rhPTH（1-34）治疗OVX大鼠骨质疏松延后效应的初步研究

目的观察重组人甲状旁腺激素（1-34）[rhPTH（1-34）]对卵巢摘除（OVX）大鼠骨质疏松症的治疗作用及停药后效应.方法应用双侧卵巢摘除方法建立模拟绝经后骨质疏松大鼠模型;给予皮下注射20μg/kg/d rhPTH（1-34）治疗8周,观察其骨量、骨生物力学、骨小梁形态计量及骨代谢相关血、尿生化指标,综合评价PTH对模型大鼠的治疗效果;同时观察停药8周后上述指标的变化.结果外源性PTH（1-34）治疗能显著增加模型大鼠的骨量、骨力学性能,改善骨微结构、增加骨转换.用药组的骨密度、股骨三点弯曲与腰椎压缩最大载荷、腰椎骨小梁百分面积显著高于对照组（P＜0.05～0.001）;血ALP（P＜0.05～0.01）与尿Pyd（P＜0.05）保持高水平;PTH停药8周后大鼠股骨与腰椎骨密度、股骨三点弯曲与腰椎压缩最大载荷及腰椎骨小梁百分面积均较停药前显著降低（P＜0.05～0.001）,但仍显著高于OVX对照组（P＜0.05～0.001）.结论外源性PTH（1-34）可显著增加OVX大鼠的骨量,提高骨力学性能,改善骨微结构,对卵巢摘除诱导的大鼠骨质疏松具有明显治疗作用;停药后出现骨量的快速丢失,骨力学性能下降等变化,但仍显示出其对OVX大鼠骨骼的保护作用.     

维生素K2及其与性激素联合应用对去卵巢大鼠骨的影响

目的观察维生素K2（vitamin K2,VK2）及其与性激素（sex hormone,SH）联合应用对去卵巢大鼠骨质疏松模型预防的效果。方法30只SPF级10月龄雌性SD大鼠按体重随机分为4组,行卵巢切除（OVX,n=22）或假手术（Sham,n=8）,术后2周给以不同的药物干预：VK2组（OVX＋VK2,n=7）、VK2＋SH组（OVX＋VK2＋SH,n=7）;OVX组（n=8）和假手术组不做药物干预。14周后检测血骨特异性碱性磷酸酶（BALP）和尿脱氧吡啶啉（uDPYD）;测定骨密度（BMD）。牺牲后进行股骨三点弯曲实验和股骨远端骨组织形态计量学测定。结果①骨转换指标：OVX组较Sham组BALP和uDPYD显著升高,骨转换加快。与OVX组相比,VK2组uDPYD明显增加,而BALP没有统计学差异;VK2＋SH组BALP和uDPYD均下降。②BMD：标化体重,OVX组腰椎和股骨BMD明显低于Sham组,VK2组腰椎BMD显著高于OVX组,VK2＋SH组BMD没有变化。③股骨远端形态计量学：OVX组与Sham组相比,骨小梁厚度变薄,分离度增加,数量减少,但无统计学意义,骨形成和骨吸收参数均升高,其中骨形成率（BFR/Bs）、类骨质周长百分数（%O.Pm）与Sham组有统计学差异。与OVX组相比,用药组对骨量和骨小梁结构无改善,均有降低骨形成参数的趋势,从数值上看,VK2＋SH组降低的程度〉VK2组。VK2＋SH组骨矿化延迟时间（MLT）、BFR/Bs下降最为显著。④股骨三点弯曲实验结果：VK2＋SH组最大载荷较其他各组显著降低,最大应变和弹性模量各组之间无统计学差异。结论单用VK2可以增加去卵巢大鼠腰椎BMD,但作用机制尚不清楚。VK2与SH合用未发现对骨健康有利。     

