MRI-Based Patient-Specific Left Ventricular Model to Determine the Effects of Trabeculae Carneae on the Diastolic and Systolic Functions

Introduction Trabeculae carneae are irregular structures that cover the endocardial surfaces of both ventricles of human heart and account for a significant portion of the ventricular mass.However,the role of trabeculae carneae in left ventricular(LV)function is not well understood.Previous reports suggested that trabeculae help squeeze blood from the apical region during systole[1].Our recent study suggests that trabeculae carneae hypertrophy and fibrosis contribute to increased LV stiffness in patients with diastolic heart failure,and severing free-running trabeculae carneae may improve diastolic compliance of the LV[2].Objective To understand the role of trabeculae carneae in the left ventricular diastolic and systolic functions using anatomically detailed patient-specific finite element models of the human LV.Methods(1)Image acquisition An explanted human heart was collected from a 63 year old female donor with a history of stroke and congestive heart failure within 24 hours postmortem from South Texas Blood and Tissue Center(San Antonio,TX).The heart was de-identified in accordance with Institutional Review Board(IRB)requirements and informed consent for research was obtained from the donor’s family.Three-dimensional MRI scanning was conducted on a 3T(128 MHz)MRI system(TIM Trio,Siemens Medical Solutions),comprised of a superconducting magnet with a 60 cm diameter accessible bore,when the heart was submerged in a saline filled plastic container.(2)Finite element analysis Three distinct LV models were derived from the MR images.The first model was the intact trabeculated model(TM)which contained all trabeculae carneae and papillary muscles.This high-resolution anatomically detailed 3D model of the LV was segmented from 2D MR images in DICOM format using Mimics(Materialise NV,Leuven,Belgium).The second model was the papillary model(PM),in which the papillary muscles remain intact but most of the trabeculae carneae were excluded in the smoothing process.The third model was the smooth model(SM)in which the trabeculae carneae and papillary muscles were excluded during image segmentation.Finite element(FE)models of the TM,PM and SM were created by meshing 3D reconstructions of the acquired MR images using tetrahedral elements(ICEM,Ansys Inc.,Canonsburg,PA).The mesh size was selected after a pilot study on mesh sensitivity.The passive cardiac muscle was characterized as a hyperelastic,incompressible,transversely isotropic material with a Fung exponential strain energy function.The material constants were determined by matching the end-diastolic pressure-volume relationship with the empirical Klotz relation[3].A rule-based myocardial fiber algorithm was adopted to generate the myofiber directions [4].The active contraction(i.e.,systolic contraction)was modeled by the time varying'Elastance'active contraction model.The contractile parameter Tmax was determined and calibrated so that the FE predicted ejection fraction(EF)of TM matched the EF of a normal human heart at the specified end-systolic pressure[3].The analysis of the TM,PM,and SM models were implemented using the open-source finite element package FEBio(www.febio.org).In all models,the rigid body motion was suppressed by constraining the base from moving in all directions.The end-diastolic and end-systolic pressure-volume relationships(EDPVR and ESPVR)were obtained and characterized by an exponential function and the slope,respectively.Results Our simulation results showed that independent of the material model,the EDPVR curve shifts to the right in PM and SM compared to TM.However,the ESPVR curve may shift to the right or left in PM compared to TM,while shifting tothe right in SM for all material models.EDPVR was steeper in TM compared to PM and SM;however,ESPVR was found to be steeper in PM than in TM and SM.The predicted parameters of EDPVR and ESPVR showed lower average exponential term in PM and SM compared to TM,indicating a significant improvement in the compliance and global diastolic function of less trabeculated LV models(P<0.01).Similarly,the higher average elastance EEs and lower volume intersect in PM compared to TM,suggests that mild cutting of trabeculae carneae slightly improves the global systolic function of the LV(P=0.89).However,cutting all trabeculae carneae and papillary muscles in SM had a significant adverse effect on the global systolic function(P<0.01).Discussion and conclusions Most patient-specific LV studies in the literature have used smoothed ventricular geometries.We used high resolution MRI to capture the endocardial details of the LV.Though reproducing very fine trabeculae carneae was restricted by the MRI resolution,our results demonstrated the importance of considering endocardial structures,i.e.papillary muscles and trabeculae carneae,in the assessment of LV global function in patient-specific computational LV models.The present work is consistent with the observation that diastolic performance improved after severing trabeculae carneae due to a reduction in LV stiffness[2].Furthermore,our results also suggest that severing trabeculae carneae(without affecting papillary muscle)may improve LV systolic function.Our model results are consistent with experimental measurements using ex vivo rabbit heart perfusion [5].This improvement would be greater in hypertrophic hearts because trabeculae carneae are also hypertrophic and more fibrotic.Left ventricular hypertrophy is often associated with heart failure with preserved ejection fraction(HFpEF).There is no effective treatment for HFpEF,which is characterized by impaired diastolic relaxation due to increased LV stiffness.Our results indicate that trabecular cutting could be an effective treatment for HFpEF.

