变，是诱发骨质疏松最常见的致病因素。我们通过系列实验研究，观察了卵巢切除和低应力环境对实验动物后肢松质骨与皮质骨的影响。本文为其中松质骨组织形态计量学检测结果的...     

低负荷对大鼠皮质骨结构和力学性能影响的实验研究

为了进一步探讨低负荷(废用)对皮质骨的影响．本研究从几何形态和力学性能方面现察了大鼠胫骨皮质骨的变化。实验选240g雌性S-D大鼠56只，随机分为对照及实验两组。实验组行左后肢固定造成肢体废用模型。实验动物分别于4、12、20和28周处死，取胫骨进行三点弯曲试验及其横断面的形态计量学观察．根据三点弯曲试验记录的载荷一变形曲线，分析胫骨的材料力学性能和结构力学性能。形态计量学观察主要检测胫骨截面的截面总面积、皮质骨面积、外径周长、骨髓腔面积和骨内径周长。实验结果表明，从实验4周至28周．对照组胫骨截面总面积和骨外径周长明显增加(P<0．05)。而实驻组截面总面积、骨外径周长则没有明显增加，实验20周后二明显低于对照组(P相似文献   

降钙素对正常成年雄性大鼠骨重建过程的影响

目的 在体研究降钙素对成年雄性大鼠松骨重建过程的影响,并分析其影响机制。方法 １２只大鼠平均分成对照组和降钙素组,后皮内注射鳗鱼降钙素１Ｕ／１００ｇ／日,连续２日。７日后取第４、５腰椎,行不脱钙骨组织切片,骨组织形态计量学分析,方差分析比较两组结果。结果 骨吸收陷窝表面、活性吸收表面、破骨细胞平均细胞核数,降钙素组明显小于对照组。类骨质表面、类骨质相对体积、类骨质厚度,降钙素组明显小于对照组,成     

补肾中药复方延缓老年雄性大鼠股骨皮质骨、松质骨骨量增龄性丢失的实验研究

目的　研究补肾中药复方延缓老年大鼠股骨皮质骨 、松质骨骨量增龄性丢失的作用。方法３６只２４月龄 Ｓ Ｄ 雄性大鼠随机分为２４月龄本底对照组、３０月龄增龄对照组、补肾中药复方低剂量组、补肾中药复方高剂量组,每组各９只。低剂量组、高剂量组均自２４月龄给药至３０月龄。各组相应处理以后分别测定各组大鼠左侧股骨以松质骨为主的近段、远段以及以皮质骨为主的中段的骨密度。结果　补肾中药复方低剂量组大鼠股骨各段骨密度增龄性减少率出现延缓的趋势;高剂量的补肾中药复方则能明显延缓股骨各段骨密度增龄性减少率。结论　补肾中药复方具有量效依赖性地延缓大鼠皮质骨、松质骨增龄性骨丢失的作用     

雄激素对男性骨质疏松大鼠模型骨的影响

目的 运用骨密度检查、骨生物力学和形态计量学方法 ,观察雄激素睾丸酮对老龄雄性去势大鼠骨组织的作用,并探讨其作用机理,为男性骨质疏松症治疗提供思路.方法 30只12月龄雄性Wistar大鼠随机分为去势组、治疗组和假手术组,每组10只.治疗组行睾丸及附睾切除术后,睾丸酮灌胃给药(26.7 mg·kg-1·d-1),12周后取材.运用双能x线骨矿含量测定仪(DXA)检测治疗前后大鼠全身总骨密度(BMD),取大鼠左侧股骨、L-5椎体作生物力学测试,取左侧胫骨近端作骨组织形态计量学测试.结果 雄激素睾丸酮可以提高治疗组去势大鼠骨密度,生物力学检测发现,雄激素治疗组大鼠力学参数:骨最大载荷(M-load)、吸收能量(Enery)、最大应力(M-stress)、弹性模量(E-lastic)值较去势组有明显增加,骨形态计量学观察发现骨形成参数、骨吸收参数及骨矿化参数值较去势组均有明显增加,骨形成大于骨吸收.结论 雄激素睾丸酮能促进骨形成及骨转换、改善骨结构,增加骨强度和骨密度.     

