The mechanical properties of cancellous bone in the proximal tibia of ovariectomized rats.

The "mature rat model" is an effective and often-used surrogate for studying mechanisms and characteristics of estrogen-deficient osteopenia. The purpose of this study was to extend our understanding of this animal model to include the mechanical properties of cancellous bone in the proximal tibia. Female Sprague-Dawley rats were divided into two groups (n=13 each) at 14 weeks of age: an ovariectomized group (OVX) and a sham-operated control group (sham). The study terminated after a duration of 5 weeks. Specimens 2 mm long were cut from the proximal tibial metaphysis just below the growth plate and tested using two methods: (1) "whole-slice" compression, in which the entire specimen is loaded between two larger flat platens and (2) "reduced-platen" compression (RPC), which uses platens sized and aligned to load only the cancellous bone in the center of the sample. Three-point bending tests also were conducted on the femur. The short duration of estrogen deficiency yielded only minimal differences (< 10%) in femoral cortical bone but dramatic reductions (approximately 60%) in cancellous bone properties as determined by the RPC method. Ultimate stress was 7.23 MPa +/- 1.97 MPa for OVX versus 18.1 MPa +/- 5.21 MPa for sham; and elastic modulus was 252 MPa +/- 104 MPa for OVX versus 603 MPa +/- 180 MPa for sham. These changes in mechanical properties are similar in many respects to the dramatic effects reported in histomorphometric studies. For the whole-slice method, differences in mechanical properties between the two groups were not as large because the test directly loads both cancellous and cortical bone, and the latter is not affected as severely by estrogen deficiency. In this case, ultimate stress and elastic modulus were only 30% (or less) lower for the OVX group.     

Bone mineral density,mechanical properties,and trabecular orientation of cancellous bone within humeral heads affected by advanced shoulder arthropathy

The mechanical properties of cancellous bone in the humeral head are increasingly interesting due to the increased popularity of stemless prosthetic fixation in the cancellous bone of the metaphysis. Age or pathology-related systemic osteoporosis, inactivity, or pathology of the shoulder joint may influence the primary bonding of implants that rely on good cancellous bone quality. We assessed the bone mineral density (BMD) and anisotropy using micro-computed tomography (micro-CT) (0.04 mm voxel size) and correlated the results with indentation load/displacement response. Resected parts of humeral heads (from patients undergoing total shoulder replacement, n = 18) were used as probes. The region of interest was defined as 2 mm medial from the resection plane, presuming that it mirrored the bone quality lateral to the resection plane. The indentation tests were performed with a large probe (diameter 10 mm) in a single destructive loading procedure. The BMD and trabecular orientation were determined by micro-CT. Our results showed a correlation between the BMD and the slope of the load/displacement curve. Furthermore, the trabeculae were predominantly oriented orthogonal to the joint surface. In conclusion, the predominant factor determining the bone quality and mechanical resistance to pressure appears to be the BMD, while trabecular orientation could not be related to load/displacement response. Statement of clinical significance: Bone quality predominately determines the mechanical properties of cancellous bone. This might be crucial when prosthetic implants need to be anchored in metaphyseal bone. Therefore, clinical decision-making processes should also include local BMD measurements.     