Trabecular Plate Loss and Deteriorating Elastic Modulus of Femoral Trabecular Bone in Intertrochanteric Hip Fractures

Osteoporotic hip fracture is associated with significant trabecular bone loss,which is typically characterized as low bone density by dual-energy X-ray absorptiometry(DXA)and altered microstructure by micro-computed tomography(μCT).Emerging morphological analysis techniques,e.g.individual trabecula segmentation(ITS),can provide additional insights into changes in plate-like and rod-like trabeculae,two major micro-structural types serving different roles in determining bone strength.Using ITS,we evaluated trabecular microstructure of intertrochanteric bone cores obtained from 23 patients undergoing hip replacement surgery for intertrochanteric fracture and 22 cadaveric controls.Micro-finite element(μFE)analyses were performed to further understand how the abnormalities seen by ITS might translate into effects on bone strength.ITS analyses revealed that,near fracture site,plate-like trabeculae were seriously depleted in fracture patients,but trabecular rod volume was maintained.Besides,decreased plate area and rod length were observed in fracture patients.Fracture patients also showed decreased elastic moduli and shear moduli of trabecular bone.These results provided evidence that in intertrochanteric hip fracture,preferential loss of plate-like trabeculae led to more rod-like microstructure and deteriorated mechanical competence adjacent to the fracture site,which increased our understanding of the biomechanical pathogenesis of hip fracture in osteoporosis.

Micro-CT分析跟骨内骨小梁分布及结构特征

背景:跟骨位于足的后下部,受力较大。跟骨外形复杂且不规则,外周有较薄的皮质骨包绕,内部充满大量的骨小梁,探讨骨小梁的微观结构、走行及分布特征有助于提高对跟骨骨折的认识。目的:采用微计算机断层扫描仪(Micro-CT)扫描跟骨标本获得其影像资料,对其内部骨小梁结构进行分析,探讨跟骨内骨小梁的形态、分布及结构特征。方法:采用Micro-CT连续扫描干燥成人跟骨标本,扫描后获得影像图像,将其以DICOM格式存储。导入影像资料到Hiscan Analyzer软件,显示清晰完整的成人跟骨矢状面、冠状面、水平面的图像,逐层观察骨小梁的走行,依据骨小梁走行特点将跟骨矢状面分为6个部分,在以7 mm为标准的相同厚度下,每个部分选择1个49 mm2等面积的兴趣区,三维重建后获得跟骨及骨小梁的立体微观结构,二值化后运用软件计算感兴趣区域内骨小梁的体积分数、表面密度、骨小梁厚度、骨小梁间隙和骨小梁数量参数。结果与结论:①跟骨表面皮质层很薄,内部充满大量骨松质,在Gissane角的骨皮质明显增厚;②跟骨上部的骨小梁体积分数大于跟骨下部前端、中和三角区、跟骨下后部、跟骨结节部、跟骨底部,跟骨结节部的骨小梁体积分数大于跟骨下部前端、中和三角区、跟骨下后部、跟骨底部;跟骨结节部的骨小梁表面密度大于跟骨下部前端、中和三角区、跟骨底部,跟骨上部、跟骨下后部的骨小梁表面密度大于中和三角区;跟骨上部的骨小梁厚度大于跟骨结节部;中和三角区的骨小梁间隙大于跟骨上部、跟骨结节部;跟骨结节部的骨小梁数量大于中和三角区;③中和三角区主要分布杆状骨小梁,骨小梁表面密度最小、体积分数较小、骨小梁间隙最大;该部位骨质较疏松,受到高冲击力时抗压缩能力差,骨小梁最先发生断裂,是易发生骨折的部位。