去卵巢对大鼠皮质骨微结构、骨密度及生物力学的影响

目的 应用显微CT和四点弯曲实验观察去卵巢对大鼠股骨皮质骨骨密度、微结构及生物力学性能的影响.方法 24只7月龄雌性SD大鼠随机分为去卵巢(OVX)组和假手术(Sham)组,于手术后3周、15周各处死6只,显微CT扫描左侧股骨中段.右侧股骨行四点弯曲试验.结果 去卵巢3周至15周,OVX组股骨皮质骨内径周长、外径周长、皮质骨面积、骨髓腔面积、截面总面积骨密度、最大力、弹性模量、断裂强度与Sham组相比无明显差异(P＞0.05).OVX组15周弹性模量比3周低36％ (P ＜0.05).结论 去卵巢15周内大鼠股骨中段皮质骨微结构及其骨密度和股骨力学性能无明显变化,但去卵巢组股骨生物力学性能减退较快.     

Non-invasive axial loading of mouse tibiae increases cortical bone formation and modifies trabecular organization: a new model to study cortical and cancellous compartments in a single loaded element

Systematic study of bones' responses to loading requires simple non-invasive models in appropriate experimental animals where the applied load is controllable and the changes in bone quantifiable. Herein, we validate a model for applying axial loads, non-invasively to murine tibiae. This allows the effects of mechanical loading in both cancellous and cortical bone to be determined within a single bone in which genetic, neuronal and functional influences can also be readily manipulated. Using female C57Bl/J6 mice, peak strains at the tibial mid-shaft were measured during walking (<300 με tension) and jumping (<600 με compression) with single longitudinally oriented strain gauges attached to the bone's lateral and medial surfaces. Identically positioned gauges were also used to determine, for calibration, the strains engendered by external applied compressive tibial loading between the flexed knee and ankle ex vivo. Applied loads between 5 and 13 N produced strains of 1150–2000 με on the lateral surface, and in vivo repetitions of these loads on alternate days for 2 weeks produced significant load magnitude-related increases in cortical bone formation that were similar in mice at 8, 12 and 20 weeks of age. Micro-CT scans showed that loading significantly increases trabecular bone volume in 8 week old mice, but modifies trabecular organization with decreases in trabecular bone volume in 12 and 20 week old mice. This model for loading the tibia has several advantages over other approaches, including scope to study the effects of loading in cancellous as well as cortical bone, against a background of either disuse or of treatment with osteotropic agents within a single bone in normal, mutant and transgenic mice.     

The cancellous bone of the iliac crest

A study of the thickness and spacing of bony structures in the cancellous bone of the iliac crest. Ground sections of methacrylate-embedded material from 67 normal subjects, from 20 to 90 years of age, were examined. Increasing age is accompanied by an increase in the spacing between the bony structures, but not by any significant reduction in their thickness. The thinnest bony structures appear to be undergoing the most remodelling, as judged by the extent of formation and resorption surfaces.

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Zusammenfassung Die Dicke der Trabekel und die Weite der Markzwischenräume des Hüftbeinkammes wurden bestimmt. Das in Methacrylat eingebettete Material, welches von 67 Normalpersonen im Alter von 20–90 Jahren stammte, wurde geschnitten und untersucht. Bei zunehmendem Alter vergrößert sich der Raum zwischen den Trabekeln, ohne daß jedoch deren Dicke signifikant vermindert wird. Gemessen am Umfang der Bildungs- und Resorptionsoberfläche scheinen die dünnsten Trabekel dem größten Knochenumbau unterworfen zu sein.

