丹参酮IIA缓解大鼠心肌梗死后左心室重构的作用及其机制研究

摘要 目的：探讨丹参酮IIA（T-IIA）对于缓解大鼠心肌梗死（MI）后左心室重构（LVR）的作用及其机制。方法：选取SD雄性大鼠80只,通过结扎左前降支（LAD）建立MI大鼠模型。将大鼠随机分为8组,假手术组未结扎LAD,其余各组均结扎LAD;除假手术组和MI组腹腔注射生理盐水外,其余各组分别给予T-IIA、脂多糖（LPS）和TAK-242治疗。HE和马松（Masson）三色染色评估MI大小、组织病理改变和纤维化程度。末端dUTP镍末端标记（TUNEL）染色观察心肌细胞凋亡情况。采用反转录定量聚合酶链反应(RT-qPCR)和蛋白免疫印迹试验检测Toll样受体4（TLR4）、髓样分化蛋白88（MyD88）和核因子κB（NF-κB）的表达水平。结果：T-IIA能改善MI大鼠心功能,可降低MI大鼠心脏体积,改善心脏形态,减轻MI大鼠的组织病理学改变,并有效减轻MI和心肌纤维化。T-IIA抑制MI大鼠的TLR4/MyD88/NF-κB信号通路,且能有效减少MI大鼠梗死边缘区心肌细胞凋亡。结论：T-IIA通过抑制TLR4/MyD88/NF-κB信号通路的激活,改善心脏形态、功能和病理组织学变化,有效减轻MI的严重程度,预防LVR。     

基于TLR4/MyD88/NF-κB信号通路探讨安肠汤联合艾灸治疗肝郁脾虚证腹泻型肠易激综合征的疗效及其机制

摘要 目的：基于Toll样受体4（TLR4）/髓样分化因子88（MyD88）/核因子-κB（NF-κB）信号通路探讨安肠汤联合艾灸治疗肝郁脾虚证腹泻型肠易激综合征（IBS）的疗效及其机制。方法：采用随机数字表法,将广州中医药大学第一附属医院在2019年4月~2022年12月期间收治的108例腹泻型IBS患者分为对照组（常规药物联合艾灸治疗,n=54）和研究组（对照组基础上接受安肠汤治疗,n=54）。对比两组疗效、中医证候总积分、IBS症状严重程度问卷（IBS-SSS）评分、肠屏障功能指标、TLR4/MyD88/NF-κB信号通路相关信使核糖核酸（mRNA）表达水平。结果：研究组的临床总有效率高于对照组（P<0.05）。两组治疗后中医证候总积分、IBS-SSS评分下降,且研究组低于对照组（P<0.05）。两组治疗后肠脂肪酸结合蛋白（IFABP）、D-乳酸及二胺氧化酶（DAO）下降,且研究组低于对照组（P<0.05）。两组治疗后TLR4、MyD88、NF-κB mRNA表达下降,且研究组低于对照组（P<0.05）。结论：安肠汤联合艾灸治疗肝郁脾虚证腹泻型IBS患者,可有效改善临床症状和肠屏障功能,疗效较好,可能与调节TLR4/MyD88/NF-κB信号通路有关。     

香草醛对新生大鼠缺氧缺血性脑损伤的神经保护作用研究

摘要 目的：探讨香草醛对新生大鼠缺氧缺血性脑损伤(HIBI)的神经保护作用及机制。方法：参考Rice-Vannucci方法建立HIBI大鼠模型。HIBI大鼠建模后立即腹腔注射20 mg/kg（HIBI+20Van组）或40 mg/kg（HIBI+40Van组）的香草醛,每隔12 h给药,连续7 d。然后评估大鼠的神经行为及脑组织中IL-1β、IL-6和TNF-α的水平。对BV2小胶质细胞进行氧糖剥夺/复氧(OGD/R)处理,并用20 μM香草醛培养。通过Western blot及免疫荧光检测HMGB1、NF-κB p65、SIRT1、MyD88和TLR4的表达水平。通过乳酸脱氢酶（LDH）释放测定试剂盒测定用不同BV2细胞培养基处理的原代神经元的LDH释放。结果：与HIBI组比较,HIBI+20Van组和HIBI+50Van组新生大鼠的前肢悬吊时间和旷场得分均升高,脑组织中的IL-1β、IL-6和TNF-α的水平均降低。香草醛均升高了HIBI大鼠和OGD/R处理的BV2细胞质中的SIRT1的表达水平,降低了TLR4、MyD88和HMGB1的表达水平及细胞核中NF-κB p65的表达水平（P<0.05）。香草醛降低了原代神经元的LDH释放量（P<0.05）。结论：香草醛通过调节SIRT1/HMGB1/TLR4/MyD88/NF-κB信号通路抑制HIBI引起的神经炎症,从而提高HIBI大鼠的神经功能。     