下颈椎椎弓根的显微形态学特征

背景:下颈椎椎弓根是脊柱后柱的主要应力部位,对人体重心稳定的维持及减轻振荡有重要意义,目前对其内部骨小梁特征、椎弓根与关节突及椎体的连接部位的特征研究鲜有报道,迫切需要了解椎弓根的精细解剖结构及其各部分关系和功能。目的:通过Micro-CT扫描下颈椎椎骨标本以观测椎弓根显微解剖学形态,测量和分析正常下颈椎椎弓根内骨小梁的微结构和形态计量学参数以评估颈椎的安全性能。方法:选取31套干燥成人下颈椎骨骼标本C3-C7进行Micro-CT扫描,通过对椎弓根内骨小梁感兴趣区的勾选与重建,观察下颈椎椎弓根内骨小梁的形态特征及走形方向,检测骨微细结构参数,并分析比较C3-C7椎弓根骨微细结构的差异性。结果与结论:①Micro-CT图像显示下颈椎椎弓根的蜂窝样骨小梁呈复杂的网状微结构,靠近皮质骨的骨小梁呈板层状,结构相对致密,并向前方椎体部和向后方关节突椎板部延伸;板状骨小梁向髓腔伸展转化为网状结构,再转化为杆状骨小梁,髓腔内杆状骨小梁分布稀疏;②骨小梁各形态参数统计结果显示,C4、C5椎弓根的骨小梁骨体积分数高于C7(P<0.05),C7椎弓根的骨表面积/骨体积高于C3、C4、C6(P<0.05),C7椎弓根的骨小梁骨表面密度高于C3、C4、C5、C6(P<0.05),C7椎弓根的骨小梁厚度高于C3、C4、C5(P<0.05),左侧椎弓根骨小梁的骨表面积/骨体积、骨表面密度比较大于右侧(P<0.05);③该文总结了C3-C7微结构变化规律,其中C7椎弓根的负荷能力及应力较差,该区发生损伤的风险较高。

Influence Mechanism of the Trabecular and Chamfer Radii on the Three-point Bending Properties of Trabecular Beetle Elytron Plates

To improve the mechanical properties of Trabecular Beetle Elytron Plates(TBEPs,a type of biomimetic sandwich structure inspired by the beetle elytron)under transverse loads,three-point bending tests are performed to investigate the influence of the trabecular and chamfer radii of the core structure on the mechanical performance of TBEPs manufactured by 3D printing technology.The results show that the three-point bending performance of TBEPs can be improved by setting reasonable trabecular and chamfer radii;however,excessive increases in these radii can cause a decline in the mechanical performance.For the reason,these two structural parameters can enhance the deformation stiffness of the whole structure and the connection property between the core and skin,which is also the mechanical reason why Prosopocoilus inclinatus beetle elytra have thick,short trabeculae with a large chamfer radius.However,when these radii increase to a certain extent,the cracks are ultimately controlled between two adjacent trabeculae,and the failure of the plate is determined by the skin rather than the core structure.Therefore,this study suggests a reasonable range for trabecular and chamfer radii,and indicates that TBEPs are better suited for engineering applications that have high compression requirements and general bending requirements.