降钙素对卵巢切除大鼠股骨骨折愈合的影响

目的观察降钙素对卵巢切除大鼠股骨骨折愈合的作用，为临床上治疗骨质疏松性骨折提供实验依据。方法50只雌性、14周龄SD大鼠共分成5组，每组10只。分成假手术组（Sham，G1），双侧卵巢切除术组（OVX，G2），假手术＋骨折组（Sham＋F，G3），卵巢切除术＋骨折组（OVX＋F，G4），卵巢切除＋骨折＋降钙素药物组（OVX＋F＋CT，G5），骨折组大鼠均采用右股骨中段横行骨折，髓内针固定；降钙素采用皮下给药，隔日1次（16IU·kg^-1）。所有大鼠于术后4周杀死，取右侧股骨标本。然后，分别进行CR摄片、组织形态学观察，并应用双能X线骨密度仪（DEXA）测量右股骨整体、远段和中段骨密度以及BMP-2免疫组化观察，并应用病理图像分析仪对BMP-2免疫组化进行光密度测量。结果（1）OVX组与Sham组比较，BMD显著下降。（2）OVX＋F＋CT组与OVX＋F组比较：骨痂mBMD显著增高；BMP-2的表达无显著性差异。结论降钙素对OVX大鼠股骨骨折具有明显促进骨折愈合的作用，加速编织骨向板层骨的演变过程。     

葛根异黄酮联合VitD3对去卵巢骨质疏松大鼠骨组织构造的影响

目的观察葛根异黄酮(TIP)联合VitD_3对去卵巢骨质疏松大鼠骨组织构造的影响,探讨其联合作用是否产生协同效应。方法将3月龄健康雌性SD大鼠随机分为OVX组和Sham组,运用去除大鼠双侧卵巢的方法构建绝经后骨质疏松动物模型,手术后3个月进行重新分组,分别为:Sham组、OVX组、OVX+TIP组、OVX+TIP+VitD_3组,每组6只,连续给药2个月。给药结束后采集动物血清以及胫骨、股骨组织标本,检测血清E_2,同时运用病理图像分析系统对骨组织构造进行观察和检测。结果 OVX大鼠血清E_2较Sham组显著降低,给药TIP后大鼠血清E_2回升,但OVX+TIP组、OVX+TIP+VitD_3组血清E_2差异不显著(P0.05)。OVX大鼠胫骨、股骨骨小梁体积百分率、骨小梁厚度较Sham组显著降低(P0.01),骨小梁间距较Sham组显著增大(P0.01)。OVX+TIP组胫骨、股骨骨小梁体积百分率、骨小梁厚度较OVX组显著升高(P0.05),骨小梁间距较OVX组显著减小(P0.05),但是OVX+TIP组胫骨、股骨形态计量学静态指标与Sham组差异显著(P0.05),OVX+TIP+Vit D3组胫骨、股骨形态计量学静态指标与Sham组无显著差异(P0.05)。结论葛根异黄酮与Vit D3联合给药对去卵巢骨质疏松大鼠骨组织的修复作用优于葛根异黄酮单独给药。     

血清中骨质疏松相关蛋白分子标志物的筛选研究

目的：通过蛋白芯片筛选血清中反映早期绝经后骨质疏松症发生、发展的标志性分子。方法3月龄雌性SD大鼠20只，随机分为卵巢切除（ovariectomized, OVX）组和假手术（sham operation, Sham）组，每组10只，分别进行卵巢去势手术和假手术处理。术后2、4、6、8周对两组大鼠进行活体显微CT扫描，测量股骨远端骨密度及相关松质骨形态计量学动态参数；同时经内眦静脉取血，利用蛋白芯片检测血清中不同蛋白因子的含量。结果显微CT检测结果显示OVX组大鼠骨密度（BMD）、相对骨体积（BV/TV）、骨小梁厚度（Tb.Th）、骨小梁数目（Tb.N）从第4周开始下降，骨小梁分离度（Tb.Sp）开始上升， Sham组未见明显变化；到第8周各指标在OVX组与Sham组之间差异有统计学意义（P＜0.05）。蛋白芯片检测结果显示OVX组中干扰素?γ（IFN?γ）、β神经生长因子（b?NGF）分别从术后4周和6周后开始升高，同Sham组比较均至第8周具有明显差异（P＜0.05）。结论 IFN?γ和b?NGF水平在绝经后骨质疏松早期开始增高，可考虑作为诊断早期绝经后骨质疏松症发生的新型蛋白分子。     

