Individual and combined effects of exercise and alendronate on bone mass and strength in ovariectomized rats

Exercise and bisphosphonate therapies increase bone strength by primarily increasing bone formation and reducing resorption, respectively. Based on these different mechanisms of action, it is possible that combined introduction of exercise and bisphosphonate therapies generates greater improvements in bone mass and strength than either intervention alone. The aim of this study was to examine the individual and combined effects of exercise (treadmill running) and bisphosphonate therapy (alendronate [ALN]) on bone mass and strength in ovariectomized (OVX) rats. Seven-month-old virgin female rats were randomly assigned to either a sham-OVX group (n=13) or one of four OVX groups: vehicle-treated cage-control (VEH-CON, n=10); ALN-treated cage-control (ALN-CON, n=13); vehicle-treated plus treadmill running (VEH-RUN, n=13); and ALN-treated plus treadmill running (ALN-RUN, n=13). ALN-treated groups received twice-weekly ALN (0.015 mg/kg), and exercise groups ran on a motorized treadmill at a 5% incline for 60 min/day, 22-24 m/min, 5 days/week. In vivo measurements included dual-energy X-ray absorptiometry (DXA) of whole-body bone mineral content (BMC), and ex vivo measurements included DXA, micro-computed tomography (muCT), and mechanical testing of the femur and L4 vertebrae. After 14 weeks of intervention, exercise and ALN had additive benefits on whole body and proximal femur BMC, cross-sectional area of the L4 vertebrae, and mechanical properties of the mid-shaft femur. In comparison, for total and mid-shaft femur BMC, L4 vertebrae BMC, and mid-shaft femur cortical thickness and area, there were significant exercise and ALN interactions indicating that the two interventions worked in synergy to enhance bone properties. Supporting the contention that ALN and exercise function via distinct mechanisms of action, ALN successfully reduced medullary canal area suggesting it reduced endocortical bone resorption, whereas exercise augmented periosteal perimeter suggesting it stimulated periosteal bone formation. In summary, we found combined treadmill running and ALN to be more beneficial in preventing declines in bone mass and strength following OVX than the introduction of either intervention alone. These data suggest that a comprehensive program of bisphosphonate therapy and weight-bearing exercise may be an effective method for preventing and treating osteoporosis in post-menopausal women.     

Combined effects of exercise and propranolol on bone tissue in ovariectomized rats.

The bone response to physical exercise may be under control of the SNS. Using a running session in rats, we confirmed that exercise improved trabecular and cortical properties. SNS blockade by propranolol did not affect this response on cortical bone but surprisingly inhibited the trabecular response. This suggests that the SNS is involved in the trabecular response to exercise but not in the cortical response. INTRODUCTION: Animal studies have suggested that bone remodeling is under beta-adrenergic control through the sympathetic nervous system (SNS). However, the SNS contribution to bone response under mechanical loading remains unclear. The purpose of this study was to examine the preventive effect of exercise coupled with propranolol on cancellous and cortical bone compartments in ovariectomized rats. MATERIALS AND METHODS: Six-month-old female Wistar rats were ovariectomized (OVX, n = 44) or sham-operated (n = 24). OVX rats received subcutaneous injections of propranolol 0.1 mg/kg/day or vehicle and were submitted or not submitted to treadmill exercise (13 m/minute, 60 minutes/day, 5 days/week) for 10 weeks. Tibial and femoral BMD was analyzed longitudinally by DXA. At death, the left tibial metaphysis and L(4) vertebrae were removed, and microCT was performed to study trabecular and cortical bone structure. Histomorphometric analysis was performed on the right proximal tibia. RESULTS: After 10 weeks, BMD and trabecular strength decreased in OVX rats, whereas bone turnover rate and cortical porosity increased compared with the Sham group (p < 0.001). Either propranolol or exercise allowed preservation of bone architecture by increasing trabecular number (+50.35% versus OVX; p < 0.001) and thickness (+16.8% versus OVX; p < 0.001). An additive effect of propranolol and exercise was observed on cortical porosity but not on trabecular microarchitecture or cortical width. Biomechanical properties indicated a higher ultimate force in the OVX-propranolol-exercise group compared with the OVX group (+9.9%; p < 0.05), whereas propranolol and exercise alone did not have any significant effect on bone strength. CONCLUSIONS: Our data confirm a contribution of the SNS to the determinants of bone mass and quality and show a antagonistic effect of exercise and a beta-antagonist on trabecular bone structure.     