不同灰度阈值的骨质疏松性骨小梁3D模型的力学性能差异

背景:骨质疏松患者多伴有脆性骨折的发生,国内外很少利用3D骨小梁仿真模型压缩实验来阐明其发生发展机制。目的:建立不同灰度阈值的骨质疏松性骨小梁3D模型,通过机械压缩实验比较分析其骨小梁微结构、力学性能的差异。方法:选择1例老年骨质疏松性单侧股骨颈骨折患者,女性,69岁,采用GE64排螺旋CT对双侧髋关节自髋臼至股骨中上段行CT扫描,借助Micro-CT重建,建立不同灰度阈值的三维骨小梁模型,获取其微结构参数,通过机械压缩实验得出相关力学性能参数并进行比较。结果与结论:(1)成功建立不同灰度阈值的骨质疏松性骨小梁3D模型,随着灰度阈值的增加,骨体积分数降低,骨表面积密度降低,骨小梁数量减少,骨小梁分离度增大;(2)随着骨小梁灰度阈值的增加其弹性模量降低,可以看出屈服强度、压缩强度及最大抗压力也呈现出这样的趋势;(3)提示不同灰度阈值所打印的3D骨小梁仿真模型,其骨微细结构参数及力学性能参数有明显差异,可为骨质疏松脆性骨折的发生发展机制在材料力学方面提供一种新的研究方法。

以不同方式处理肌小梁和乳头肌后基于心脏MRI所测中国健康成人左心室结构和功能参数的差异

目的基于心脏MRI(CMRI)以不同方式处理肌小梁和乳头肌(TPM)后观察中国健康成人左心室结构和功能的差异。方法回顾性分析168名中国健康成人,包括男105名、女63名的CMRI资料。分别采用标准(将TPM包含于血池内)和精细(将TPM包含在心肌组织中)方法测量左心室舒张末期容积(EDV)、收缩末期容积(ESV)、每搏输出量(SV)及射血分数(EF),对比其间左心室结构和功能参数的差异。随机选取50名受试者,由2名观察者以相同方法测量上述参数,分析观察者间测量结果的一致性及其变异系数(CV)。结果相比标准方法测量结果,以精细方法所测全部、男性及女性受试者的EDV、ESV和SV均较小,而EF较大(P均<0.001);经体表面积校正后,以2种方法所获全部、男性及女性受试者EDV、ESV和SV差异均有统计学意义(P均<0.001)。观察者间以标准方法所获左心室EDV、ESV和EF的一致性均极好(ICC=0.90~0.94)、CV为3.10%~5.29%,以精细方法所测上述参数的一致性为好至极好(ICC=0.85~0.95),CV为4.36%~9.74%。结论基于CMRI以不同处理TPM方式所测中国健康成人左心室结构和功能参数存在差异。

