Pulsed electromagnetic field stimulation of bone marrow cells derived from ovariectomized rats affects osteoclast formation and local factor production

This study examined the effects of a specific pulsed electromagnetic field (PEMF) stimulation on osteoclast formation in bone marrow cells from ovariectomized rats and to determine if the signal modulates the production of cytokines associated with osteoclast formation. Adult female Wistar rats were subjected to bilateral or sham ovariectomy, and primary bone marrow cells were harvested at 4 days (Subgroup I) and 7 days (Subgroup II) after surgery. Primary bone marrow cells were subsequently placed in chamber slides and set inside solenoids powered by a pulse generator (300 micros, 7.5 Hz) for 1 h per day for 9 days (OVX + PEMF group). Others (INT, SHAM, and OVX groups) were cultured under identical conditions, but no signal was applied. Recruitment and authentication of osteoclast-like cells were evaluated by determining multinuclear, tartrate-resistant acid phosphatase (TRAP) positive cells on day 10 of culture and by pit formation assay, respectively. The PEMF signal caused significant reductions in osteoclast formation in both Subgroups I (-55%) and II (-43%). Tumor necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta), and interleukin 6 (IL-6) in OVX + PEMF group of Subgroup I were significantly reduced at 5, 7, and 9 days as compared to OVX group. The results found in this study suggest that osteoclastogenesis can be inhibited by PEMF stimulation, putatively due to a concomitant decrease in local factor production. Bioelectromagnetics 25:134-141, 2004.     

Pulsed Electromagnetic Fields Improve Bone Microstructure and Strength in Ovariectomized Rats through a Wnt/Lrp5/β-Catenin Signaling-Associated Mechanism

Growing evidence has demonstrated that pulsed electromagnetic field (PEMF), as an alternative noninvasive method, could promote remarkable in vivo and in vitro osteogenesis. However, the exact mechanism of PEMF on osteopenia/osteoporosis is still poorly understood, which further limits the extensive clinical application of PEMF. In the present study, the efficiency of PEMF on osteoporotic bone microarchitecture and bone quality together with its associated signaling pathway mechanisms was systematically investigated in ovariectomized (OVX) rats. Thirty rats were equally assigned to the Control, OVX and OVX+PEMF groups. The OVX+PEMF group was subjected to daily 8-hour PEMF exposure with 15 Hz, 2.4 mT (peak value). After 10 weeks, the OVX+PEMF group exhibited significantly improved bone mass and bone architecture, evidenced by increased BMD, Tb.N, Tb.Th and BV/TV, and suppressed Tb.Sp and SMI levels in the MicroCT analysis. Three-point bending test suggests that PEMF attenuated the biomechanical strength deterioration of the OVX rat femora, evidenced by increased maximum load and elastic modulus. RT-PCR analysis demonstrated that PEMF exposure significantly promoted the overall gene expressions of Wnt1, LRP5 and β-catenin in the canonical Wnt signaling, but did not exhibit obvious impact on either RANKL or RANK gene expressions. Together, our present findings highlight that PEMF attenuated OVX-induced deterioration of bone microarchitecture and strength in rats by promoting the activation of Wnt/LRP5/β-catenin signaling rather than by inhibiting RANKL-RANK signaling. This study enriches our basic knowledge to the osteogenetic activity of PEMF, and may lead to more efficient and scientific clinical application of PEMF in inhibiting osteopenia/osteoporosis.     

Pulsed electromagnetic fields stimulation affects BMD and local factor production of rats with disuse osteoporosis

Pulsed electromagnetic fields (PEMF) have been used widely to treat nonunion fractures and related problems in bone healing, as a biological and physical method. With the use of Helmholtz coils and PEMF stimulators to generate uniform time‐varying electromagnetic fields, the effects of extremely low frequency electromagnetic fields on bone mineral density (BMD) and local factor production in disuse osteoporosis (DOP) rats were investigated. Eighty 4‐month‐old female Sprague Dawley (SD) rats were randomly divided into intact (INT) group, DOP group, calcitonin‐treated (CT) group, and PEMF stimulation group. The right hindlimbs of all the rats were immobilized by tibia‐tail fixation except for those rats in the INT group. Rats in the CT group were injected with calcitonin (2 IU/kg, i.p., once a day) and rats in the PEMF group were irradiated with PEMF immediately postoperative. The BMD, serum transforming growth factor‐beta 1 (TGF‐β1), and interleukin‐6 (IL‐6) concentration of the proximal femur were measured 1, 2, 4, and 8 weeks after treatment. Compared with the CT and DOP groups, the BMD and serum TGF‐β1 concentration in the PEMF group increased significantly after 8 weeks. The IL‐6 concentration in the DOP group was elevated significantly after operation. The PEMF group showed significantly lower IL‐6 level than the DOP group. The results found demonstrate that PEMF stimulation can efficiently suppress bone mass loss. We, therefore, conclude that PEMF may affect bone remodeling process through promoting TGF‐β1 secretion and inhibiting IL‐6 expression. Bioelectromagnetics 31:113–119, 2010. © 2009 Wiley‐Liss, Inc.     