刺五加苷E对去卵巢小鼠骨量及神经肽的影响

目的 研究刺五加苷E(Eleutheroside E,EE)对去卵巢(OVX)小鼠骨量以及神经肽的影响。方法 选取24只7周龄C57BL6/J雌性小鼠,平均分为假手术组(Sham组)、OVX组、EE低剂量组(EE-L组)和EE高剂量组(EE-H组),EE-L组和EE-H组在OVX基础上分别予EE 20 mg/(kg·d)和40 mg/(kg·d)灌胃,Sham组和OVX组以等体积1%羟甲基纤维素钠(CMC-Na)灌胃。12周后收集小鼠左侧股骨和血清标本。左侧股骨行Micro-CT扫描;ELISA法检测血清中骨吸收指标抗酒石酸酸性磷酸酶(TRAP)、骨形成指标Ⅰ型原胶原氨基端肽(P1NP)、炎性细胞因子肿瘤坏死因子-α(TNF-α)、白细胞介素6(IL-6)、白细胞介素10(IL-10)以及神经肽降钙素基因相关肽(CGRP)、神经肽P物质(SP)、血管活性肠肽(VIP)、神经肽Y (NPY)的含量。结果 与Sham组相比,OVX组小鼠骨密度(bone mineral density, BMD)、骨体积分数(BV/TV)、骨小梁数量(Tb.N)、P1NP、IL-10、CGRP、SP、VIP...     

Comparative effects of 17β-estradiol,raloxifene and genistein on bone 3D microarchitecture and volumetric bone mineral density in the ovariectomized mice

Summary This study assessed the effect of estradiol, raloxifene and genistein on the preservation of bone 3D-microarchitecture and volumetric bone mineral density (vBMD) in the ovariectomized mouse model. Our results indicated that raloxifene was more effective in preserving bone ovariectomized-induced changes, the advantage being concentrated in both bone microarchitecture and vBMD. Introduction This study assessed the effect of different estrogen receptor (ER) agonists on the preservation of bone 3D-microarchitecture and volumetric bone mineral density (vBMD) in the ovariectomized (OVX) mouse model. Methods Twelve-week-old female C57BL/6 mice were randomly assigned to one of five groups: (1) SHAM-operated + vehicle; (2) OVX + vehicle; (3) OVX + 17β-estradiol (5 μg/kg); (4) OVX + raloxifene (1 mg/kg); (5) OVX + genistein (25 mg/kg), during 4-weeks. Bone microarchitecture and trabecular, cortical and total vBMD of distal femur were imaged by ex vivo microcomputed tomography (micro-CT). Results Ovariectomy produced a global deterioration involving both trabecular and cortical 3D-microarchitecture and vBMD. Raloxifene maintained both microarchitecture and vBMD, whereas estradiol prevented deterioration of some microstructural parameters, such as trabecular thickness (Tb.Th), trabecular bone pattern factor (Tb.Pf), and cortical periosteal perimeter (Ct.Pe.Pm), but did not completely block the loss in vBMD. Mice treated with genistein exhibited the less favourable profile in both vBMD and microstructural parameters preserving only cross-sectional bone area (B.Ar) and Ct.Pe.Pm in cortical bone. Conclusion Our data indicate that, at the selected doses, raloxifene was more effective in preserving bone OVX-induced changes than either estradiol or genistein, the advantage being concentrated in both bone microarchitecture and vBMD.     