rhPTH_((1-34))治疗OVX大鼠骨质疏松延后效应的初步研究

目的观察重组人甲状旁腺激素(134)[rhPTH(134)]对卵巢摘除(OVX)大鼠骨质疏松症的治疗作用及停药后效应。方法应用双侧卵巢摘除方法建立模拟绝经后骨质疏松大鼠模型;给予皮下注射20μgkgdrhPTH(134)治疗8周,观察其骨量、骨生物力学、骨小梁形态计量及骨代谢相关血、尿生化指标,综合评价PTH对模型大鼠的治疗效果;同时观察停药8周后上述指标的变化。结果外源性PTH(134)治疗能显著增加模型大鼠的骨量、骨力学性能,改善骨微结构、增加骨转换。用药组的骨密度、股骨三点弯曲与腰椎压缩最大载荷、腰椎骨小梁百分面积显著高于对照组(P<0.05～0.001);血ALP(P<0.05～0.01)与尿Pyd(P<0.05)保持高水平;PTH停药8周后大鼠股骨与腰椎骨密度、股骨三点弯曲与腰椎压缩最大载荷及腰椎骨小梁百分面积均较停药前显著降低(P<0.05～0.001),但仍显著高于OVX对照组(P<0.05～0.001)。结论外源性PTH(134)可显著增加OVX大鼠的骨量,提高骨力学性能,改善骨微结构,对卵巢摘除诱导的大鼠骨质疏松具有明显治疗作用;停药后出现骨量的快速丢失,骨力学性能下降等变化,但仍显示出其对OVX大鼠骨骼的保护作用。     

高脂饮食通过抑制Wnt/β-catenin信号介导对骨质疏松大鼠骨密度和骨修复的负面影响

目的 评估高脂饮食（HFD）对骨质疏松大鼠骨密度（bone mineral density, BMD)及骨修复的影响并探讨可能的机制。方法 将雌性SD大鼠随机分为三组：假手术卵巢切除组（Sham）、手术卵巢切除模型组（OVX）、手术卵巢切除模型+HFD（OVX+HFD）;随后所有大鼠在双侧去卵巢手术或假手术后12周基础上制作双侧股骨干建立骨缺损模型,OVX+HFD组大鼠在股骨上接受HFD干预4周。随后使用影像学、血清学、骨生物力学以及基因水平检测来评估骨修复效果。结果 与Sham组相比,OVX和OVX+HFD组的血清E2、ALP水平均显著降低( P<0.05),而TRAP水平均显著升高(P<0.05);OVX和OVX+HFD组之间有显著差异(P<0.05)。Micro-CT检测显示OVX+HFD组骨修复效果较OVX和Sham组明显降低;定量检测结果显示OVX+HFD组的BMD、Tb.N和Tb.Th显著小于OVX组(P<0.01),而Tb.Sp(P<0.05)在OVX+HFD组中明显大于在OVX组。生物力学显示HFD干预后明显降低了去卵巢大鼠骨缺损部位的机械强度,包括大鼠股骨的极限载荷、刚度、能量吸收和弹性模量(P均<0.05);基因检测表明与OVX组相比,OVX + HFD组Smad2、Smad3和GSK-3βmRNA表达显著增加(P<0.01),而Wnt1和β-cateninmRNA表达均显著降低(P<0.01)。结论 HFD对骨质疏松状态下骨缺损愈合有负面影响,而这种影响可能是通过对Wnt/β-catenin信号传导抑制来实现的。     