PEMF对废用性骨质疏松大鼠骨形态及骨代谢作用的观察

目的:观察脉冲电磁场(pulsed electromagnetic fields,PEMF)对于废用性骨质疏松(disuse osteoporosis,DOP)大鼠骨形态学及血清学指标的影响,探讨PEMF治疗废用性骨质疏松的作用及其可能的机制。方法:选择雌性SD大鼠,体重250~280 g,随机分为4组,即正常对照组(INT组)、废用模型组(DOP组)、药物治疗组(ALN组)、脉冲电磁场组(PEMF组),每组20只,除正常对照组外,其余大鼠通过改良胫骨-尾部固定法制动建立模型废用性骨质疏松模型,ALN组大鼠灌胃予以阿仑膦酸钠(1 mg·kg-1·d-1)治疗,PEMF组大鼠予以PEMF照射40 min·d-1治疗,治疗后2、4、8、12周时检测各组大鼠的血清学指标并观察其骨组织形态学。结果:治疗2周后,与INT组比较,其余各组血清钙无明显差异,血磷明显降低(P0.05或P0.01),骨钙素(BGP)、碱性磷酸酶(ALT)、抗酒石酸磷酸酶(TRAP)则显著升高(P0.01)。治疗4周后,与ALN组比较,PEMF组BGP、ALT显著升高(P0.01);ALN组骨小梁排列比较DOP组紧密,整齐,骨小梁间隔较大,网状结构断裂程度较轻。治疗8周后,与DOP组比较,余组ALP、TRAP降低(P0.01),与ALN组相较,PEMF组BGP、ALT显著升高(P0.01)。治疗12周后,与DOP组比较,余组BGP、ALP、TRAP降低(P0.05或P0.01),与药物治疗组相较,PEMF组BGP、ALT、TRAP显著升高(P0.05或P0.01)。PEMF组比较ALN组,骨小梁排列整齐有序,骨小梁数目增多,网状结构完整,骨小梁体积增大,厚度增厚。结论:PEMF通过增强成骨细胞功能促进骨形成,同时降低破骨细胞抑制骨吸收,可达到治疗废用性骨质疏松疾病的作用。     

Constructive effect of exogenous melatonin against osteoporosis after ovariectomy in rats

OBJECTIVE: To analyze histomorphometric, densitometric and biochemical effects of melatonin on osteoporosis in ovariectomized rats. STUDY DESIGN: Wistar rats were divided into 6 groups. Group C: control; Group I: bilateral ovariectomy (OVX); Group II: OVX + vehicle; Group III: OVX + 10 mg/kg/day melatonin (MLT); Group IV: OVX + 30 mg/kg/day MLT; Group V: sham + 10 mg/kg/day MLT. Cortex, trabecula, osteoblast and osteoclast numbers were evaluated on vertebra and femur histomorphometrically. Hydroxyproline analysis was used to determine collagen content of femur and vertebrae. Bone mineral density and bone mineral content were measured. RESULTS: Trabecular thickness and trabecular area of vertebra and femur and cortical thickness of femur showed remarkable decrease after OVX, but increased after MLT treatment in the OVX+MLT groups. Following OVX, no statistically significant difference was found in number of osteoblasts or osteoclasts, trabecular number or levels of hydroxyproline after treatment with MLT. OVX caused significant decrease in bone mineral density, but treatment with MLT was unable to reverse this effect. CONCLUSION: MLT may trigger microscopic changes in bone, and time of application is critical for clinical recovery. It can be effective in helping treat postmenopausal osteoporosis. However, it is contraindicated in women who have normal-functioning ovaries.     