染料木黄酮对去势大鼠骨组织形态计量学参数的影响

目的　研究染料木黄酮对去势大鼠股骨远端形态计量学参数的影响 ,为染料木黄酮防治骨质疏松提供理论依据。方法　雌性Wistar大鼠 4 7只 ,按体重随机分为 6组 :假手术组、去势对照组、去势 雌激素组 (2 0 μg/kg体重 )、去势 染料木黄酮组 (染料木黄桐剂量分别为 2 5、5 0、10 0mg/kg体重 )。饲养 3个月后处死 ,测定股骨形态计量学参数。结果　去势组与假手术组比较 ,骨小梁体积、平均骨小梁板密度和厚度减少 ,平均骨小梁板间隙和类骨质宽度增加 ,矿化延迟时间和类骨质成熟时间延长 ,且差异均具有显著性 (P <0. 0 5 )。染料木黄酮各组与去势组比较 ,骨小梁体积和平均骨小梁板厚度增加 ,平均骨小梁板间隙变窄 ,矿化延迟时间和类骨质成熟时间缩短 ,且差异均有显著性 (P <0 . 0 5 )。结论　染料木黄酮有促进骨形成 ,减少切除卵巢后骨量丢失的作用。     

The influence of long-term treadmill exercise on bone mass and articular cartilage in ovariectomized rats

Background  

Loss of bone quality and deterioration of articular cartilage are commonly seen after menopause. While exercise may protect against tissue degeneration, a clear link has yet to be established. The aim of the present study is to investigate the influence of long-term treadmill exercise on changes in bone mass and articular cartilage in ovariectomized rats.     

Dietary n-3 fatty acids decrease osteoclastogenesis and loss of bone mass in ovariectomized mice.

The mechanisms of action of dietary fish oil (FO) on osteoporosis are not fully understood. This study showed FO decreased bone loss in ovariectomized mice because of inhibition of osteoclastogenesis. This finding supports a beneficial effect of FO on the attenuation of osteoporosis. INTRODUCTION: Consumption of fish or n-3 fatty acids protects against cardiovascular and autoimmune disorders. Beneficial effects on bone mineral density have also been reported in rats and humans, but the precise mechanisms involved have not been described. METHODS: Sham and ovariectomized (OVX) mice were fed diets containing either 5% corn oil (CO) or 5% fish oil (FO). Bone mineral density was analyzed by DXA. The serum lipid profile was analyzed by gas chromatography. Receptor activator of NF-kappaB ligand (RANKL) expression and cytokine production in activated T-cells were analyzed by flow cytometry and ELISA, respectively. Osteoclasts were generated by culturing bone marrow (BM) cells with 1,25(OH)2D3. NF-kappaB activation in BM macrophages was measured by an electrophoretic mobility shift assay. RESULTS AND CONCLUSION: Plasma lipid C16:1n6, C20:5n3, and C22:6n3 were significantly increased and C20:4n6 and C18:2n6 decreased in FO-fed mice. Significantly increased bone mineral density loss (20% in distal left femur and 22.6% in lumbar vertebrae) was observed in OVX mice fed CO, whereas FO-fed mice showed only 10% and no change, respectively. Bone mineral density loss was correlated with increased RANKL expression in activated CD4+ T-cells from CO-fed OVX mice, but there was no change in FO-fed mice. Selected n-3 fatty acids (docosahexaenoic acid [DHA] and eicosapentaenoic acid [EPA]) added in vitro caused a significant decrease in TRACP activity and TRACP+ multinuclear cell formation from BM cells compared with selected n-6 fatty acids (linoleic acid [LA] and arachidonic acid [AA]). DHA and EPA also inhibited BM macrophage NF-kappaB activation induced by RANKL in vitro. TNF-alpha, interleukin (IL)-2, and interferon (IFN)-gamma concentrations from both sham and OVX FO-fed mice were decreased in the culture medium of splenocytes, and interleukin-6 was decreased in sham-operated FO-fed mice. In conclusion, inhibition of osteoclast generation and activation may be one of the mechanisms by which dietary n-3 fatty acids reduce bone loss in OVX mice.     