基于TLR4MyD88信号通路观察粪菌移植对DSS诱导小鼠溃疡性结肠炎干预作用机制

摘要 目的：探讨粪菌移植（fecal microbiota transplantation,FMT）对葡聚糖硫酸钠（dextran sodium sulfate, DSS）诱导小鼠溃疡性结肠炎（ulcerative colitis,UC）干预作用及其炎症相关的分子机制。方法：30只昆明小鼠采用DSS喂养建立结肠炎小鼠模型并随机分为模型组、FMT低剂量组和FMT高剂量组,另取10只作为对照组。FMT低剂量组、FMT高剂量组自造模后第1 d开始分别给予8 g/kg、15 g/kg粪菌剂量灌肠处理,灌肠体积0.2 mL。对照组和模型组给予等体积生理盐水灌肠处理。分别在实验第1、7、14及21 d称量小鼠体重。实验结束后处死小鼠,取出结直肠,观察各组小鼠结直肠形态变化并通过HE染色观察病变程度。ELISA检测小鼠结直肠组织匀浆液上清中肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）、白细胞介素-6（interleukin 6, IL-6）、白细胞介素-4（interleukin 4, IL-4）和白细胞介素-10（interleukin 10, IL-10）的表达变化;免疫组化法和RT-qPCR分别检测结直肠组织中核因子κB-P65亚基 (nuclear factor-κB P65, NF-κB P65)蛋白和mRNA的表达情况;Western blotting检测结直肠组织中Toll 样受体4 (Toll-like receptor 4,TLR4)、髓样分化因子 88(myeloid differentiation factor 88,MyD88)的蛋白表达情况。结果：对照组相比,造模小鼠在第6 d起至第14 d体重明显减轻,差异具有统计学意义（P<0.05）;与模型组相比,FMT低、高剂量组小鼠第10 d起至第14 d体重明显减轻,FMT高剂量组小鼠体重升高更加明显,差异具有统计学意义（P<0.05）;与对照组相比,模型组小鼠结直肠组织中TNF-α、IL-6、NF-κB P65 mRNA和蛋白阳性表达、TLR4、MyD88 蛋白表达均显著升高(P<0.05),IL-4、IL-10表达显著下降（P<0.05）;FMT高剂量组IL-4、IL-10较模型组显著升高,其余指标均显著下降（P<0.05）。结论：FMT可通过抑制TLR4/MyD88/NF-κB信号通路缓解炎症反应,发挥对UC的治疗作用。     