鹿瓜多肽对去卵巢大鼠骨密度、股骨生物力学及松质骨中BMP2表达的影响

目的鹿瓜多肽（松梅乐）注射液肌注对去卵巢大鼠骨密度、股骨生物力学及松质骨中BMP2表达的影响。方法将8月龄未经产雌性二级SD大鼠30只，随机分为假手术组（SHAM）组、去势组（OVX）、去势＋鹿瓜多肽（OVX＋CCP）组。OVX＋CCP组大鼠术后第1天开始给药，术后20周处死各组大鼠．应用双能X线吸收仪（DEXA）测量各组大鼠股骨粗隆、股骨干中点及第3～5腰椎中点的骨密度（BMD）；应用INSTRON1195电子拉伸试验机检测股骨生物力学性能；利用免疫组织化学染色及图像分析方法对各组大鼠松质骨切片图像进行灰度分析，观察鹿瓜多肽注射液对OVX大鼠松质骨中BMP2表达的影响。结果（1）OVX与SHAM组比较，灰度值降低明显（P〈0．01），而OVX＋CCP组灰度值较去势组降低（P〈0．01），表明OVX大鼠松质骨中骨小梁周围及髓腔中BMP2表达阳性细胞数明显多于SHAM组；而OVX＋CCP组骨小梁周围及髓腔内BMP2表达阳性细胞数多于去势组，且染色加深。（2）与SHAM组相比，OVX组股骨近端、股骨干、腰椎BMD明显降低（P〈0．01）；OVX＋CCP各部位BMD高于去势组（P〈0．01），但未达到SHAM组水平（P〈0．01）；（3）与SHAM比较，去势组大鼠股骨最大载荷、桡度、最大应力、弹性模量均明显下降（P〈0．01），治疗组上述指标高于去势组（P〈0．01），接近对照组水平（P〉0．05）。结论鹿瓜多肽注射液可以抑制和延缓骨质疏松的形成，对雌激素缺乏引起的骨质疏松具有预防作用。     

黄芪多糖治疗对去卵巢诱导骨质疏松大鼠骨密度、骨量和骨代谢的影响

目的探索黄芪多糖对去卵巢大鼠骨量和骨代谢以及BMP-2/Smads信号通路的影响。方法30只雌性SD大鼠进行去卵巢手术或假手术。正常饲养12周后被分为黄芪多糖组(ASNT组)、对照组(CON组)和去卵巢组(OVX组),其中黄芪多糖组每天给予400 mg/kg黄芪多糖治疗。通过骨密度、骨代谢指标、Micro-CT以及WB检测评估ASNT对骨质疏松症大鼠骨量、骨代谢以及BMP-2/Smads信号通路的影响。结果经过12周治疗,ASNT组大鼠骨密度较OVX组显著增加(P<0.05);ASNT治疗12周可以降低血清ALP和OC水平,增加血钙含量,增加股骨骨密度。经过12周治疗,ASNT组大鼠骨体积分数(BV/TV)、表面积体积分数(BS/TV)、骨小梁厚度(Tb.Th)、骨小梁数目(Tb.N)较OVX组显著增加;而骨小梁间隙(Tb.Sp)较OVX组显著降低,差异比较有统计学意义(P<0.05)。WB结果表明OVX大鼠骨组织的BMP-2/Smsds信号通路受到抑制;ASNT可以通过上调BMP-2、p-Smad1和p-Smad5的表达显著激活BMP-2/Smsds信号通路传导。结论研究表明ASNT对去卵巢大鼠骨密度和骨量具有保护作用,可能和激活BMP-2/Smads信号通路有关。     

Slow rebound of cancellous bone after mainly steroid-induced osteoporosis in ovariectomized sheep

OBJECTIVES: A sheep model of osteoporosis suitable for implant testing for osteoporotic fractures was evaluated with regard to normalization of hormonal status and possible rebound of bone mineral density subsequent to the termination of steroid application. DESIGN: Osteoporosis was induced in 10 aged, female white alpine sheep. The sheep underwent ovariectomy, were kept in open, single-box husbandry, received a vitamin D(3) restricted diet, and a total dose of 2000 mg methylprednisolone (4 single doses of 500 mg at 3-week intervals). After 12 weeks, osteoporosis induction was discontinued, and bone mineral density was monitored for another 28 weeks. Eight healthy sheep served as controls for final measurements. MAIN OUTCOME MEASUREMENTS: The bone mineral density of cancellous bone in both distal radii was monitored using peripheral quantitative computed tomography. Cortisone level was determined at 3-week intervals until week 21. Bone structural parameters were measured in biopsies of the lumbar vertebra 6 and the right iliac crest using micro CT. RESULTS: The linear rate of bone loss during osteoporosis induction was 1.75% per week. Rebound of cancellous bone mineral density started between 6 and 11 weeks after the end of steroid treatment with a linear coefficient of 0.22% per week. Whereas structural changes in the iliac crest revealed significant differences at the end of the study, the values of L6 showed only slight changes. The level of basal cortisone dropped below detection limit during induction but recovered to physiological values 6 weeks after the end of steroid administration. In 2 animals, massive loss of weight and in 4 animals alopecia disseminata occurred. CONCLUSIONS: Because the rebound of bone mineral density after the end of steroid administration is significantly slower than the initial decrease, this opens a sufficient time window for testing of implants for osteoporotic fractures. The significantly changed structural parameters at the end of the study also suggest osteoporosis like conditions during testing.     