The effects of nandrolone decanoate on bone mass and metabolism in ovariectomized rats with osteopenia

The effects of nandrolone decanoate (ND) treatment on bone mass and metabolism were studied in ovariectomized (OVX) rats with osteopenia. The 6-month-old rats were divided into Sham (n = 12) and OVX (n = 24). The OVX rats were allowed to lose bone for 6 weeks. At 6 weeks post ovariectomy, the OVX rats were divided into two groups: (1) OVX + Vehicle and (2) OVX + ND. The effects of ND on bone mineral density (BMD), bone mineral content (BMC), and bone metabolism were studied by dual-energy X-ray absorptiometry (DXA) and biochemical markers including urinary pyridinoline (Pyr), deoxypyridinoline (Dpyr), and serum osteocalcin. After 24 weeks of treatment, histomorphometry of the right tibiae and the wet weight of the gastrocnemius and soleus skeletal muscles were also examined. Ovariectomy resulted in a significant increase in biochemical markers and a significant decrease in spine BMD (0.221 ± 0.016 g/cm² in OVX group vs 0.239 ± 0.008 g/cm² in Sham group) and BMC (0.550 ± 0.055 g in OVX group vs 0.605 ± 0.042 g in Sham group) at 6 weeks post ovariectomy. Spine BMD (0.227 ± 0.017 g/cm²), femoral BMD (0.263 ± 0.012 g/cm²), and bone density of femur (1.035 ± 0.036 g/cm³) in the OVX + ND group were significantly greater than those in the OVX + Vehicle group (0.204 ± 0.013 g/cm² for spine BMD, 0.243 ± 0.009 g/cm² for femoral BMD, 0.938 ± 0.06 g/cm³ for bone density of femur) after 24 weeks of treatment. ND treatment decreased urinary Pyr and Dpyr significantly in OVX rats. Histomorphometric findings indicated that ND-treated rats had greater cancellous bone volume, greater trabecular number, greater trabecular thickness, and less trabecular separation than vehicle-treated OVX rats. OVX rats had greater wet weight of the gastrocnemius and soleus muscles than rats treated with ND. The data suggest that the effect of ND on bone mass is not influenced by the condition of the muscles in OVX rats. Our findings indicate that ND blocks further bone loss by inhibition of bone resorption in OVX rats with osteopenia. Received: August 25, 1999 / Accepted: January 28, 2000     

Comparison of the effects of genistein and zoledronic acid on the bone loss in OPG-deficient mice

Using osteoprotegerin (OPG)-knockout mice, we demonstrated that in vivo the effects of both genistein and 17beta-estradiol (E2) on bone metabolism were completely abolished. In contrast, zoledronic acid could effectively suppress bone resorption and prevent bone loss. INTRODUCTION: The anti-resorptive effects of E2 on bone metabolism are considered to be mediated via modulation of the osteoblast-derived paracrine factor OPG. Recently, the phytoestrogen genistein was found to suppress bone resorption by enhancing osteoblastic production of OPG. However, the mechanism underlying the in vivo effects of E2 and genistein on bone is not entirely understood, and a central question in this regard is whether E2 regulates bone metabolism via an OPG-dependent pathway. METHODS: After mating heterozygous (OPG+/-) mice, homozygous (OPG-/-) and wild-type (WT) with a mixed C57BL/6J x 129/SV background were obtained. The study involved 6-week-old female OPG-/- (n=40) and WT mice (n=8). The OPG-/- mice were randomly divided into 5 groups (n=8 per group) as follows: (1) genistein-treated mice (Gen) that were subcutaneously injected with genistein at a maximal dose (0.8 mg/day); (2) E2-treated mice (E2) that were subcutaneously injected with E2 at a dose (0.03 microg/day); (3) DMSO control mice (DMSO) that were subcutaneously injected with a mixture of dimethylsulfoxide (DMSO) and polyethyleneglycol-300; (4) zoledronic acid-treated mice (Zol) that were subcutaneously injected with zoledronic acid at a dose of (150 microg/kg) twice per week; and (5) H2O control mice that were subcutaneously injected with sterilized water twice per week. The doses of genistein, estrogen and zoledronic acid were selected based on the results of dose-response effect of agents on bone versus uterus in OPG-/- mice. The mice were sacrificed 6 weeks after this intervention. The microarchitecture of the trabecular and cortical bone was assessed by performing microcomputed tomography (micro-CT) for the right proximal tibia. The bone mineral density (BMD) of the left femur was measured by dual-energy X-ray absorptiometry (DXA). The biomechanical parameters of the right femur were determined by a three-point bend testing. Serum levels of bone alkaline phosphatase (B-ALP), tartarate-resistant acid phosphatase-5b (TRACP-5b), and receptor activator of nuclear factor kappaB ligand (RANKL) were determined by performing ELISA. RESULTS: DXA analysis revealed that the total BMD of the femur was not significantly altered in the Gen, E2, H2O, and DMSO groups. The three-point bending test revealed no significant differences in the biomechanical parameters, including ultimate loading, ultimate stress, stiff index, and elastic modulus, and micro-CT analysis revealed that the microarchitectural parameters of the trabecular bone (vBMD, tBMD, BVF, BSF, SMI, Tb.N, Conn.D, Tb.Sp, and Tb.Th) and cortical bone (Ct.Th, Mm, In.Pm, Ot.Pm, Ma.Ar, Ct.Ar, Tt.Ar, Ct.BMD, and Ct.BMC) did not differ among the groups. Genistein and E2 treatment did not alter the serum TRACP-5b, B-ALP, or RANKL levels. However, in addition to increasing the bone mass, zoledronic acid could effectively improve biomechanical parameters and could completely prevent deterioration of the bone architecture in the OPG-/- mice. CONCLUSIONS: The effects of genistein and E2 on bone metabolism in vivo were lost completely in OPG-deficient mice, suggesting that the effect of these agents on bone metabolism seems to be entirely dependent on OPG. In contrast, zoledronic acid could effectively suppress bone resorption and completely prevent the bone loss in the OPG-/- mice--an effect that is likely to be independent of the OPG pathway.     