基于HMGB1/TLR4/NF-κB信号通路探讨忍冬苷对脓毒症肝损伤大鼠的影响

摘要 目的：基于高迁移率族蛋白B1（HMGB1）/Toll样受体4（TLR4）/核因子κB（NF-κB）信号通路探讨忍冬苷对脓毒症肝损伤大鼠的影响。方法：60只雄性SD大鼠随机分为模型组、对照组、阳性对照组（地塞米松10 mg/kg）、忍冬苷低剂量（7.5 mg/kg）、忍冬苷中剂量（15 mg/kg）、忍冬苷高剂量（30 mg/kg）组,每组10只。采用盲肠结扎穿刺法建立大鼠脓毒症模型。实验结束后麻醉大鼠取血制备血清,检测血清中超氧化物歧化酶（SOD）活性和丙二醛（MDA）、白介素-6（IL-6）、肿瘤坏死因子-α（TNF-α）、白介素-10（IL-10）含量;分离肝组织称重,计算肝脏指数,一部分用于HE染色观察肝组织病理变化,一部分用于制备组织匀浆检测组织中肝功能指标谷丙转氨酶（ALT）、天冬氨酸转氨酶（AST）活性及HMGB1、TLR4、NF-κB蛋白表达。结果：与对照组比较,模型组大鼠血清中MDA、TNF-α、IL-6含量、肝脏指数以及肝组织中AST、ALT活性、HMGB1、TLR4、NF-κB蛋白表达显著增加（P＜0.05）,SOD活性与IL-10含量显著下降（P＜0.05）;且肝组织出现明显病灶,肝细胞水肿变性,大量炎性细胞浸润。与模型组比较,阳性对照组与忍冬苷各剂量组大鼠血清中MDA、TNF-α、IL-6含量、肝脏指数以及肝组织中AST、ALT活性、HMGB1、TLR4、NF-κB蛋白表达显著降低（P＜0.05）,SOD活性与IL-10含量显著升高（P＜0.05）;忍冬苷低、中剂量组仍可见病灶和水肿,但病变减轻;地塞米松组与忍冬苷高剂量组肝细胞结构趋于正常,未发现病灶。与阳性对照组比较,忍冬苷低、中剂量组大鼠血清中MDA、TNF-α、IL-6含量、肝脏指数以及肝组织中AST、ALT活性、HMGB1、TLR4、NF-κB蛋白表达显著升高（P＜0.05）,SOD活性与IL-10含量显著降低（P＜0.05）;忍冬苷高剂量组上述指标无显著差异（P＞0.05）。结论：忍冬苷通过下调HMGB1/TLR4/NF-κB信号通路的表达,抑制氧化应激,减轻炎症反应,改善肝功能,发挥对脓毒症肝损伤的保护作用。     

布地奈德混悬液对哮喘模型小鼠肺组织TLR4/MyD88/NF-κB通路的影响

摘要 目的：探究布地奈德混悬液对哮喘模型小鼠肺组织TOLL样受体4（toll-like receptor 4,TLR4）/髓样分化因子88（myeloid differentiation factor 88,MyD88）/核因子κB（nuclear factor-κB,NF-κB）通路的影响。方法：使用4 %鸡蛋清白蛋白与2 %的Al（OH3）共同致敏小鼠,建立咳嗽变异性哮喘小鼠模型40只,将模型大鼠分别使用低、中、高剂量（0.2、1.0、2.0 g/kg）布地奈德混悬液和孟鲁司特钠进行干预,1次/日连续干预14 d,于干预14 d时采集小鼠的支气管肺泡灌注液（bronchoalveolar lavage fluid,BALF）、气管及肺组织,对各组BALF中的白细胞（white blood cell,WBC）、嗜酸性粒细胞、血清γ干扰素（interferon-γ,IFN-γ）、白细胞介素-1β（interleukin-1β,Il-1β）、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)水平差异开展比较,对各组小鼠肺组织黏膜上皮增生程度评分、炎症细胞浸润程度评分、病变总评分差异,以及TLR4、MyD88、p65蛋白表达差异进行分析。结果：分析显示,布地奈德混悬液能够显著降低哮喘模型小鼠BALF中白细胞及嗜酸性粒细胞数量,同时还能够改善小鼠气管和支气管黏膜上皮增生与肺组织炎症细胞浸润状态,且干预后小鼠肺组织中的TLR4、MyD88、p65蛋白表达水平出现了明显的降低。结论：布地奈德混悬液对改善小鼠哮喘效果较好,其作用机制可能与该药能够调节TLR4、MyD88、p65蛋白表达,进而影响炎症和免疫反应进程有关。     