Glucocorticoid effects on changes in bone mineral density and cortical structure in childhood nephrotic syndrome

The impact of glucocorticoids (GC) on skeletal development has not been established. The objective of this study was to examine changes in volumetric bone mineral density (vBMD) and cortical structure over 1 year in childhood nephrotic syndrome (NS) and to identify associations with concurrent GC exposure and growth. Fifty‐six NS participants, aged 5 to 21 years, were enrolled a median of 4.3 (0.5 to 8.1) years after diagnosis. Tibia peripheral quantitative computed tomography (pQCT) scans were obtained at enrollment and 6 and 12 months later. Sex, race, and age‐specific Z‐scores were generated for trabecular vBMD (TrabBMD‐Z), cortical vBMD (CortBMD‐Z), and cortical area (CortArea‐Z) based on >650 reference participants. CortArea‐Z was further adjusted for tibia length‐for‐age Z‐score. Quasi‐least squares regression was used to identify determinants of changes in pQCT Z‐scores. At enrollment, mean TrabBMD‐Z (?0.54 ± 1.32) was significantly lower (p = 0.0001) and CortBMD‐Z (0.73 ± 1.16, p < 0.0001) and CortArea‐Z (0.27 ± 0.91, p = 0.03) significantly greater in NS versus reference participants, as previously described. Forty‐eight (86%) participants were treated with GC over the study interval (median dose 0.29 mg/kg/day). On average, TrabBMD‐Z and CortBMD‐Z did not change significantly over the study interval; however, CortArea‐Z decreased (p = 0.003). Greater GC dose (p < 0.001), lesser increases in tibia length (p < 0.001), and lesser increases in CortArea‐Z (p = 0.003) were independently associated with greater increases in CortBMD‐Z. Greater increases in tibia length were associated with greater declines in CortArea‐Z (p < 0.01); this association was absent in reference participants (interaction p < 0.02). In conclusion, GC therapy was associated with increases in CortBMD‐Z, potentially related to suppressed bone formation and greater secondary mineralization. Conversely, greater growth and expansion of CortArea‐Z (ie, new bone formation) were associated with declines in CortBMD‐Z. Greater linear growth was associated with impaired expansion of cortical area in NS. Studies are needed to determine the fracture implications of these findings. © 2013 American Society for Bone and Mineral Research.     