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Résumé Une étude de l'épaisseur et de l'espacement des structures osseuses dans l'os d'aspect réticulé du crête iliaque. Les specimens provenant de 67 sujets normaux, ages de 20 à 90 ans, furent enfoncés dans methacrylate et tranches preparés par meulage. L'age croissant est accompagné d'une augmentation de l'espacement entre les structures osseuses, mais pas d'une reduction signifiante de leur épaisseur. Les structures osseuses les plus minces paraissent subir le plus grand remondellage, jugant par l'importance de surfaces de formation et de résorption.

     

Mechanical properties of microcallus in human cancellous bone.

Until now, the mechanical properties of the microcalluses that form in human cancellous bone have been unexplained. We measured the microhardnesses of microcalluses in cancellous bone, of the trabeculae within the microcalluses, of the trabeculae adjacent to microcalluses, and of trabeculae lacking microcalluses in a human tibia and femur. We observed no important differences between materials at the four different sites. Because the microhardness of bone is very closely related to its stiffness, this finding indicates that microcalluses are likely to stiffen the trabeculae in which they are formed, even though they may surround unhealed fractures of the cancellous trabeculae.     

Supraphysiologic levels of testosterone affect cancellous and cortical bone in the young female Cynomolgus monkey

The goal of this study was to evaluate the effects of chronically-elevated male levels of the potent androgen testosterone on the quality and quantity of both cancellous and cortical bone in a young (mean age 8.0 years), nonhuman female primate model (M. fascicularis). Thirteen intact female monkeys received continuous testosterone supplementation via subcutaneous implants over a 24-month period. A group of 16 untreated, intact, age-matched female monkeys served as controls. At sacrifice, the lumbar vertebrae and femora were recovered in order to analyze the bone mineral quality and quantity of cancellous and cortical bone, respectively, and compared to the control group. Mineralization profiles of the vertebrae and femora were obtained using the density fractionation technique. Chemical analysis of the three largest fractions retrieved by density fractionation was performed to evaluate differences in %Ca, %P, Ca/P ratio, and mineral content (%Ca + %PO₄) between the control and experimental groups. In addition, unfractionated bone powder was examined by X-ray diffraction to identify any changes in crystal size. Coronal sections of vertebrae were analyzed for structural parameters using histomorphometry and image analysis. Cross sections taken at the midshaft diaphyseal femora were analyzed for structural macroscopic and intracortical parameters. A nonsignificant shift in the mineralization profile of the vertebrae was observed whereas there was a significant shift in the mineralization profile towards more dense bone in the treated femora as compared with controls (P < 0.05). There was no difference in terms of size/strain of the cortical or cancellous bone crystal as detected by X-ray diffraction. There was a trend towards an increase in cancellous bone area (B.Ar.) in the testosterone-treated vertebrae (P= 0.08) as compared with controls. The architecture of the cancellous bone remained nonsignificantly different between the treatment and control groups as evaluated by image analysis. There was a decrease in osteoid perimeter (P= 0.05) in the experimental group as compared with controls. There was a significant decrease in eroded perimeter measurements in the experimental group as compared with controls (P < 0.03). Although there was a trend towards an increase in cancellous bone area, mineralization was not significantly different in the vertebrae of testosterone-treated female monkeys, indicating that the newly-formed bone tissue became relatively normally mineralized over the two-year period. An increase in bone area, with indices of an overall decreased remodelling pattern as compared with controls, suggests that cancellous bone in the young, nonhuman female primate had been receptive to supraphysiologic levels of testosterone supplementation over the two-year period. There was a trend for an increase in cortical bone area and width with an increased periosteal perimeter in the testosterone-treated group as compare with controls. There was an increase in intracortical remodelling activity with a significant increase in percent porosity (P < 0.05), osteonal bone (P < 0.05), and mean wall width (P < 0.05) in the testosterone-treated group. In conclusion, the cancellous bone from female monkeys appeared to respond to the antiresorptive stimulus of male levels of testosterone with significantly diminished turnover parameters in this compartment. In contrast, the cortical bone compartment responded by displaying significant intracortical remodelling over a two-year period. Received: 22 December 1995 / Accepted: 3 April 1996     