防己诺林碱对去卵巢小鼠骨代谢及骨微结构的影响

目的探讨防己诺林碱对去卵巢小鼠骨质疏松的保护作用。方法将40只C57BL/6小鼠随机分为空白(假手术)对照组、模型(去卵巢)组、阳性(雌二醇,E2)对照组、防己诺林碱组共4组,每组10只。连续腹腔给药7周后处死小鼠,取股骨及外周血清,通过ELISA法检测骨代谢相关血清学指标:抗酒石酸酸性磷酸酶(TRAc P)、I型胶原羧基末端肽(CTX)及I型胶原氨基末端肽(NTX);通过Micro-CT评估各组小鼠骨组织微结构相关指标:骨小梁百分比(BV/TV)、骨小梁数量(Tb.N)、骨小梁分离度(Tb.Sp)和骨小梁厚度(Tb.Th);通过实时荧光定量PCR检测小鼠骨质疏松骨吸收相关基因的表达情况,包括TRAc P、组织蛋白酶K(Cathepsin K)、活化T细胞核因子1(NFATc1)以及降钙素受体(CTR)。结果与去卵巢模型组比较,防己诺林碱治疗组小鼠BV/TV、Tb.N、Tb.Th显著升高,Tb.Sp明显降低,骨代谢相关指标(TRAc P、CTX、NTX)显著降低,破骨细胞标志基因(TRAc P、Cathepsin K、NFATc1以及CTR)表达水平明显下降。结论防己诺林碱对去卵巢小鼠骨质疏松有保护作用,有望为骨质疏松的临床用药提供新思路。     