曲古抑菌素A促进去卵巢大鼠钛植入物骨整合

目的 探讨TSA对去卵巢大鼠TI骨整合的影响。方法 将30只健康3月龄雌性SD大鼠随机分为Sham组（n=5）和OVX组（n=25）。正常饲养3个月后,两组各选取5只大鼠处死,取股骨远端样本行Micro-CT和HE染色以鉴定是否成功建立骨质疏松模型。随后在OVX组剩余大鼠双侧股骨干骺端植入直径1.5 mm TI,并将其分为2组：Control组（n=10）和TSA组（n=10）。连续给药4周。给药结束后处死全部大鼠并取股骨样本行Micro-CT扫描、HE染色以及Masson染色,ELISA法检测,拔钉实验。结果 与Sham组对比,Micro-CT显示OVX组BMD、BV/TV、Tb.Th、Tb.N降低（P<0.05）,而Tb.Sp、SMI升高（P<0.05）,HE染色显示OVX组骨小梁数量明显降低。与Control组对比,Micro-CT显示TSA组BMD、BV/TV、Tb.Th、Tb.N 、Conn.D均升高（P<0.05）,而Tb.Sp、SMI降低（P<0.05）,HE染色、Masson染色显示TSA组骨小梁数量、新生骨数量均升高,ELISA法检测结果显示TSA组OCN、BMP2均升高,拔钉实验显示TSA组TI轴向拔出力增大。结论 TSA通过上调OCN、BMP2等成骨相关蛋白,促进骨小梁形成和新骨形成,进而改善去卵巢大鼠TI骨整合。     

中药骨康对去卵巢大鼠腰椎骨形态计量学的影响

目的 探讨中药骨康对卵巢切除大鼠骨质疏松症的治疗作用。方法 选择6m龄SD大鼠48只。随机分为假手术模型组（Sham）、手术模型组（OVX）、尼尔雌醇组（E2）、中药骨康组。切除大鼠卵巢3m后。大鼠骨质疏松症模型制备成功，分别给予尼尔雌醇、中药骨康灌胃治疗，并与Sham组和OVX组对照。治疗3m后，体内双荧光标记，取第2腰椎包埋切片。全自动图像分析及松质骨骨形态计量学软件处理。观察中药对骨形态计量学参数的影响。结果 卵巢切除后大鼠骨小梁面积百分数（％Tb．Ar）下降35．84％，骨小梁数量（Tb．N）下降16．60％，骨小梁宽度（Tb．Th）下降25．79％，表明绝经后骨质疏松症动物模型成立。骨康治疗3个月后，与OVX组相比，Oc．N／mm^2下降42．80％，有显著性差异（P〈0．01）；％Tb．Ar、Tb．Th、Tb．N和MAR有上升趋势（P〉0．05）；15．Sp，％L．Pm、BFR／BS、BFR／TV和Oc．N／mm，BFR／BV有下降趋势（P〉0．05）。结论 中药骨康具有降低骨转换以及促进骨形成和抑制骨吸收的双重作用，说明中药骨康对骨质疏松有明显的治疗作用。     

狄诺塞麦对去卵巢大鼠股骨干骺端骨缺损修复影响的实验研究

目的研究狄诺塞麦(DMAb)对去卵巢大鼠股骨干骺端骨缺损修复的影响。方法 40只健康雌性SD大鼠随机行假手术(Sham,n=15)和切除双侧卵巢(OVX,n=25)手术,术后12 w每组各取5只大鼠处死取股骨行双能X线骨密度仪检测来确定骨质疏松的建立情况,随后各组大鼠在双侧股骨干骺端建立3 mm圆形缺损,术后随机分成3组:Sham、OVX组及DMAb组。术后第一天DMAb组给予DMAb皮下注射一次,剂量为60 mg,正常饲养12 w后所有大鼠处死取股骨行Micro-CT、骨生物力学、组织切片检测。结果和OVX组、Sham组股骨干骺端缺损愈合相比,DMAb组大鼠股骨干骺端缺损区域有较高的最大载荷、骨密度(BMD)、骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小粱数量(Tb.N)、连接密度(Conn.D)、骨矿化沉积率(MAR)和较低的骨小粱分离度(Tb.Sp),且各组之间比较差异有统计学意义(P0.05)。结论 DMAb通过增加骨量,促进骨组织矿化及提高骨骼强度来加速去势大鼠股骨干骺端骨缺损的修复。     