PM 2.5对去卵巢骨质疏松症大鼠骨密度和生物力学性能的影响

目的 探讨PM 2.5对去势致骨质疏松症大鼠腰椎（L3~5）、右侧股骨骨密度及左侧股骨骨生物力学特性的影响。方法 将3周龄雌性SD大鼠（SPF级）适应生长一周后随机分为假手术组、模型对照组和PM 2.5低、中、高剂量组,行气道滴注PM 2.5混悬液或生理盐水,滴注5个月后将模型对照组和PM 2.5各剂量组通过切除大鼠双侧卵巢建立绝经后骨质疏松症模型,假手术组仅切除卵巢周围约1 g的脂肪组织。继续气管滴注至第9个月末,其间分别测定去势后滴注第7、9个月末各组腰椎（L3~5）、右侧股骨骨密度(bone mineral density,BMD)数值,处死大鼠后取左侧股骨进行三点弯曲试验。结果 气管滴注7个月后, 各组大鼠腰椎（L3~5）及右侧股骨 BMD 比较差异无统计学意义 (P>0.05)。滴注9个月后, PM 2.5各剂量组大鼠腰椎及右侧股骨 BMD 明显低于模型对照组,且PM 2.5各剂量组之间呈现一定的剂量关联趋势,中、高剂量组BMD降低趋势明显,差异有统计学意义 (P<0.05)。此外,从骨生物力学角度分析,与假手术组相比,模型对照组、PM 2.5低剂量组的弹性载荷、极限载荷、弹性模量均下降,且差异有统计学意义( P＜0.05) ;与模型对照组比较,PM 2.5各剂量组的股骨弹性载荷、极限载荷和弹性模量降低( P＜0. 05),下降趋势与BMD一致,高剂量组下降最为显著。结论 PM 2.5加速了去势大鼠的骨密度降低,造成骨生物力学破坏,与PMOP的严重程度相关,具体机制有待探讨。     

Constitutive relationships of fabric, density, and elastic properties in cancellous bone architecture.

The hypothesis that trabecular morphology can predict the elastic properties of cancellous bone has only partly been verified and no predictive analytical model is currently available. Such models are becoming increasingly relevant as the resolution levels of three-dimensional scanning techniques approach the size of trabeculae. This study took advantage of micro-finite-element methods and tested the aforementioned hypothesis in normal cancellous bone material collected at six anatomical locations from 56 individuals. Numerical analysis was based on high-resolution three-dimensional computer reconstructions of cancellous bone specimens from which the complete elastic characteristics and trabecular morphology, represented by three different fabric measures (the mean intercept length and two volume-based ones), were calculated. Each fabric measure was analyzed individually using the tensorial relationships derived by Cowin (Mech Mater 4:137-147; 1985). Models for both stiffness and compliance entries were developed. The models based on stiffness entries could explain 93.4%-95.6% of the variance, whereas those based on compliance entries could explain 89.2%-89.4%. When using the former model, the MIL (mean intercept length measure) performed slightly better than the two volume-based measures, VO (volume orientation) and SVD (star volume distribution), with 23% less remaining variance. The high correlations found strongly support the hypothesis and increase the hope that, on the basis of information on trabecular morphology, it will be possible to obtain considerably better estimates of bone quality in vivo compared with the rough two-dimensional density measurements used today.     

Compressive mechanical properties of human cancellous bone after gamma irradiation.

The effect of gamma irradiation on the mechanical properties of human bone was examined. Specimens of cancellous bone were cut from the proximal epiphyseal region of fresh-frozen tibiae and divided into control and irradiated groups according to anatomical region. The irradiated groups were exposed to 10,000, 31,000, 51,000, or 60,000 gray (1.0, 3.1, 5.1, or 6.0 megarad). The specimens were tested in compression to failure to determine failure stress, strain to failure, and elastic modulus. Failure stress and elastic modulus were found to be proportional to the square of the density and were normalized with respect to this property. Significant differences in normalized failure stress (p less than 0.001) and normalized elastic modulus (p = 0.003), when compared with the values for matched control specimens, were found only for the specimens that had been irradiated with 60,000 gray (6.0 megarad).     

Water content measured by proton-deuteron exchange NMR predicts bone mineral density and mechanical properties.