独一味胶囊对复发性口腔溃疡大鼠免疫功能和溃疡组织NF-κB炎症通路蛋白表达的影响

摘要 目的：探讨独一味胶囊对复发性口腔溃疡（ROU）大鼠免疫功能和溃疡组织核因子-κB（NF-κB）炎症通路蛋白表达的影响。方法：将60只SD大鼠随机分为正常组、模型组和独一味胶囊低、中、高剂量组,每组12只。除正常组外其余各组均采用免疫法建立ROU模型,建模8周后独一味胶囊低、中、高剂量组分别灌胃给予0.01 mg/mL、0.02 mg/mL、0.03 mg/mL独一味胶囊溶液治疗,正常组和模型组灌胃给予等量生理盐水,均连续治疗20 d。记录各组大鼠口腔溃疡数目、持续时间和口腔溃疡面积,采用酶联免疫吸附法检测血清白介素（IL）-1β、IL-6、肿瘤坏死因子-α（TNF-α）水平,流式细胞术检测外周血CD3⁺、CD4⁺、CD8⁺百分比并计算CD4⁺/CD8⁺比值,免疫印迹法检测口腔黏膜组织NF-κB p65、磷酸化NF-κB抑制蛋白α（p-IκBα）、IkappaB激酶α（IKKα）蛋白水平。结果：正常组未出现口腔溃疡,模型组、独一味胶囊低剂量组、独一味胶囊中剂量组、独一味胶囊高剂量组溃疡数目依次降低,持续时间依次缩短,溃疡面积依次缩小（P＜0.05）。模型组、独一味胶囊低剂量组、独一味胶囊中剂量组、独一味胶囊高剂量组、正常组IL-1β、IL-6、TNF-α、CD8⁺、NF-κB p65、p-IκBα、IKKα水平依次降低,CD3⁺、CD4⁺、CD4⁺/CD8⁺依次升高（P＜0.05）。结论：独一味胶囊能显著减少ROU大鼠口腔溃疡数目和面积,缩短愈合时间,且效果呈剂量依赖性,其机制可能与改善免疫功能和抑制NF-κB炎症通路有关。     

miR-29a对于膝关节骨性关节炎大鼠滑膜损伤中的保护作用研究

摘要 目的：探讨miR-29a对于膝关节骨性关节炎（KOA）大鼠滑膜损伤中的保护作用研究。方法：采用前交叉韧带横断法（ACLT）建立KOA大鼠模型。大鼠注射microRNA阴性对照和miR-29a。通过实时定量聚合酶链反应（RT-qPCR）检测KOA滑膜组织和滑膜细胞中miR-29a的表达。RT-qPCR和蛋白免疫印迹试验检测Toll样受体4/髓样分化蛋白88/核因子κB（TLR4/Myd88/NF-κB）信号通路相关蛋白的表达。检测KOA滑膜组织及滑膜细胞中炎症因子的表达水平。结果：KOA滑膜组织和滑膜细胞中miR-29a表达下调。上调miR-29a可抑制KOA大鼠滑膜细胞的炎症反应,促使KOA大鼠的TLR4/Myd88/NF-κB信号通路失活。结论：上调miR-29a可通过TLR4/Myd88/NF-κB信号通路失活化抑制KOA大鼠滑膜细胞炎症反应,从而保护滑膜损伤。     

儿童难治性肺炎支原体肺炎的危险因素及甲泼尼龙治疗的最佳剂量探讨

摘要 目的：分析儿童难治性肺炎支原体肺炎（RMPP）发生的危险因素,并探讨甲泼尼龙治疗的最佳剂量。方法：选择2018年7月~2021年8月期间我院收治的肺炎支原体肺炎（MPP）患儿183例。根据病情程度的不同将患儿分为普通肺炎支原体肺炎（GMPP）组（n=90）和RMPP组（n=93）,构建多因素Logistic回归方程分析儿童RMPP发生的危险因素。RMPP患儿均在常规治疗基础上应用甲泼尼龙治疗,并按照给药剂量的不同分为低剂量组[2 mg/（kg?d）]、中剂量组[3 mg/（kg?d）]和高剂量组[4 mg/（kg?d）],每组各31例,对比三组的疗效、临床症状消失时间和不良反应发生情况。结果：单因素分析结果显示：RMPP组发热天数长于GMPP组,特异性体质、肺外并发症患儿比例以及中性粒细胞百分比、降钙素原（PCT）、C反应蛋白（CRP）、乳酸脱氢酶（LDH）、白细胞介素-6（IL-6）水平高于GMPP组,淋巴细胞百分比低于GMPP组（P<0.05）。多因素Logistic回归分析结果显示：发热天数≥10 d、特异性体质、有肺外并发症、CRP≥24 mg/L、LDH≥250 IU/L、IL-6≥17 pg/mL是RMPP发生的危险因素（P<0.05）。高剂量组的临床总有效率高于中剂量组、低剂量组（P<0.05）,但中剂量组与低剂量组间临床总有效率无统计学差异（P>0.05）。高剂量组和中剂量组的咳嗽消失时间、体温恢复正常时间、肺部啰音消失时间和住院时间均短于低剂量组,且高剂量组上述时间均短于中剂量组（P<0.05）。低中高剂量三组间不良反应发生率比较无统计学差异（P>0.05）。结论：儿童RMPP的发生受到发热天数、特异性体质、肺外并发症以及CRP、LDH、IL-6水平等因素影响。应用4 mg/（kg?d）剂量甲泼尼龙治疗儿童RMPP疗效较好,可明显缩短患儿临床症状消失时间。     