松质骨显微结构参数与表观力学强度关系研究进展

通过双能X射线吸收法测量受试者的骨密度,是目前公认的诊断骨质疏松症的方法。然而,越来越多的基础和临床研究发现,骨密度的改变并不能完全解释患者骨强度的改变。大量的骨组织显微结构研究发现,松质骨的骨强度主要由骨密度、骨结构等因素决定。近年来的研究表明,在决定松质骨骨骼强度方面,骨组织的显微结构可以作为独立于骨密度之外的决定性参数。研究松质骨的力学属性和显微结构之间的关系,对于更好的理解骨质疏松的发生和对骨质疏松的诊断具有十分重要的意义。根据文献回顾,松质骨显微结构参数和表观力学强度之间关联性最为显著的为BV／TV、Tb．N、连接性、各向异性、结构模型指数等。同时笔者也对目前这些研究结果在临床上高分辨率CT上的应用情况做一总结。     

The effect of bone loss on rod-like and plate-like trabeculae in the cancellous bone of the mandibular condyle

Bone loss may affect the structure of cancellous bone. But its effect on trabeculae with different characteristics, like rods and plates, is not accurately known. This study analyzes the effect of bone loss on individual rod-like and plate-like trabeculae. 94 specimens were obtained from mandibular condyles from both dentate and edentate humans and scanned with a micro-CT scanner. The bone volume fraction (BV/TV) of these specimens ranged from 7% to 30%. Next, the rod-like and plate-like trabeculae were identified with an especially developed algorithm. Plate volume fraction (PV/TV), rod volume fraction (RV/TV), plate thickness, rod thickness, number of plates, and number of rods were determined. In individual specimens, the thickness of the rods ranged from 40 μm to 180 μm, while the thickness of the plates ranged from 40 μm to 300 μm. In every specimen, the thickness of the plates was larger than the thickness of the rods. Statistical analysis revealed that PV/TV was proportional (r = 0.98, P < 0.001) and RV/TV inversely proportional (r = −0.45, P < 0.001) to BV/TV. Also the thickness of the plates correlated with BV/TV (r = 0.62, P < 0.001), while the thickness of the rods (mean = 90 μm, SD = 7 μm) remained constant (r = −0.09, P = 0.378). A four-fold reduction of the bone volume fraction was accompanied by a three-fold reduction of the number of plates and a 40% reduction of their thickness, but also by a three-fold increase in the number of rods and RV/TV. It was concluded that the effect of bone loss on plate-like trabeculae was opposite to its effect on rod-like trabeculae. Remarkably, the thickness of the rods (90 μm) was independent of the bone volume fraction. This suggests that there is a minimal thickness for trabeculae.     

Ageing patterns of trabecular and cortical bone and their relationship

Trabecular bone mass was measured in the iliac crest of 129 cadavera of both sexes with a physical method based on the principle of Archimedes. Cortical bone mass was measured at the second metacarpal of the right hand with a graphimetric X-ray method in 77 cases.Trabecular and cortical bone mass decreased significantly with age in women but not in men. A significant correlation between cortical and trabecular bone mass was established in women.

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Zusammenfassung Die trabeculäre Knochenmasse von 129 Leichen beiden Geschlechts wurde gemessen. In 77 Fällen wurde auch die corticale Knochenmasse gemessen. Die trabeculäre Knochenmasse von Beckenkammproben wurde mit einer physikalischen Methode bestimmt, welche auf dem Prinzip des Archimedes basiert. Die corticale Knochenmasse wurde am zweiten Metacarpus der rechten Hand mittels einer graphimetrischen Röntgenmethode gemessen.Die trabeculäre und die corticale Knochenmasse nahm bei Frauen, aber nicht bei Männern, mit zunehmendem Alter stark ab. Bei Frauen wurde eine signifikante Korrelation zwischen corticaler und trabeculärer Knochenmasse festgestellt.