NMR was used to measure matrix water content in normal and hypomineralized cortical bone. Water content showed an inverse relationship with mineral content, suggesting it could serve as a surrogate measure for the bone's degree of mineralization. INTRODUCTION: So far, true bone mineral density (DMB; degree of mineralization of bone) can not be measured nondestructively. MATERIALS AND METHODS: Here, a new technique combining 1H nuclear magnetic resonance (NMR) spectroscopy and deuterium isotope exchange was used to measure water content in cortical bone from two groups of rabbits: a control group and a group fed a low-phosphorus (P) diet to induce hypomineralization of the bone matrix. RESULTS: NMR-derived water content was higher in the P-depleted group and showed an inverse relationship with mineral content (measured gravimetrically and by 31p NMR). Hypomineralized bone was found to be weaker than normal bone as demonstrated by mechanical testing. More importantly, the data showed a strong inverse correlation between water content and bone mechanical properties, which indicates that water content could be predictive of the bone's mechanical competence. CONCLUSIONS: Water content could potentially serve as a surrogate measure for the bone's degree of mineralization, and this technique could be used to study other disorders of mineral homeostasis known to alter the mineralization state of the matrix. Although the method presented here is not suitable for in vivo measurements of bone water content, the authors have previously shown that 1H NMR images of bone can be acquired; thus, noninvasive quantification of bone water may be feasible.     

纤维蛋白胶复合BMP对去卵巢山羊骨密度和松质骨中OPG表达的影响

目的 了解纤维蛋白胶（Fibrin sealant,FS）复合BMP2局部成骨机制,为其临床应用提供实验依据.方法 将9只2岁雌性山羊施行卵巢切除术,以每个山羊桡骨远端为一个实验单位,共18个单位,随机分为：生理盐水组（NS）、纤维蛋白胶组（FS）、实验组（FS＋BMP2）,每组6个单位.术后6个月,分别在各组桡骨远端一次性注射生理盐水、纤维蛋白胶和纤维蛋白胶复合BMP2.注射5周后,应用双能X线吸收仪（DEXA）测量各组山羊桡骨远端的骨密度（BMD）;在桡骨远端取活组织,利用免疫组织化学染色及图像分析方法对组织切片进行图像分析,观察纤维蛋白胶复合BMP2对去势山羊松质骨骨保护素（OPG）表达的影响.结果 ①与NS组比较FS＋BMP2组桡骨远端BMD明显升高（P＜0.01）,FS组BMD变化不明显（P＞0.05）;FS＋BMP2组BMD明显高于FS组和NS组（P＜0.01）.②FS＋BMP2组灰度值明显低于NS组和FS组（P＜0.01）;NS组和FS组灰度值差别不明显（P＞0.05）.结论 局部注射纤维蛋白胶复合BMP2具有高效的骨诱导活性,对局部骨质疏松骨折具有预防作用.     

Effects of genistein on vertebral trabecular bone microstructure,bone mineral density,microcracks, osteocyte density,and bone strength in ovariectomized rats

Until now, the effects of phytoestrogen on bone in both women and ovarian hormone-deficient animal models of osteoporosis have remained uncertain. We have aimed here to investigate the effect of genistein (GEN) on trabecular bone quality in ovariectomized (OVX) rats. Forty 7-month-old female Sprague-Dawley rats were randomly divided into the following four groups: OVX, sham-operated (SHAM), treated with 17beta-estradiol (EST, 10 microg x kg(-1) x day(-1)), and GEN (5 mg x kg(-1) x day(-1)). At 15 weeks postoperation, the compressive test was performed on the L5 vertebral body; additionally, microcomputed tomography (micro-CT) assessment was performed to estimate the bone mineral density (BMD) and microstructure parameters of the L6 vertebral body. After fatigue damage testing, the L6 vertebral body was bulk-stained in 1% basic fuchsin and embedded in methylmethacrylate. The L4 vertebral body was embedded in methylmethacrylate for dynamic histomorphometry analysis without staining. Mounted bone slices were used to measure microcrack parameters, empty osteocyte lacuna density (e.Lc.Dn), and osteocyte density (Ot.N/T.Ar). Maximum loading (ML) and Ot.N/T.Ar were significantly lower in the OVX group than in the other groups. E.Lc.Dn was significantly decreased in GEN and EST groups compared to the OVX group. ML was significantly decreased in the GEN group compared to the SHAM group. Microcrack density, microcrack surface density, and microcrack length were significantly increased in the OVX group compared to the other groups. Mineral apposition rate was significantly decreased in the OVX group compared to the SHAM and GEN groups. Bone formation rate was significantly decreased in the OVX group compared to other groups. There were no significant differences with regard to mineralizing surface among the four groups. Volumetric BMD at organ was significantly lower in OVX, EST, and GEN groups than in the SHAM group. Bone mineral content was significantly lower in the OVX group than in the SHAM group. Bone volume fraction and trabecular number were significantly decreased in OVX, EST, and GEN groups compared to the SHAM group. Structure model index was significantly lower in the SHAM group than in OVX, EST, and GEN groups. Trabecular separation was significantly increased in the OVX group compared to SHAM and EST groups. There were no significant differences with regard to the trabecular thickness (Tb,Th) between SHAM, GEN, and OVX groups. Tb.Th was significantly lower in the EST group than in the SHAM group. Connectivity density (Conn.D) was significantly lower in the OVX group than in SHAM and GEN groups, and Conn. D was significantly lower in the EST group than in GEN. In conclusion, the present study demonstrates that GEN preserved the biomechanical quality of the trabecular bone regardless of the microstructure and BMD.     