IDEAL-IQ联合Micro-CT定量评估兔1型糖尿病骨髓脂肪含量和骨小梁微结构相关性的研究

目的 采用定量非对称回波的最小二乘估算法迭代水脂分离序列(iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation sequence, IDEAL-IQ)联合计算机显微断层扫描(micro computed tomography, Micro-CT)技术评估兔1型糖尿病腰椎骨髓脂肪含量和骨小梁微结构相关性。材料与方法 将16只雄性日本大耳白兔随机分为糖尿病组(n=8)和对照组(n=8),糖尿病组采用四氧嘧啶造模。在造模成功后第0、4、8、12、16周通过IDEAL-IQ定量评估兔腰椎骨髓脂肪含量。在第16周采用Micro-CT及组织病理学检查对兔腰椎骨小梁微结构进行定量评估。不同时间点腰椎IDEAL-IQ脂肪分数差异比较采用重复测量方差分析;同一时间点组间脂肪分数、Micro-CT骨小梁形态计量学参数、组织病理学参数差异比较采用独立样t检验或Mann-Whitney U检验;采用Pearson相关系数评估骨髓脂肪分数与骨小梁形态计量学参数、组织病理学参数相关性。结果 糖尿病组骨髓脂肪含量随时间变化呈上升趋势,且差异存在统计学意义(P<0.05),而对照组各时间点脂肪含量差异无统计学意义(P>0.05);糖尿病组与对照组腰椎骨髓脂肪分数在第16周差异有统计学意义(59.987±4.859 vs. 51.015±8.469,P<0.05);第16周糖尿病组骨体积、总表面积、骨表面积、骨表面积总体积比、骨小梁数量均低于对照组,而骨小梁分离度高于对照组,差异有统计学意义(P<0.05);组织病理学结果显示,与对照组相比,第16周糖尿病兔腰椎骨髓脂肪细胞数量(32.875±11.051 vs. 71.667±13.125, P<0.01)增加,而骨小梁数量(11.375±1.506vs.4.333±1.211, P<0.01)与骨小梁面积(0.927±0.071vs.0.312±0.100, P<0.01)明显减少;IDEAL-IQ脂肪分数与组织病理学脂肪细胞计数呈正相关关系(r=0.539 95%CI:0.012~0.832),与骨小梁模式因子、骨小梁结构模型指数、骨小梁分离度呈轻中度正相关关系,与骨矿物质密度、总体积、骨体积、骨体积分数、总表面积、骨表面积、骨表面积体积比、骨表面积总体积比、骨小梁数量呈轻至中度负相关关系。结论 1型糖尿病腰椎骨髓脂肪含量与骨小梁微结构变化存在相关性,IDEAL-IQ联合Micro-CT的多模态定量影像技术有望为1型糖尿病提供全面的骨髓微环境评估策略。

跟骨及其周围结构的临床解剖学研究

目的 :探讨跟骨及其周围结构的解剖学特点及其在跟骨骨折治疗中的意义。方法 :3 0侧干燥跟骨标本分 3组分别从冠状面、矢状面和水平面剖开 ,观察跟骨骨小梁排列。解剖 13例 2 6侧成人足部标本 ,观察跟骨周围的肌腱、血管、神经走行 ,以及关节囊和韧带的附着。对其中 3侧新鲜足标本分别以红黑墨水灌注胫后动脉及腓动脉 ,观察跟骨及其足部皮肤的血供状况。结果 :跟骨骨小梁的分布特点为内、后、上致密 ,外、前、下稀疏。胫后动脉主要供应跟骨前下部骨质和足底前 2 /3皮肤 ,腓动脉主要供应跟骨后上方骨质和足跟底部皮肤 ,胫前动脉则供应跟骨中央和足背绝大部分皮肤。结论 :应根据跟部皮肤的血供选择手术切口。载距突和跟骨结节可作为跟骨骨折内固定的固定点。

盐制对杜仲治疗去卵巢大鼠骨质疏松症影响的研究

目的研究杜仲及其盐制品对去卵巢大鼠骨质疏松症的治疗作用,并探讨盐制对其治疗作用的影响。方法 40只SD雌性大鼠分为伪手术组、模型对照组、杜仲生品治疗组和杜仲盐制品治疗组,除假手术组施行假手术外,其余均行手术彻底摘除卵巢,术后4周开始杜仲生品及盐制品水提液灌胃给药(4.0 g/kg·d),实验过程称体质量,连续给药12周后,颈动脉取血,测定血钙(S-Ca)、血磷(S-P)含量,ELISA试剂盒双抗体夹心法测定血清碱性磷酸酶(ALP)、骨钙素(OCN)、雌二醇(E2)含量;动物处死后剥取完整子宫称重,采用HE染色法进行子宫病理学检查,剥离双侧股骨,双能X射线衍射法测定大鼠股骨骨密度。HE染色法观察股骨骨小梁形态和成骨细胞数量,micro-CT扫描观察股骨骨小梁微体系结构。结果杜仲生品及盐制品能有效抑制去卵巢所致的大鼠体重增加,升高血清钙、雌二醇的含量,降低血磷、碱性磷酸酶和骨钙素的含量。增加大鼠股骨骨密度,改善股骨骨小梁微体系结构,增加股骨骨小梁成骨细胞数量,且长期用药对子宫无明显刺激作用。结论杜仲生品及盐制品对于大鼠去卵巢所引起的骨质疏松症有良好治疗作用,且盐制品效果优于生品。