降钙素对骨质疏松大鼠骨密度形态计量学与骨代谢的影响

目的探讨降钙素(密盖息)对骨质疏松大鼠骨密度、骨形态计量学影响以及与血钙、磷、维生素D代谢和生长因子的关系。方法用摘除大鼠双侧卵巢的方式制备骨质疏松模型(OVX),实验动物分为4个组:模型对照组、密盖息治疗组,盐酸雷洛昔芬治疗组,假手术组。应用HOLOGIC第4代双能X线4500W骨密度仪测定大鼠腰椎、股骨上段骨密度值(BMD);以骨形态计量学测股骨骨小梁面积、矿化沉积率;用ELISA法测定血清IGF-1水平和血清25OHVitD浓度以及血淋巴细胞维生素D受体(VDR)含量。结果密盖息治疗组、盐酸雷洛昔芬治疗组均较OVX组腰椎、股骨上段骨密度增高,组间比较差异有显著性(P<0.01)。密盖息治疗组较盐酸雷洛昔芬治疗组股骨上段骨密度增高,两组之间差异有显著性(P<0.01)。密盖息治疗组骨小梁面积明显增加、矿化沉积率增高。密盖息治疗组、盐酸雷洛昔芬治疗组血清IGF-1浓度值、血清25-OHVitD浓度值升高,与OVX组比较差异有显著性(P<0.01)。各组血淋巴细胞VDR含量无明显变化,与OVX组比较差异无显著性(P>0.05)。结论密盖息能够预防腰椎、股骨上段骨密度丢失,使骨小梁面积明显增加、矿化沉积率增高并且血清IGF-1及血清25-OHVitD浓度值升高,但对VDR含量无明显作用。     

动态观察去卵巢骨质疏松大鼠股骨骨微结构的变化

目的:绝经后骨质疏松是好发于中老年女性人群中的骨代谢疾病,去卵巢骨质疏松大鼠模型是国内外通用的模拟绝经后骨质疏松发生的经典动物模型,本研究通过观察去卵巢骨质疏松大鼠股骨骨微结构的动态变化,为骨质疏松大鼠模型的临床应用提供理论参考依据。方法:将90只3月龄雌性SD大鼠按体重分层后随机分为基础组(10只)、假手术组(40只)和去卵巢组(40只)。分别在手术前(基础组)和后的3、6、12、24周,腹主动脉取血处死基础组以及假手术组和去卵巢组大鼠,每组各8-10只。每组中随机取6只大鼠,对其左股骨行micro-CT扫描及三维结构重建。选择股骨远端距生长板远端1 mm处,2.0 mm×3.5 mm,厚0.9 mm的骨组织为感兴趣区域,对感兴趣区域进行骨形态计量学分析。结果:与0周组比较,从去卵巢3周开始一直持续到24周,去卵巢组大鼠股骨vBMD、BV/TV和Tb.N显著降低,Tb.Sp和SMI显著升高,而Tb.Th无显著变化;与0周组比较,从假手术后3周开始一直到24周,假手术组所有检测指标均无显著变化。与同周龄假手术组比较,从去卵巢3周开始一直持续到24周,去卵巢组大鼠股骨Tb.N、BV/TV和vBMD显著降低,Tb.Sp显著升高,而Tb.Th没有显著变化。从去卵巢6周开始一直到24周,去卵巢组大鼠SMI显著增加。结论:3月龄大鼠股骨远端的骨微结构在去卵巢3周时就出现显著变化。提示,采用3月龄大鼠进行抗骨质疏松药物筛选时,去卵巢3周后就可以进行药物处理。     

Rolipram, a phosphodiesterase 4 inhibitor, prevented cancellous and cortical bone loss by inhibiting endosteal bone resorption and maintaining the elevated periosteal bone formation in adult ovariectomized rats

Cyclic AMP (cAMP) is a continually produced nucleotide inactivated by hydrolysis to 5'AMP via phosphodiesterase (PDE) enzymes. Rolipram is a selective PDE4 inhibitor reported to have anti-inflammatory effects and used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). The current study was designed to determine whether Rolipram could prevent and restore bone loss in ovariectomized (OVX) rats. Six-month-old Sprague Dawley rats underwent either sham-operated or bilateral ovariectomy, and were left untreated for 60 days to develop osteopenia. Then they were treated with vehicle, 6 mg/kg PGE(2), 3 microg/kg Alendronate or 0.1-1.0 mg/kg Rolipram for 60 days. At sacrifice, the right tibiae were processed for quantitative bone histomorphometric measurements. The right femurs were measured by dual energy A-ray absorptiometry and the 5th lumbar vertebrae were subjected to micro-computed tomography to access bone mass and architecture changes. Our results indicated that OVX induced negative bone balance in all five bone sites we tested, with bone resorption exceeding bone formation. Rolipram at 0.1-0.6 mg/kg dose levels prevented while at 1 mg/kg restored ovariectomy-induced cancellous and cortical bone loss in the tibia, femur and lumbar vertebra. Dynamic bone histomorphometry suggested that these beneficial effects were achieved by partially maintaining the elevated bone formation at the trabecular bone surface and increasing bone formation at the periosteal bone surface of the cortex. Furthermore, it reduced bone turnover at the trabecular and the endocortical bone surfaces. The prevention of further bone loss effects were comparable to those of an anti-resorption agent (Alendronate) but were not as great as those of an anabolic agent (PGE(2)). In addition, Rolipram treatment increased body and muscle weights compared to the vehicle-treated OVX rats. In conclusion, our study in an osteopenic rat model suggested that a selective PDE4 inhibitor may be used for the treatment of established osteoporosis.     