Bone mineral density,ultrasound velocity,and broadband attenuation predict mechanical properties of trabecular bone differently

Measurement of areal bone mineral density (BMD(areal)), broadband ultrasound (US) attenuation (BUA), and speed-of-sound (SOS) are widely used ways to perform clinical assessment of bone quality. In this study, bovine (n = 37) and human (n = 32) trabecular bone was investigated in vitro and in vivo to reveal relationships between mechanical properties, mineral density, and US parameters BUA and SOS. To fulfill these aims, clinical US and dual-energy X-ray absorptiometry (DXA) techniques, as well as dynamic and destructive mechanical testing, were utilized. BUA correlated positively and linearly with BMD(areal) only in human calcaneus of low or moderate density (r = 0.849, n = 32, p < 0.01). When calcaneal areas with high BMD(areal) were included in the analysis, however, the in vivo study revealed that the BUA-BMD(areal) relationship could be described by a second-order polynomial fit (r(2) = 0.618, n = 408). In high-density human or bovine bone, the BUA-bone density relationship was negative. In the in vitro assessment, BUA correlated linearly and negatively with volumetric BMD (BMD(vol)) (r = -0.540, n = 29, p < 0.01) and with storage modulus, as measured at 1 Hz (r = -0.505, n = 28, p < 0.01). A weak positive correlation was found between BUA and mechanical loss tangent (r = 0.322, n = 28, p < 0.1). SOS correlated strongly positively with BMD(vol) (r = 0.888, n = 29, p < 0.01), as well with storage modulus (r = 0.649, n = 28, p < 0.01). In contrast, SOS correlated negatively with loss tangent (r = -0.417, n = 28, p < 0.05). When tested dynamically in the frequency range of 0.01-22.7 Hz, bovine trabecular bone was only slightly viscoelastic. In summary, the most accurate parameters for measuring storage modulus and strength of bovine trabecular bone were SOS and BMD(vol), respectively. BUA failed to predict the mechanical properties of high-density trabecular bone. In vivo mapping of the calcaneus revealed the importance of standardized and reproducible localization of the measurement site for the validity of BUA values.     