壮骨肾宝防治肾上腺皮质激素所致大鼠骨质疏松的实验研究

本研究采用３月龄ＳＤ雄性大鼠２４只，随机分为对照组（Ⅰ组）、激素组（Ⅱ组）和预防组（Ⅲ组）。Ⅱ组喂醋酸泼尼松２次／周；Ⅲ组除喂泼尼松外，还同时喂壮骨肾宝。３个月后对３组大鼠胚骨上段的骨片用图像分析仪进行测算和分析。激素组与对照组比较，由于骨吸收大于骨形成，出现骨小梁面积和数量减少，骨小梁之间的空隙增加。出现明显的骨质疏松症状。用壮骨肾宝预防的激素组，骨吸收率受到明显抑制，新骨形成增加，因而骨量明显增加。本研究提示壮骨肾宝能预防激素所致的骨质疏松。

大鼠去势后对颌骨和股骨骨小梁结构的影响

目的 观察雌激素低下时骨质疏松对颌骨和股骨骨小梁结构的影响。方法 切除SD雌性大鼠双侧卵巢 8周后处死大鼠 ,取颌骨和股骨标本 ,对组织切片进行骨组织形态计量学分析。结果 去势后大鼠颌骨、股骨均呈疏松化改变 ,实验组骨小梁面积比、骨小梁平均宽度、骨小梁平均间隔宽度与对照组具有显著性差异 (P <0 .0 5 ) ,股骨的变化更为明显。结论 骨质疏松对全身骨组织和口腔骨组织的影响具有差异性 ,颌骨骨吸收小于全身骨组织的吸收。

司坦唑醇对类固醇性大鼠骨质疏松的预防作用

目的：探讨司坦唑醇对类固醇性大鼠骨质疏松的预防作用。方法：用泼尼松建立类固醇性大鼠骨质疏松模型，用大鼠胫骨近端作骨组织形态计量学观察，并取血液作各项有关的生化指标检查。结果：与对照组相比，类固醇模型组的大鼠胫骨近端出现明显的骨质疏松症。而司坦唑醇防治组对类固醇性骨质疏松有明显的对抗作用。肝肾功能检测未发现明显的毒副反应。

骨质疏松症对松质骨骨小梁应力与微损伤关系的影响

目的应用显微CT和微有限元分析评估微损伤、微骨折骨小梁的应力、应变,探讨骨质疏松症对骨小梁应力和微损伤、微骨折之间关系的影响。方法通过显微CT扫描健康和骨质疏松人体髋臼松质骨,构建松质骨块三维微有限元模型,在无摩擦的位移边界条件下模拟松质骨块的单轴压缩实验,通过非线性微有限元分析得到在不同表观应变下骨小梁的应力、应变、微损伤和微骨折。结果 0.05%-0.50%表观应变下,健康和骨质疏松松质骨未损伤骨小梁的应力在50 MPa以下,微损伤骨小梁应力在110 MPa以上。健康松质骨骨小梁的平均应力相对较高,骨质疏松松质骨骨小梁最高应力值相对较高。健康和骨质疏松松质骨骨小梁均出现微损伤,健康松质骨骨小梁微损伤较多,骨质疏松骨骨小梁出现微骨折。结论在表观小应变范围内,健康松质骨骨小梁能承受更高的应力,出现较多的微损伤,而骨质疏松松质骨高应力骨小梁群内出现微骨折。