阿胶强骨口服液对去卵巢骨质疏松大鼠骨密度、生物力学、25-(OH)D3和1,25-(OH)2D3的影响

目的：研究阿胶强骨口服液对去卵巢骨质疏松大鼠骨密度（BMD）、生物力学、25-（OH）D3和1，25-（OH）2D3，的影响，探讨阿胶强骨口服液治疗原发性骨质疏松症的疗效机制。方法：4月龄健康雌性SD大鼠36只，随机分为3组，每组12只，分别为模型组，假手术组，阿胶强骨口服液治疗组。除假手术组外所有大鼠手术摘除双侧卵巢后导致雌激素缺失从而诱导骨质疏松症模型，分别在实验的第4、8、12周采用DEXA法分析股骨头及粗隆部的骨密度，生物力学技术分析股骨头生物力学参数，酶联免疫吸附方法检测25-（OH）D3和1,25-（OH）2D3的含量。结果：阿胶强骨口服液治疗组与模型组比较，股骨头及粗隆部骨密度明显提高（P〈0．05）；最大载荷（ML）及最大压应变（MS）等指标明显增强（P〈0．05）；血液、肝脏和肾脏组织中25-（OH）D3和1，25-（OH）2D3的含量明显提高，且组间比较差异有统计学意义（P〈0．05）。阿胶强骨口服液治疗组与假手术组比较差异无统计学意义（P〉0．05）。结论：阿胶强骨口服液在雌激素缺失早期即可在蛋白水平上调节25-（OH）D3和1，25-（OH）2D3的表达，激活骨代谢，提高骨密度，增强骨质量，起到预防骨质疏松的作用。     

Role of parathyroid hormone and 1,25-dihydroxyvitamin D3 in the development of osteopenia in oophorectomized rats

Summary The effect of ovarian insufficiency on calcium metabolism has been thought to involve an increased bone resorptive effect of parathyroid hormone and possible impaired synthesis of 1,25-dihydroxyvitamin D₃. In the present study a rat model allowing for controlled serum levels of parathyroid hormone and 1,25-dihydroxyvitamin D₃ was used. Oophorectomy in this species is associated with increased serum levels of 1,25-dihydroxyvitamin D₃ and decreased bone mass. Although thyroparathyroidectomy increased bone mass, an increased sensitivity of bone to parathyroid hormone in oophorectomized rats was not observed. Thus the development of the osteopenia did not seem to be related to increased parathyroid hormone sensitivity or to reduced levels of 1,25-dihydroxyvitamin D₃. Exogenous 1,25-dihydroxyvitamin D₃ increased bone mass in oophorectomized as well as intact rats. Intestinal calcium transport was increased by moderate doses of 1,25-dihydroxyvitamin D₃. Intestinal calcium transport was also reduced by thyroparathyroidectomy and increased by the administration of parathyroid extract. A tendency for increased accumulation of 1,25-dihydroxyvitamin D₃ in blood in oophorectomized rats has been noted. It is suggested that the tendency to hypercalcemia in ovarian-insufficient females given 1-hydroxylated vitamin D compounds may be related to a diminished metabolism of 1,25-dihydroxyvitamin D₃.     

Remarkable increase in lumbar spine bone mineral density and amelioration in biochemical markers of bone turnover after parathyroidectomy in elderly patients with primary hyperparathyroidism: a 5-year follow-up study

We evaluated the efficacy of parathyroidectomy (PTX) on bone mineral density (BMD) and hormonal and biochemical markers of bone metabolism in elderly primary hyperparathyroidism (PHPT) patients, and followed these patients for 5 years after PTX. Eleven PHPT patients were enrolled and were followed for 5 years by measuring lumbar spine BMD (LSBMD), femoral BMD (FBMD), radial BMD (RBMD), parathyroid hormone (PTH), 1,25-dihydroxyvitamin D [1,25(OH)₂D], serum calcium (SCa), inorganic phosphate (iP), bone-specific alkaline phosphatase (BAP), intact osteocalcin (IOC), urinary excretion of type I collagen cross-linked N-telopeptide (NTx), and urinary deoxypyridinoline (DPD). PTX produced significant increases in LSBMD of 12%, 19%, and 29% as compared with pretreatment levels after 1, 3, and 5 years, respectively (P < 0.01, compared to baseline), whereas there was no significant increase in FBMD and a slight decrease in RBMD. SCa and iP levels remained normal over the five years. PTX also resulted in significant decreases in PTH, 1,25(OH)₂D, BAP, IOC, NTx, and DPD that continued for at least 3 years after PTX. In conclusion, PTX seemed effective to normalize various markers of bone metabolism in elderly PHPT patients and is recommended to patients with low LSBMD to prevent future fractures. On the other hand, the use of PTX for low FBMD or RBMD patients requires further discussion.     