定量CT对股骨头松质骨骨密度的测量

目的探讨利用定量CT(quantitative computed tomography,QCT)中"3D Spine Exam Analysis"软件分析模块测量股骨头松质骨的骨密度的可重复性,以及患者双侧股骨头松质骨骨密度的差异性。方法回顾性研究330名(女性239人,男性91人)受试者的股骨头松质骨骨密度,对其中因各种原因仅可获得一侧髋关节图像的受试者149人进行可重复性研究;对其余的受试者181人进行双侧股骨头松质骨骨密度的差异性研究。利用QCT Pro软件中"3D Spine Exam Analysis"软件分析模块将股骨头划分为上、中、下3个层面:靠近股骨颈上部皮质、经股骨颈中心、靠近股骨颈下部皮质,并对各个层面进行测量。结果2名不同操作者测量同一股骨头的相同层面松质骨骨密度值的差异无统计学意义(P_上=0. 148 0. 05,P_中=0. 05,P_下=0. 0970. 05)。同一患者双侧股骨头相对应层面的松质骨骨密度之间具有良好相关性。在上层,两侧股骨头的松质骨骨密度之间的差异无统计学意义(P_上=0. 4450. 05);而在中层与下层,两侧股骨头的松质骨骨密度之间的差异有统计学意义(P_中=0. 0000. 05,P_下=0. 0000. 05)。结论利用QCT中"3D Spine Exam Analysis"软件分析模块进行股骨头松质骨的骨密度测量具有较好的可重复性。患者双侧股骨头不同层面松质骨的骨密度具有良好的相关性,并且左侧股骨头的中层与下层的松质骨骨密度显著大于右侧。     

龟地散与钙剂对去卵巢大鼠骨重、骨密度、骨强度的影响

使用补肾健骨中药龟地散对切除卵巢的雌性大鼠进行不同剂量的药物治疗,并与模型对照组和钙剂组进行比较.实验结果表明:龟地散显著提高模型对照组大鼠骨密度值(P<0.05)和骨矿含量(P<0.05),从而抑制骨矿溶解和丢失.与模型对照组相比,龟地散明显增加骨质疏松大鼠的骨重(P<0.01),并且对大鼠的骨长、骨直径、骨面积和体重也有一定的影响.龟地散还具有显著提高大鼠骨强度(P<0.01)等方面的作用.单纯补钙除骨强度明显改变外,其他如骨矿质、骨密度等多种指标均未有明显改变.     

龟地散与钙剂对去放巢大鼠骨重,骨密度,骨强度的影响

使用补肾健骨中药龟地散对切除卵巢的雌性大鼠进行不同剂量的药物治疗,并与模型对照组和钙剂组进行比较。实验结果表明：龟地散显提高模型对照组大鼬有密度值（Ｐ〈０．０５）和骨矿含量（Ｐ〈０．０５）,从而抑制骨矿溶解和丢失。与模型对照组相比,龟地散明显增加骨质疏松大鼠的骨重（Ｐ〈０．０１）,并且对大鼠的骨长、骨直径、骨面积和体重也有一定的影响。龟地散还具有显提高大鼠骨强度（Ｐ〈０．０１）等方面的作用。单     

电针对去卵巢大鼠骨密度及生物力学的影响

目的研究电针对去卵巢骨质疏松模型大鼠骨密度(BMD)、生物力学的影响。方法选取60只雌性SD大鼠,随机分为空白组、模型组、假手术组、药物组、电针组,每组12只。空白组不做任何处理;假手术组只暴露双侧卵巢但不切除;其余3组行双侧切卵巢法建立骨质疏松模型大鼠。造模13周后开始治疗,电针组取"肾俞"、"脾俞"、"三阴交"、"足三里",每次电针刺激15 min(断续波,2 Hz,1.0m A)并灌服与药物组相同体积的蒸馏水,每日1次,连续治疗5 d,间隔2 d,20 d为1个疗程,共3个疗程;药物组大鼠以戊酸雌二醇水溶液(0.02 mg/mL,1 mL/100 g体质量)灌胃,疗程同电针组;空白组不予处理,常规饲养;模型组、假手术组大鼠灌服与药物组相同体积的蒸馏水,疗程同电针组。治疗结束后麻醉处死大鼠,分离股骨和第4腰椎,双能X射线骨密度检测仪检测股骨和腰椎BMD;三点弯曲法和压缩法检测股骨和腰椎生物力学。结果与假手术组相比,模型组大鼠股骨和第四腰椎离体BMD、股骨和第四腰椎的最大载荷及弹性模量均显著性降低(P0.01);与模型组相比,电针组、药物组大鼠股骨和第四腰椎离体BMD、股骨和第四腰椎的最大载荷及弹性模量均显著性升高(P0.01);电针组、药物组大鼠股骨和第四腰椎离体BMD、股骨和第四腰椎的最大载荷及弹性模量均显著性低于假手术组(P0.01)。结论针刺能有效增加大鼠骨密度,阻止骨量降低,减缓骨力学的退变,增强骨强度,对绝经后骨质疏松症具有一定的治疗作用。     