联合高分辨率MRI和micro-CT评价桃红四物汤对兔股骨头坏死的修复作用

目的建立激素性股骨头坏死(SIONFH)家兔模型,联合高分辨率MRI和micro-CT评价桃红四物汤(THSWD)对于SIONFH微观骨性结构破坏的修复作用。方法将25只新西兰兔随机分为3组:正常组5只、模型组和中药组(桃红四物汤组)各10只,采用内毒素(LPS)联合甲强龙(MPS)的方法制备激素性股骨头坏死模型,中药组给予0.3 g/kg桃红四物汤混悬液灌胃,正常组和模型组灌服等体积超纯水。实验第8周分别进行股骨头部3.0 T高分辨率磁共振影像仪高分辨率MRI检查,对股骨头部苏木精-伊红染色病理检测及micro CT检测。结果1)高分辨率MRI中模型组股骨头内可见低信号带;中药组股骨头外形趋于正常,股骨头内近骨骺处有小块低密度区,大部分骨组织灰度值正常。模型组和正常组相比,结构参数前者ROE值增加,ROE/NR比例增加,中药组与模型组相比,ROE值减少,ROE/NR比例减少,差异有显著性(P<0.05)。2)经苏木精-伊红染色中,模型组可见部分骨小梁断裂,骨细胞核固缩,骨小梁空骨陷窝,骨髓细胞坏死,差异有显著性(P<0.05),中药组可见成骨活动仍较为活跃,骨小梁形态较好。3)在micro-CT中,模型组与正常组相比,前者BV/TV、Conn.D.、SMI、Tb.N、Tb.Th、值降低,BS/BV、Tb.Sp增高。中药组中,BS/BV、Tb.Sp显著低于模型组,Conn.D.、SMI、Tb.N增高,差异有显著性(P<0.05),ROI三维重建可见模型组骨小梁紊乱,可见普遍断裂,骨质较少;中药组相对而言骨质改善,骨小梁有局部性修复。结论桃红四物汤能促进兔SIONFH模型的微观骨性结构修复和生物力学环境改善。

阿魏酸钠治疗糖皮质激素性骨质疏松的实验研究

目的探讨阿魏酸钠对于大鼠糖皮质激素性骨质疏松症的治疗作用。方法 3月龄Wistar大鼠随机均分5组:对照组、模型组、治疗组(阿魏酸钠低、中、高剂量组)。动物处死前进行钙黄绿素双荧光标记。采用骨组织形态计量学方法测量胫骨的静态参数、动态参数、骨组织细胞和生长板变化。结果①静态参数:与对照组相比,模型组骨小梁面积百分数、骨小梁厚度、骨小梁数量明显减少,骨小梁分离度增大;与模型组相比,阿魏酸钠中、高剂量组骨小梁面积百分数、骨小梁厚度、骨小梁数量明显增加,骨小梁分离度明显减小。低剂量组骨小梁厚度明显增加。②动态参数:与对照组相比,模型组标记周长百分数、骨转化率、骨表面新骨形成率明显增大;与模型组相比,中、高剂量组新骨年形成率增加。③骨组织细胞:与对照组相比,模型组单位骨小梁面积成骨细胞数量、破骨细胞数量以及成骨细胞周长占骨小梁周长百分率均明显增加。与模型组相比:各个实验组均没有明显变化。④生长板:与对照组相比,模型组生长板宽明显增大;与模型组相比,各实验组生长板退行细胞高度、生长板宽均没有明显变化。结论阿魏酸钠对糖皮质激素性骨质疏松的治疗作用主要体现在增加骨量和改善骨小梁结构,并促进骨形成。