miR-21在大鼠心肌细胞缺血再灌注损伤中的作用机制研究

摘要 目的：探讨微小RNA-21（miR-21）在大鼠心肌细胞缺血再灌注损伤中的作用机制。方法：选取50只SPF级Wistar大鼠并随机分为5组（n=10）,分别为对照组、模型组、模型+阴性对照组、模型+ miR-21组和模型+ miR-21抑制物组。通过结扎大鼠左冠前降支进行建模。建模成功后采用高频彩色超声诊断仪检查各组大鼠的心脏功能指标：心脏射血分数（EF）、左心室收缩期峰值压力（LVSP）、左室舒张末压（LVEDP）和缩短分数（FS）。检测各组大鼠心肌梗死面积和心肌细胞凋亡率。采用酶联免疫吸附试验（ELISA）测定各组心肌组织中肿瘤坏死因子-α（TNF-α）、白细胞介素-6（IL-6）和白细胞介素-10（IL-10）的含量。采用反转录聚合酶链式反应（RT-PCR）检测心肌组织中miR-21的表达水平。蛋白免疫印迹试验（Western Blot）检测各组大鼠心肌凋亡蛋白和TLR4/NF-κB表达水平。结果：模型组大鼠出现心肌梗死,提示建模成功,建模后大鼠心肌组织中miR-21的表达水平显著下降,提示miR-21可能具有保护心肌细胞的作用。建模成功后,EF、LVSP和FS下降,LVEDP升高,心肌细胞凋亡率显著升高,TNF-α和IL-6表达水平显著升高,IL-10显著下降,Bcl-2/Bax表达下降,Caspase-3表达升高,大鼠心肌细胞TLR4和NF-κB蛋白磷酸化表达水平升高,而模型+ miR-21组上述指标均得到改善。结论：大鼠心肌细胞缺血再灌注损伤导致miR-21表达降低,而过表达miR-21能有效抑制TLR4/NF-κB信号通路,降低大鼠心肌凋亡水平和炎症因子的释放,从而发挥保护心肌细胞的作用。     

峙峪遗址碎骨的研究

本文对峙峪遗址出土的近七百件碎骨进行了研究,结果表明这些碎骨主要是由于人工打击和动物啃咬造成的。在有人工打击痕迹的碎骨中,存在着打制骨器。在个别碎骨的局部表面有磨光的现象,推测是人类使用的结果。     

Effects of static magnetic fields on bone microstructure and mechanical properties in mice

All the living organisms originate, evolve and live under geomagnetic field (GMF, 20–70 µT). With rapid development in science and technology, exposure to various static magnetic fields (SMFs) from natural and man-made sources remains a public environmental topic in consideration of its probable health risk for humans. Many animal studies related to health effect have demonstrated that SMF could improve bone formation and enhance bone healing. Moreover, most of the studies focused on local SMF generated by rod-type magnet. It was difficult to come to a conclusion that how SMF affected bone metabolism in mice. The present study employed hypomagnetic field (HyMF, 500 nT), and moderate SMF (MMF, 0.2 T) to systematically investigate the effects of SMF with continuous exposure on microstructure and mechanical properties of bone. Our results clearly indicated that 4-week MMF exposure did not affect bone biomechanical properties or bone microarchitecture, while HyMF significantly inhibited the growth of mice and elasticity of bone. Furthermore, mineral elements might mediate the biological effect of SMF.     