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Résumé La masse de l'os spongieux de 129 cadavres des deux sexes a été déterminée. Dans 77 cas, la masse de l'os cortical est également mesurée. La masse de l'os spongieux d'os de la crête iliaque est établie à l'aide d'une méthode physique, basée sur le principe d'Archimède. La masse de l'os cortical est mesurée au niveau du second métacarpe de la main droite à l'aide d'une méthode graphimétrique aux rayons X.La masse de l'os spongieux et cortical décroit significativement avec l'âge chez la femme, mais non chez l'homme. Une corrélation significative a pu être établie chez la femme entre la masse de l'os cortical et spongieux.

     

Subchondral bone sclerosis and cancellous bone loss following OA induction depend on the underlying bone phenotype

Objectives

Osteoarthritis (OA) is increasingly considered a disease of the whole joint, yet the interplay between the articular cartilage and the subchondral bone remains obscure. We here set out to investigate the impact of bone mass on the progression of surgically induced knee OA in the mouse.

The effects of continuous progestogen treatment on cortical bone remodeling activity in beagles

Summary Cortical bone remodeling measurements were carried out on the ribs of 6 spayed and 5 progestogen-treated spayed Beagle dams which had been subjected to a period of observation equal to more than 1 sigma of intact canine bone remodeling activity. Analyses of static and dynamic features indicated that continuous medroxyprogesterone acetate replacement therapy altered the rates of cortical bone remodeling activity. In the progestogen-treated dams, more Basic Multicellular Units (BMUs) were activated, exhibiting shortened resorption and formation times. Thus, this progestogen appears to play a significant role in regulating cortical bone cell activity and, as such, suggests that progesterone may play a part in the prevention or slowing down of cortical bone loss in females following menopause or oophorectomy.     

Low-megahertz ultrasonic properties of bovine cancellous bone

Ultrasound offers a noninvasive means to detect changes that occur to the density of cancellous bone as a result of degenerative diseases such as osteoporosis. Techniques based on the velocity and frequency dependence of attenuation of ultrasonic pulses propagated through cancellous bone have proven sensitive to bone density. Most previous studies have investigated these two parameters in the frequency range of 0.1–1.0 MHz. The present study had two goals. The first was to measure three ultrasonic parameters: longitudinal mode velocity; broadband ultrasonic attenuation (BUA); and apparent integrated backscatter (AIB), at higher frequencies using a broadband 2.25 MHz measurement system. The second goal was to assess the dependence of these parameters on bone density. Twenty-one specimens of cancellous bone acquired from the proximal end of four bovine tibiae were investigated in this study. The apparent density of the specimens (determined with the bone marrow removed and the specimens thoroughly dry) ranged between 0.3 and 0.9 g/cm³. Ultrasonic measurements were performed along three mutually perpendicular directions corresponding to the anteroposterior (AP), mediolateral (ML), and superoinferior (SI) axes of the tibia. A linear regression was used to analyze the results of these measurements as a function of apparent density. Velocity demonstrated a highly significant linear increase with density for all three directions (AP: p < 0.001; ML: p < 0.001; SI: p < 0.01). AIB decreased with density in all three directions; however, only the ML and SI directions demonstrated a significant linear correlation (AP: p = n.s.; ML: p < 0.05; SI: p < 0.05). In the frequency range 0.5–1.0 MHz, BUA exhibited a significant linear increase in the AP and ML directions, but not the SI direction (AP: p < 0.05; ML: p < 0.01; SI: p = n.s.). In contrast, in the frequency range 1.0–2.0 MHz, BUA exhibited a highly significant increase with density in the SI direction, but no significant change in the AP and ML directions (AP: p = n.s., ML: p = n.s., SI: p < 0.001).