Mutual associations among microstructural,physical and mechanical properties of human cancellous bone

Previous studies have shown that low-density, rod-like trabecular structures develop in regions of low stress, whereas high-density, plate-like trabecular structures are found in regions of high stress. This phenomenon suggests that there may be a close relationship between the type of trabecular structure and mechanical properties. In this study, 160 cancellous bone specimens were produced from 40 normal human tibiae aged from 16 to 85 years at post-mortem. The specimens underwent micro-CT and the microstructural properties were calculated using unbiased three-dimensional methods. The specimens were tested to determine the mechanical properties and the physical/compositional properties were evaluated. The type of structure together with anisotropy correlated well with Young's modulus of human tibial cancellous bone. The plate-like structure reflected high mechanical stress and the rod-like structure low mechanical stress. There was a strong correlation between the type of trabecular structure and the bone-volume fraction. The most effective microstructural properties for predicting the mechanical properties of cancellous bone seem to differ with age.     

去卵巢后大鼠不同部位的骨组织计量学与骨密度研究

目的 观察大鼠去除卵巢后不同部位骨的骨组织计量学参数与骨密度以及两之间的相关性。方法 分别进行卵巢去除和伪手术，56d时处死大鼠，取离体胫骨，股骨测量骨密度与组织学参数%Tb.Ar,Tb.Th,Tb.N。结果 OVX后5d时，股骨远端和胫胫骨近端大部分骨组织计量学参数下降；全股骨和股骨远端1/3处骨密度降低；股骨部分骨组织计量学参数与骨密度测量值之间存在正相关性且差异有显性。结论 切除大鼠卵巢56d时，大鼠骨组织计量学参数下降显，骨密度测量以股骨较为敏感，骨组织计量学与骨密度测量值之间的相关性以股骨明显。     

藤黄健骨胶囊对去卵巢骨质疏松大鼠骨密度和骨代谢的影响

目的研究藤黄健骨胶囊对骨质疏松大鼠骨密度和骨代谢的影响。方法采用去卵巢法制备大鼠骨质疏松症模型,灌胃藤黄健骨胶囊干预,灌胃1个月后取材。称重法检测各组大鼠的体重,酶联免疫吸附(ELISA)试剂盒检测血清骨钙素(osteocalcin,BGP)和抗酒石酸酸性磷酸酶(tartrate resistant acid phosphatase,trACP)含量;双能X线吸收测量仪测量获得骨密度(bone mineral density,BMD);AG-IX生物力学万能实验机检测最大载荷和断裂载荷;HE染色法观察股骨的病理形态学变化。结果与假手术组比较,模型组大鼠体重明显升高,血清抗酒石酸酸性磷酸酶明显升高(P0.05);而模型组大鼠血清骨钙素明显降低,骨密度明显减少,最大载荷和断裂载荷明显减少(P0.05);模型组骨小梁结构不完整、丢失、断裂严重。与模型组相比,藤黄健骨胶囊组大鼠血清骨钙素的含量和抗酒石酸酸性磷酸酶的活性得到纠正(P0.05),股骨的骨微观参数骨密度均得到了良好地修复,骨生物力学参数中最大载荷、断裂载荷得到了明显修复(P0.05),骨小梁排列规则,数目增多、增宽。结论藤黄健骨胶囊能够修复去卵巢骨质疏松症大鼠股骨微观结构破坏和股骨生物力学性能的下降,提示藤黄健骨胶囊具有良好的抗骨质疏松作用。