Influence of Osteoprotegerin (OPG) on Resorption of Heterotopically Induced Ossicle

In this paper, the effect of osteoprotegerin (OPG) on slowing down the resorption process of heterotopically induced bone tissue is described. The induced ossicle is resorbed ex inactivitate. This system mimics osteoporosis in immobilised skeletal bones. Bone induction was achieved in BALB/c mice after the injection of the suspension of 3 x 10(6) HeLa cells into thigh muscle of animals immuno-suppressed by a single dose of hydrocortisone. To slow down the process of resorption we applied OPG and measured quantitatively the effect by weighing the mass of mineral deposited in the induced ossicle after hydrolysis of soft tissues surrounding the induced ossicles. As the effect of application of OPG more than 340-540% of bone mineral is found in the induced ossicles following nine applications of 0.05 mg OPG per mouse, every second day--in comparison to the control animals.     

2型糖尿病模型GK大鼠骨形态学和生物力学特点观察

目的观察2型糖尿病模型GK大鼠的骨代谢特点以及骨密度和骨生物力学特性的变化。方法采用雄性6月龄GK大鼠10只,以月龄、性别匹配的健康Wistar大鼠作为正常对照。颈静脉取血检测与骨代谢有关的生化指标。DXA法测定股骨和腰椎骨密度,并行股骨三点弯曲实验和腰椎压缩实验。甲基丙烯酸甲酯包埋胫骨干骺端以制备不脱钙骨切片。应用多媒体病理图像分析软件进行骨组织形态计量学分析。结果GK大鼠体重明显低于健康对照Wistar大鼠（P〈0.01）。与对照组相比,GK大鼠血清骨钙素水平明显降低[（4.97±0.49,6.75±0.71）μg/mL,P〈0.01],而抗酒石酸酸性磷酸酶活性明显升高[（17.92±5.23,8.31±2.69）U/L,P〈0.01],但血钙和血磷无明显变化（P〉0.05）;股骨和腰椎骨密度显著降低[（0.16±0.01,0.22±0.02;0.12±0.01,0.16±0.02）g/cm2,P〈0.01];骨强度和腰椎的弹性模量明显降低（P〈0.01）。骨形态学分析显示GK大鼠股骨长度和第五腰椎高度分别降低10.3%和9.5%（P〈0.01）,股骨和腰椎横截面积无明显变化（P〉0.05）。骨组织形态计量学分析显示,GK大鼠骨小梁体积、骨小梁厚度、类骨质表面和厚度明显降低[（15.72±1.18,19.13±1.13）%,（61.91±4.54,74.43±3.63）μm,（18.18±1.25,19.63±1.07）%,（3.68±0.48,4.34±0.35）μm,P〈0.01或0.05],动态参数如矿化表面、矿化沉积率和骨形成率也明显降低[（17.77±1.54,19.56±2.07）%,（1.07±0.22,1.35±0.16;0.20±0.03,0.26±0.04）μm/day,P〈0.05或0.01],而矿化延迟时间显著延长（2.66±0.56,2.12±0.35,P〈0.05）。结论非肥胖的GK大鼠表现有骨量减少和骨折危险性增加;2型糖尿病本身可干扰成骨细胞功能和活性而导致骨重建失衡。     

The Procurement Team as a Factor of Bone Allograft Contamination

We studied the effect of the procurement team on the risk of contamination in 270 large bone allografts retrieved from 53 non-living donors under strictly aseptic conditions.The overall contamination rate was 8.1%. When the procurement team was constituted by three or less members the contamination rate was 5.6%, while if there were four or more members the rate was 12.9%; this difference was significant in the statistical analysis.We conclude that a procurement team constituted by three or less trained members is a determinant factor in decreasing the bacterial contamination rate of bone allografts.     

Fresh-frozen human bone graft for repair of defect after adenomatoid odontogenic tumour removal

The aim of this paper was report the clinical, radiographic, and histological case of adenomatoid odontogenic tumour (AOT) in adolescent woman as well as present the reconstructive treatment of AOT using fresh-frozen human bone graft with guided bone regeneration. AOT is a benign, noninvasive lesion with slow but progressive growth. Biopsy and microscopic examination confirmed the presence of an AOT. Treatment was conservative and the prognosis was excellent. The patient has been followed-up for without recurrence. The use of fresh-frozen human bone graft can be a safe choice for reconstruction of the bone defects to treat AOT.     