葛根对骨质疏松模型小鼠骨密度和骨组织构造的作用

目的 葛根是药食同源的植物,为了全面反映葛根对骨代谢的作用,本研究采用了未经任何提取的葛根,观察了其对去卵巢骨质疏松模型小鼠的骨密度和骨组织构造的作用.方法 麻醉下切除小鼠双侧卵巢,制作雌激素缺乏所致的骨质疏松模型后,令各组小鼠每天分别摄取含有葛根低、中和高剂量的饲料,并设正常组、模型组和雌二醇组.4周后,对小鼠股骨骨密度、骨微细构造以及子宫的作用进行检测.结果 骨密度检测表明,低剂量葛根显著抑制了雌激素缺乏所致股骨骨密度的下降;中剂量葛根完全抑制了这种下降;葛根高剂量组与正常组相比,显著增加了骨密度,其作用强度与雌二醇相当.骨组织形态学分析显示,因雌激素缺乏导致的股骨远端海绵骨的骨量减少、骨小梁宽度的下降以及骨小梁间距的增大,被低剂量葛根显著抑制,被中剂量葛根完全抑制.另外,高剂量葛根显著增加了骨量和骨小梁的宽度.子宫的质量分析显示,小剂量葛根没有明显刺激子宫的作用,中、高剂量葛根轻度抑制了子宫质量的下降,但其强度仅为雌二醇的1/10.葛根抑制骨量减少的作用机制,可能性与抑制破骨细胞的数量有关.结论 葛根不同于雌二醇显著刺激子宫,而具有与雌二醇相当的抗骨质疏松作用,有可能成为预防和治疗女性闭经后骨质疏松症安全而有效的食品或药物.     

有机镓对去势大鼠骨代谢及骨量变化的影响

目的 观察有机镓对去势大鼠骨代谢及骨量变化的影响.方法 将30只大鼠随机分为假手术组、卵巢切除组和有机镓组.除正常对照组外,其他 2 组行卵巢切除.12周后假手术组、卵巢切除组给予PBS治疗,有机镓组给予有机镓干预.8周后取大鼠第五腰椎、股骨分别进行Micro-CT测定骨小梁组织结构;组织形态学测骨小梁占总骨量的百分数(BV/TV);生物力学测定股骨颈机械强度检查;生化指标检测比较血清TRAP、ALP、钙、磷.结果 Micro-CT测试表明有机镓组平均骨小梁厚度(Tb.Th)、皮质厚度Ct.Th)均明显高于卵巢切除组(P＜0.05),BV/TV明显高于卵巢切除组(P＜0.05),破骨细胞数显著减少,有机镓组股骨颈平均最大骨折负荷比卵巢切除组高27.4%,血清TRAP、钙、磷减少(P＜0.05).结论 有机镓减少骨吸收的同时增加骨形成,对于去势大鼠骨量减少有明显的改善作用.     

中等强度跑台运动对去卵巢大鼠后肢骨骨矿物含量和骨密度的双重调节作用

目的 观察中等强度跑台运动对去卵巢大鼠后肢骨骨矿物含量(BMC)和骨密度(BMD)的影响.方法 将60只3月龄未经产雌性SD大鼠按体重随机分为假手术、去卵巢静止、去卵巢运动Ⅰ、去卵巢运动Ⅱ、去卵巢运动Ⅲ和去卵巢运动Ⅳ 6个组.各运动组经1周的跑台适应训练后,按实验设计分别进行为期14周的正式跑台训练.实验结束时,腹主动脉取血处死大鼠,双能χ-射线骨密度仪检测右侧游离股骨和胫骨的BMC和BMD.结果 ①与假手术组相比,去卵巢静止组股骨近端和远端以及胫骨近端BMC和BMD显著下降,但股骨中段以及胫骨中段和远端BMC和BMD无显著变化.②与去卵巢静止组相比,去卵巢运动Ⅰ组股骨近端和远端BMC显著增加,股骨中段以及胫骨3个部位BMC均无显著变化;去卵巢运动Ⅱ组和Ⅲ组股骨和胫骨3个部位BMC 均无显著变化;去卵巢运动Ⅳ组股骨3个部位BMC均无显著变化,而胫骨3个部位BMC均显著下降.③与去卵巢静止组相比,去卵巢运动Ⅰ组股骨近端和远端以及胫骨近端BMD 显著增加, 而股骨中段和胫骨中段和远端BMD无显著变化;去卵巢运动Ⅱ组和Ⅲ组股骨和胫骨任何部位BMD均没有显著变化;去卵巢运动Ⅳ组股骨3个部位BMD无显著变化,而胫骨3个部位BMD却显著下降.结论 较低中等强度跑台运动能减缓去卵巢大鼠股骨近端和远端骨矿物含量和骨密度的下降;而较高中等强度跑台运动却能加速去卵巢大鼠胫骨近端骨矿物含量和骨密度的下降.     