Evaluation of bone strength using finite-element analysis in patients with ossification of the posterior longitudinal ligament

BACKGROUND CONTEXTPatients with ossification of the posterior longitudinal ligament (OPLL) are often reported to have increased bone mineral density (BMD). The bone strength of the proximal femur measured by quantitative computed tomography-based finite element analysis (QCT/FEA) is reportedly comparable between healthy subjects with and without OPLL. However, the bone strength in symptomatic OPLL patients remains unknown.PURPOSETo investigate bone strength measured by QCT/FEA in symptomatic patients with OPLL.STUDY DESIGN/SETTINGA single-center prospective observational study.PATIENT SAMPLEA total of 157 patients with cervical or thoracic compressive myelopathy were included in the study.OUTCOME MEASURESWe analyzed patients’ characteristics, Japanese Orthopedic Association (JOA) score, serum laboratory tests including calcium (Ca), inorganic phosphate (Pi), and bone turnover markers, BMD of the proximal femur and lumbar spine measured using dual-energy X-ray absorptiometry, and predicted bone strength (PBS) of the proximal femur and lumbar spine measured using QCT/FEA.METHODSEligible patients were divided into the non-OPLL and OPLL groups. We compared the patients’ characteristics, JOA scores, laboratory data, BMD, and PBS of the proximal femur and lumbar spine between the non-OPLL and OPLL groups among total, male, and female patients by performing Fisher's exact test for categorical variables and the unpaired t test for continuous variables. Then, we used the inverse probability weighted logistic regression model after calculating propensity scores to compare the bone metabolism-associated markers, BMD, and PBS measurements between the groups.RESULTSAmong the eligible 157 patients, 68 were in the non-OPLL group and 89 were in the OPLL group. Compared with the non-OPLL group, the OPLL group had a significantly younger age and higher BMI in the total, male, and female patients. The JOA scores in the total and female patients were significantly higher in the OPLL group than in the non-OPLL group. The OPLL group showed significantly lower Ca levels in the female patients and significantly lower Pi levels in the total or male patients compared with the non-OPLL group in the inverse probability weighting method. The BMD of the proximal femur and lumbar spine and the PBS of the proximal femur were significantly higher in the OPLL group than in the non-OPLL group. There were no significant differences in the PBS and BMD between the male subgroups. However, the BMD and PBS of the proximal femur and lumbar spine were significantly higher in the OPLL females than in the non-OPLL females.CONCLUSIONSHyperostosis of the posterior longitudinal ligament in OPLL was associated with higher bone strength by QCT/FEA, especially in female OPLL patients.     

Serum ferritin levels are positively associated with bone mineral density in elderly Korean men: the 2008–2010 Korea National Health and Nutrition Examination Surveys

A possible negative effect of iron overload on bone metabolism has been suggested by the fact that patients with hemochromatosis, thalassemia, and sickle cell anemia have lower bone mineral density than the general population. However, the influence of iron overload on bone health in the general population is uncertain. The aim of this study was to investigate the relationship between serum ferritin levels and bone mineral density (BMD) in elderly Koreans. A total of 2,943 subjects aged 65 years and over who participated in the 2008–2010 Korea National Health and Nutrition Examination Surveys were included in this study. Age, physical activity, current smoking status, alcohol consumption, education level, household income, and dietary assessment were surveyed by a face-to-face interview. BMD was measured at the lumbar spine and femur by dual-energy X-ray absorptiometry, and other biochemical markers, including serum ferritin, 25-hydroxyvitamin D₃, serum alkaline phosphatase, and parathyroid hormone, were assayed. After adjusting for age and body mass index, we found an association between BMD of the total lumbar spine, total femur, and femur neck and levels of alkaline phosphatase, parathyroid hormone, vitamin D₃, and daily intake of calcium and protein. Serum ferritin levels were positively associated with BMD of the total lumbar spine, total femur, and femur neck after adjusting for all covariates in men, but not in women. This study suggests a positive association between serum ferritin levels and BMD in elderly South Korean men without hematologic disorders. Further study is warranted to verify the effects of iron on bone metabolism.     