Ability of bone graft substitutes to support the osteoprogenitor cells: An in-vitro study

AIM: To compare seven commercially available bone graft substitutes(BGS) in terms of these properties and without using any additional biological growth factors.METHODS: Porcine osteoprogenitor cells were loaded on seven commercially available BGS and allowed to proliferate for one week followed by osteogenic induction. Staining for live/dead cells as well as scanning electron microscopy(SEM) was carried out to determine viability and cellular binding. Further outcome measures included alkaline phosphatase(ALP) assays with normalisation for DNA content to quantify osteogenic potential. Negative and positive control experiments were carried out in parallel to validate the results.RESULTS: Live/dead and SEM imaging showed higher viability and attachment with β-tricalcium phosphate(β-TCP) than with other BGS(P 0.05). The average ALP activity in nmol/mL(normalised value for DNA content in nmol/μg DNA) per sample was 657.58(132.03) for β-TCP, 36.22(unable to normalise) for calcium sulphate, 19.93(11.39) for the Hydroxyapatite/Tricalcium Phosphate composite, 14.79(18.53) for polygraft, 13.98(8.15) for the highly porous β-Tricalcium Phosphate, 5.56(10.0) for polymers, and 3.82(3.8) for Hydroxyapatite.CONCLUSION: Under the above experimental conditions, β-TCP was able to maintain better the viability of osteoprogenitor cells and allow proliferation and differentiation(P 0.05).     

Osteoclast-osteoblast communication

Cells in osteoclast and osteoblast lineages communicate with each other through cell-cell contact, diffusible paracrine factors and cell-bone matrix interaction. Osteoclast-osteoblast communication occurs in a basic multicellular unit (BMU) at the initiation, transition and termination phases of bone remodeling. At the initiation phase, hematopoietic precursors are recruited to the BMU. These precursors express cell surface receptors including c-Fms, RANK and costimulatory molecules, such as osteoclast-associated receptor (OSCAR), and differentiate into osteoclasts following cell-cell contact with osteoblasts, which express ligands. Subsequently, the transition from bone resorption to formation is mediated by osteoclast-derived ‘coupling factors’, which direct the differentiation and activation of osteoblasts in resorbed lacunae to refill it with new bone. Bidirectional signaling generated by interaction between ephrinB2 on osteoclasts and EphB4 on osteoblast precursors facilitates the transition. Such interaction is likely to occur between osteoclasts and lining cells in the bone remodeling compartment (BRC). At the termination phase, bone remodeling is completed by osteoblastic bone formation and mineralization of bone matrix. Here, we describe molecular communication between osteoclasts and osteoblasts at distinct phases of bone remodeling.     

The biomechanical analysis of bone strength: A method and its application to platycnemia

Traditional methods of bone analysis (both metric and topographic) are restricted to external characters. Spacial distribution of material is, however, equally critical to an understanding of a bone's function. Dynamic testing to determine whole bone strength can only be performed on fresh specimens. Methods for the calculation of both bending and torsional strength of other specimens (such as preserved or fossil bones) are developed in this paper. In order to illustrate the methods, the functional significance of tibial shaft cross sectional variation is investigated.     

Variability of in vivo reference point indentation in skeletally mature inbred rats

Reference point indentation (RPI) has emerged as a novel tool to measure material-level biomechanical properties in vivo. Human studies have been able to differentiate fracture versus non-fracture patients while a dog study has shown the technique can differentiate drug treatment effects. The goal of this study was to extend this technology to the in vivo measurement of rats, one of the most common animal models used to study bone, with assessment of intra- and inter-animal variability. Seventy-two skeletally mature male Sprague-Dawley rats were subjected to in vivo RPI on the region between the tibial diaphysis and proximal metaphysis. RPI data were assessed using a custom MATLAB program to determine several outcome parameters, including first cycle indentation distance (ID-1st), indentation distance increase (IDI), total indentation distance (TID), first cycle unloading slope (US-1st), and first cycle energy dissipation (ED-1st). Intra-animal variability ranged from 13% to 21% with US-1st and Tot Ed 1st-L being the least variable properties and IDI the most highly variable. Inter-animal variability ranged from 16% (US-1st) to 25% (ED-1st and IDI). Based on these data, group size estimates would need to range from 9 to 18/group to achieve sufficient power for detecting a 25% difference in a two-group experiment. Repeat tests on the contralateral limb of a small cohort of animals (n=17) showed non-significant differences over 28 days ranging from −6% to −18%. These results provide important data on RPI variability (intra- and inter-animal) in rats that can be used to properly power future experiments using this technique.