High-intensity exercise in female athletes: effects on bone mass and body composition

Abstract We investigated bone mass and body composition in young healthy athletic women in order to determine the influence of high-impact physical activity on bone, fat and lean mass. In a case-control study, we studied 68 healthy women, aged 18–45 years, divided in two groups (age and body mass index matched): 39 sedentary women and 29 professional karate athletes. Family and medical histories and information on habits and dietary patterns were collected through a self-administered questionnaire. Bone mineral density (BMD, g/cm²) of whole body, lumbar spine and proximal femur was measured by means of dual energy X-ray absorptiometry (Hologic QDR 4500A scanner; Hologic,Waltham, USA; version 8.26). Total and subregional fat and lean whole body masses were also measured (grams). Significantly higher femoral and total body bone masses were found in active women compared to sedentary women (total femur: 1.00±0.09 vs. 0.95±0.10 g/cm², p<0.05; femoral neck: 0.94±0.11 vs. 0.87±0.11, p<0.05; trochanter: 0.77±0.10 vs. 0.70±0.08, p=0.002; intertrochanter: 1.17±0.09 vs. 1.11±0.12, p<0.05; total body: 1.19±0.06 vs. 1.14±0.08, p<0.05). Active women also had lower fat mass (total: 16510±4430 vs. 20736±7883 g, p=0.007; limbs: 9952±2779 vs. 11888±4147, p=0.027; trunk: 5807±1970 vs. 8325±4113 p=0.001) and higher limb lean mass (15574±2124 vs. 14532±2034 g, p=0.05). A significantly lower calcium intake was registered in active women. Oral contraceptive use appeared to significantly increase femoral bone density. Physical activity increased bone mass in young active women, and this effect seemed to be superior to that of dietary calcium intake.     

小鼠骨组织形态学特征及泼尼松对骨量及骨钙的影响

目的探讨小鼠骨组织形态学和小鼠骨钙含量的研究方法,并观察不同剂量的泼尼松对小鼠骨形态学及骨钙含量的影响.方法 24只昆明种♀小鼠,随机分为4组正常对照组,泼尼松低、中、高剂量组,对照组给予生理盐水,其余3组分别按泼尼松0.75、1.5、6.3 mg.kg-1@d-1灌胃给药,实验21 d后,眼眶放血,取右胫骨进行硬组织包埋切片,作骨组织形态计量学检测,取右股骨测骨钙含量.结果小鼠骨形态学与大鼠相似,但松质骨骨量个体差异大.形态学中骨量与骨钙含量有正相关(P＜0.05).对不同剂量泼尼松作用的检测表明低、高两剂量泼尼松对骨钙含量无明显影响,中剂量可增加骨钙含量(P＜0.05);骨形态计量学观察可见低、中剂量的泼尼松有增加骨量的趋势,中剂量差异有显著性(P＜0.05),高剂量泼尼松有减少骨量的趋势.中剂量增加松质骨表面双荧光强度(P＜0.05).结论小鼠骨形态学特征和骨钙含量有低的相关关系,泼尼松低的剂量可增加小鼠的骨钙含量、骨量和骨小梁表面荧光,当剂量增加时却有减少骨量和骨表面荧光的作用.提示测定药物对骨钙含量影响在一定程度上反映形态学中骨量的变化,提示若用高剂量泼尼松可致小鼠骨量减少模型.     

Combined intervention of dietary soybean proteins and swim training: effects on bone metabolism in ovariectomized rats

Soybean proteins, a rich source of isoflavones, taken immediately after an ovariectomy prevent bone loss in rats. Exercise-induced stimuli are essential for bone growth. Few studies exist about the combined effects of swim training and soybean protein supplementation on bone metabolism. So, the purpose of this study was to investigate, in 48 female Sprague-Dawley rats (12 weeks old) the effects of an 8-week swim-training regimen (1 h/day, 5 days/week) and dietary soybean proteins (200 g/kg diet) on bone metabolism. Rats were randomly assigned to four groups: (1) ovariectomized fed with a semisynthetic control diet; (2) ovariectomized fed with a soybean protein-enriched semisynthetic diet; (3) ovariectomized trained to exercise and fed with control diet; (4) ovariectomized trained to exercise and fed with a soybean protein diet. Following the treatment period, body weight gain was identical in the four groups. Soybean protein supplementation increased bone calcium content, and reduced plasma osteocalcin values, without significant modification of calcium balance and net calcium absorption. Swim training enhanced plasma and bone calcium content and calcium balance and net calcium absorption. It did not modify either plasma osteocalcin values or urinary deoxypyridinoline excretion. Both exercise and soybean protein intake increased plasma on bone calcium without modifying net calcium absorption or bone markers. In conclusion, we demonstrated, in ovariectomized rats, that swimming exercise and dietary supplementation with soy proteins do not have synergistic effects on calcium metabolism and bone markers.     