Modifications of Bone and Connective Tissue after Orthostatic Bedrest

Eight male volunteers were submitted to a 6-week anti-orthostatic bedrest trial followed by a 1-month reambulation period. We prospectively monitored whole-body composition by dual-energy X-ray absorptiometry, bone and connective tissue metabolism by biochemical markers and calcium regulating hormones by 1–84 parathyroid hormone and 1,25-dihydroxyvitamin D₃. Bone mineral density (BMD) did not vary significantly; however, a trend toward an increase in head BMD and a decrease in trunk, lumbar vertebrae and lower limb BMD was observed. A decrease in the lower limb lean content occurred by day 27 and was maximum by day 42 after the beginning of bedrest; it normalized by day 30 after bedrest. The serum levels of both osteocalcin and C-terminal crosslinked telopeptide of type I collagen increased as a consequence of bedrest. A slight increase in the serum levels of the N-terminal propeptide of type III collagen, a marker of connective tissue metabolism, was observed during the bedrest period. Except for the C-terminal extension propeptide of type I collagen, all markers decreased to baseline pre-immobilization levels during the 1-month recovery phase. Serum PTH and 1,25-dihydroxyvitamin D₃ levels were low during the bedrest period and rose during the reambulation phase. These results seem to reflect early changes in bone and connective tissue metabolism as a result of bedrest unloading, but their order of magnitude remains moderate, thus emphasizing the necessity to perform longer-duration trials. Received: 10 December 1998 / Accepted: 14 June 1999     

The effects of stable strontium on calcium metabolism.: II. Effects of 1α-hydroxyvitamin D3 in strontium-fed rats,and inhibitory effect of strontium on bone resorptionin vitro

It has been postulated that the effect of strontium on bone metabolism due to the reduced plasma 1,25-dihydroxyvitamin D₃ level following the inhibition of 1α-hydroxylation by strontium. The effects of strontium were examined on intestinal calcium absorption when rats were received synthetic 1α-hydroxyvitamin D₃. Four groups of rats at the age of 36 days were fed a semi-synthetic vitamin D-deficient diet for 4 weeks containing 1% strontium and vitamin D₃ (Sr-D group), 1% strontium and 1α-hydroxyvitamin D₃ (Sr-α group), vitamin D₃ (Co-D group), or 1α-hydroxyvitamin D₃ (Co- α group), respectively. At the age of 60 days, calcium and strontium balance studies were conducted to determine intestinal calcium absorption over a 3-day period, and 1,25-dihydroxyvitamin D level was then measured. Serum 1,25-dihydroxyvitamin D in Sr-D group was undetectable, and intestinal calcium absorption significantly decreased. Replacement of vitamin D₃ with 1α-hydroxyvitamin D₃ recovered serum 1,25-dihydroxyvitamin D to the level in Co-D group. However, this substitution in Sr-α group failed to increase intestinal calcium absorption. We also examined the direct of strontium on bone resorption using⁴⁵Ca pre-labeled mouse calvaria. Strontium was injected every day until sacrifice, and percent⁴⁵Ca release from cultured calvariae was measured. Bone resorption was inhibited by strontium dose-dependently in groups which had and had not received parathyroid hormone in culture. These results suggest that strontium inhibits intestinal calcium absorption and has a direct inhibitory effect on bone resorption.     