去势骨质疏松症大鼠模型防治效果的参数比较

目的 评价防治骨质疏松症大鼠模型药物疗效的各项指标。方法 采用卵巢切除术建立骨质疏松症预防和治疗大鼠模型 ,分别灌喂阿仑膦酸钠和埃本膦酸钠 ,持续处理 6个月。以骨密度、骨生化标志物、骨矿含量、骨生物力学和骨组织形态学方面的参数为指标 ,评价它们的价值。结果 两组大鼠模型用药后 ,各部位的骨密度明显升高。评价药物疗效时 ,敏感度、特异度、准确度最高的是全身骨密度和骨小梁面积。用药大鼠的股骨最大弯曲载荷、骨挠度、股骨干重、灰重、骨钙含量虽有不同程度的增高 ,血清骨钙素有一定程度的下降 ,但与对照组相比基本均无统计学意义。结论 全身骨密度是评价防治骨质疏松症药物疗效的最佳指标 ,骨切片计算骨小梁面积也是评价防治骨质疏松症药物疗效的敏感指标。

仿生双相磷酸钙生物陶瓷支架的Micro-CT评价

[目的]体外用MicroCT(Microcomputedtomography)图像对仿生双相磷酸钙生物陶瓷支架的三维结构进行计算机重建和评价。[方法]犬股骨头的松质骨样本行MicroCT扫描,提取图像信息;三维凝胶叠层成型法制备出具有仿骨小梁结构的双相磷酸钙仿生生物陶瓷支架。随后用MicroCT对支架扫描,以三维结构参数对支架和松质骨样本作三维评价和比较。三维参数包括骨体积分数(BoneVolumeFraction,BVF,BV/TV)、骨表面积体积比(Bonesurface/bonevolumeratio,BS/BV)、骨小梁厚度(Trabecularthickness,TbTh)、骨小梁数目(Trabecularnumber,TbN)、骨小梁间隙(Trabecularspacing,TbSp)、结构模型指数(StructureModelIndex,SMl)和各向异性程度(degreeofanisoropy,DA)。[结果]与犬股骨头松质骨样本相比,用本方法制备出的BCP支架具有相似的三维空间结构,二者的BV/TV、TbTh、TbN无显著差别(P>0.05)。小梁结构呈板状模型。[结论]本研究制备的BCP多孔支架的小梁具有一定的取向性,力学强度和良好的适于血管长入的空间结构。

鸸鹋股骨头坏死两种修复方式骨显微结构变化的比较

目的比较鸸鹋股骨头坏死不同造模方式股骨头骨显微结构的差异。方法成年鸸鹋15只,分为3组,每组5只,均以右侧股骨头为研究对象:第1组为正常组,不做处理;第2组为冷冻建立模型组,通过液氮和射频冷热交替的方式建立股骨头坏死塌陷模型;第3组为乙醇建立模型组,通过局部注射无水乙醇的方式建立股骨头坏死塌陷前模型。造模成功后分别取各个实验动物右侧股骨标本,股骨标本近端行显微计算机断层摄影扫描,并进行3组标本骨显微结构参数的比较和统计分析。结果所有鸸鹋术后无明显感染征象,未发生实验动物异常死亡。与正常组相比,冷冻建立模型组骨小梁改建后骨矿物量(P=0.015)和骨小梁间距(P=0.001)明显减少,骨体积比(P=0.036)、骨表面积/体积比(P=0.032)和骨小梁数目明显增加(P=0.002),骨小梁厚度差异无统计学意义(P=0.060)。与正常组相比,乙醇建立模型组骨小梁改建后骨矿物量明显增高(P=0.001)、骨小梁厚度(P=0.003)和骨表面积/体积比(P=0.022)明显增加,骨小梁间距(P=0.001)和骨体积比(P=0.001)明显减少,骨小梁数目差异无统计学意义(P=0.143)。与乙醇建立模型组比较,冷冻建立模型组的骨矿物量(P=0.001)、骨小梁厚度(P=0.001)和骨体积比(P=0.001)明显减低,骨表面积/体积比(P=0.022)和骨小梁数目(P=0.003)明显增高,骨小梁间距差异无统计学意义(P=0.398)。结论不同修复方式可造成重建后股骨头负重区骨小梁结构及骨密度的不同,产生的重建骨小梁骨质量也不同。