雌激素预防性给药对去卵巢大鼠骨和脏器的影响

目的采用双侧卵巢切除术建立绝经后骨质疏松(postmenopausal osteoporosis,PMOP)大鼠模型,探讨雌激素预防性给药对绝经后大鼠骨和脏器的影响。方法将SD大鼠分为假手术(sham-operated,Sham)组、去卵巢(ovariectomized,OVX)组、雌二醇组(β-estradiol-treated OVX,OVX/E2)组。术后第10 d开始皮下注射给药并称量大鼠体重,术后61 d处死大鼠,取脏器和骨,称量脏器重量,计算脏器指数。制备组织切片,进行HE染色。结果组织形态学观察表明,OVX组大鼠的股骨和胫骨均出现骨小梁断裂、间距变大、结构紊乱等骨质疏松症状,而OVX/E2组并未出现明显的发病症状。相较于Sham组,OVX组大鼠子宫内膜固有层中的子宫腺数目增多,腺腔增大,子宫黏膜上皮明显增厚,而OVX/E2组的大鼠子宫形态结构并未发生明显病变。大鼠体重和脏器指数分析表明,摘除卵巢不仅会引起大鼠术后早期的体重增加,还会导致大鼠肝、肺、肾和脾的脏器指数增加,而雌激素预防性给药能一定程度上缓解去卵巢手术引发的脏器指数的异常变化。结论适时进行一定剂量的雌激素给药能够较好地预防绝经后骨质疏松症的发生,为绝经后骨质疏松症的预防和治疗提供参考。     

耐力运动对骨质疏松小鼠骨量、骨形态学及Linc-ROR表达的影响

目的研究长链非编码RNA-linc-ROR在运动预防卵巢切除小鼠骨量丢失、改善骨形态学破坏中的作用。方法 24只3月龄雌性C57BL小鼠随机分为假手术组(Sham)、卵巢切除组(Ovx)、卵巢切运动组(Ex)。Ex小鼠接受8周下坡跑训练,8周后所有小鼠处死,收集血液、骨骼标本检测血清激素(ELISA)、骨密度(bone mineral density,BMD)、骨形态学指标(micro-CT)及相关基因(PCR)与蛋白(Western blot)表达。采用STATA 15软件统计组间差异。结果 Ovx小鼠出现BMD下降,骨体积(bone volume/total volume,BV/TV)、骨小梁厚度(trabecular thickness,Tb.Th)、骨小梁数量(trabecular number,Tb.N)减小,骨小梁间距(trabecular separation,Tb.Sp)增加;运动增加Ovx小鼠BMD、BV/TV、Tb.Th和Tb.N,减少Tb.Sp。相比Ovx组,Ex小鼠骨组织中碱性磷酸酶阳性(alkaline phosphatase positive,ALP~+)成骨细胞数量增多。Ovx小鼠血清雌二醇(estradiol,E_2)、骨保护素(osteoprotegerin,OPG)下降,核因子κB受体配体(receptor activator of NF-κB ligand,RANKL)升高,运动明显增加血清E_2、OPG水平,降低RANKL浓度。Ovx小鼠骨组织Linc-ROR及Wnt3、β-catenin mRNA和蛋白表达下降,运动上调这些基因、蛋白的表达。结论耐力运动可预防骨质疏松小鼠骨量丢失、改善骨微观结构,Linc-ROR/Wnt/β-catenin信号通路可能参与这一过程。