Changes of basic bone turnover parameters in short-term and long-term patients with spinal cord injury

The bone mineral density (BMD), the cross- links (PYD, DPD and NTx) and the bone specific alcaline phosphatase (BAP) was investigated in a cross-sectional study in 62 male patients with spinal cord injury (SCI), n = 28 short-term (0–1 year after SCI) and n = 34 long-term SCI patients (> 5 years after SCI). Knowledge about this parameters are necessary to find an adequate therapy for this special kind of osteoporosis. Immobilisation osteoporosis in SCI patients is a well-known problem that may lead to pathological fractures. Little is known regarding the extend of the osteoporosis as well as the causative factors. Measurements of the BMD in the proximal femur and the lumbar spine were performed with dual-energy-X-ray-absorptiometry (DEXA), of the osteoblast marker BAP (bone specific alkaline phosphatase) from serum and the osteoclast markers PYD (pyridinoline), DPD (desoxy-pyridinoline) and NTx (N-telopeptide of collagen type I) from urine. We found a significant decrease of BMD in the proximal femur and no relevant change in the lumbar spine compared to an age- and sex correlated control group (Z-score) in short-term and long-term SCI patients. There was a significant bone loss at the proximal femur between short and long-term SCI patients, whereas at the lumbar spine the BMD even slightly increases. Bone resorption (cross-links) was increased in both groups, though in long-term SCI patients it is significantly decreased compared to short-term SCI patients (DPD from 211.7 u/g creatinine to 118.1 u/g creatinine; NTx from 215.1 nmol/mmol creatinine to 83,6 nmol/mmol creatinine). The bone formation marker BAP is slightly below normal range in both groups (12.3 U/l in short-term, 9.7 U/l in long- term SCI patients). Only the proximal femur is affected by the immobilisation osteoporosis of SCI patients, therefore the BMD measurements in these patients should be performed at the lower limb. The problem of the immobilisation osteoporosis in SCI patients is the striking increase of bone resorption and the missing reaction of the bone formation.     

胰岛素抵抗在2型糖尿病时血清维生素 D3和骨密度变化中的意义

目的检测胰岛素抵抗(IR)和2型糖尿病(T2DM)大鼠的胰岛鼠抵抗情况、血清25-(OH)D3和1,25-(OH)2D3水平、腰椎和股骨骨密度(BMD),探讨IR与2型糖尿病时血清维生素D3和骨密度变化中的意义。方法 18月龄wistar大鼠30只,分为正常对照组(N组)、胰岛素抵抗组(I组)、糖尿病组(D组),正常血糖胰岛素钳夹技术(EICT)测定各组大鼠IR,葡萄糖输注速率(GIR)表示IR,放免法测定各组大鼠血25-(OH)D3和1,25-(OH)2D3水平,双能X线骨密度测量仪(DEXA)测定各组大鼠腰椎、股骨BMD。结果 D组和I组GIR相当,均显著低于N组(P0.01),I组1,25-(OH)2D3低于N组(P0.05),高于D组(P0.01),三组间25-(OH)D3无显著差异,I组腰椎、股骨BMD低于N照组,高于D组(P0.05)。结论 IR是2型糖尿病导致血清活性维生素D3降低和骨密度下降的重要病理生理基础。     

A longitudinal study for femoral neck bone mineral density increases in premenopausal caddies using dual-energy X-ray absorptiometry

This longitudinal study examined whether bone mineral density (BMD) of the lumbar spine and proximal femur is maintained in premenopausal caddies (n = 6; mean age 37.8 years) in comparison with desk workers (n = 6; mean age 40.8 years) at the same golf club. BMD was followed for 12 months using dual-energy X-ray absorptiometry (DXA) and bone metabolic markers and athletic ability were also examined. Longitudinally, for caddies, the change per year in BMD of the lumbar spine was +0.009 g/cm², while that of the proximal femur was +0.022 g/cm², showing significant differences (P < 0.05 by signed-rank test). Their athletic ability, in terms of leg-press power, also significantly increased, whereas bone metabolic markers, such as serum alkaline phosphatase, 1,25-(OH)₂ vitamin D₃, parathyroid hormone and the deoxypyridiniline/creatinine ratio, did not show significant changes. For desk workers, the change per year in BMD of the lumbar spine was +0.011 g/cm², while that of the proximal femur was −0.006 g/cm². Their BMD, athletic ability and bone metabolic markers did not show significant changes. These findings support the results of our previous study, that premenopausal women can achieve continuous gain in femoral neck BMD by regular intense athletic activity, and suggest that this is also true by the continuous extensive walking of golf caddies. Received: May 17, 2000 / Accepted: August 22, 2000