阿司匹林对去势大鼠腰椎骨密度及微观结构的影响

目的:研究阿司匹林对去势(卵巢切除)大鼠腰椎骨密度及微观结构的影响。方法:取48只3月龄SD雌性大鼠随机分为6组:去势组(OVX组)、对照组(Sham组)及4个阿司匹林治疗组(Aspirin组),每组8只。OVX组及Aspirin组采用卵巢切除法建立骨质疏松模型。去势后1周,阿司匹林治疗组剂量分别为2.25、4.46、8.92及26.75 mg/kg(A1、A2、A3及A4组),每天灌胃一次,OVX组及Sham组予同等量生理盐水灌胃。灌胃3个月后处死,剖取腰椎椎体,以双能X线吸收骨密度测量仪(DXA)和Micro-CT进行测量分析。结果:DXA分析结果显示:阿司匹林各剂量组BMD值较OVX组有统计学差异(P<0.01)。Micro-CT分析表明:与OVX组比较,阿司匹林各剂量组BV/TV、Tb.Th、Tb.N、BMD均显著性提高(P<0.01),BS/BV、Tb.Sp显著性降低(P<0.01),阿司匹林各剂量组BV/TV、BS/BV、Tb.Th、Tb.N、Tb.Sp、BMD与Sham组相比有统计学差异(P<0.01)。结论:阿司匹林可以改善去势大鼠骨小梁结构,增加骨质密度,对去势大鼠骨质疏松具有防治作用,其作用途径可能包括抑制骨吸收和刺激骨形成两方面。     

去卵巢致骨质疏松症大鼠腺垂体FS细胞中Cx43、S-100蛋白表达--激光扫描共聚焦显微镜观察

检测间隙连接蛋白Cx43、神经组织蛋白S-100在去卵巢致骨质疏松症(OVX-OP)大鼠腺垂体滤泡星形细胞(FS细胞)中的表达.实验采用10月龄未孕产SD雌性大鼠40只,随机均分为卵巢切除组(OVX组,n=20)和假性手术对照组(Sham组,n=20).于术后6周末用双能X线骨吸收测量法(DEXA)测量大鼠全身及腰椎4-6(L4-6)骨密度(BMD).取两组大鼠垂体,制成连续切片.应用FITC标记的IgG探针,对腺垂体组织中Cx43和S-100进行间接免疫荧光染色,并用激光扫描共聚焦显微镜(LSCM)定位和定量分析腺垂体FS细胞中Cx43、S-100的表达.结果发现,术后6周末OVX组大鼠全身及L4-6BMD均明显低于Sham组值(P<0.01,P<0.01).Cx43阳性荧光反应主要定位于相邻的FS细胞的胞浆中和/或胞膜上.OVX组Cx43阳性表达荧光强度和表达阳性率均显著低于Sham组(P<0.01).S-100蛋白表达定位于FS细胞的胞浆中,两组间S-100阳性表达荧光强度和表达阳性率无显著差异(P>0.05).本研究提示,SD大鼠OVX术后6周出现骨质疏松变化;OVX大鼠腺垂体FS细胞数量无明显变化、而Cx43表达显著下降,后者的变化可能与大鼠OVX-OP发生相关.     

Combined Effects of Phytoestrogen Genistein and Silicon on Ovariectomy-Induced Bone Loss in Rat

This study was performed to evaluate the effect of concomitant supplementation of genistein and silicon on bone mineral density and bone metabolism-related markers in ovariectomized rat. Three-month-old Sprague Dawley female rats were subjected to bilateral ovariectomy (OVX) or sham surgery, and then the OVX rats were randomly divided into four groups: OVX-GEN, OVX-Si, OVX-GEN-Si, and OVX. Genistein and silicon supplementation was started immediately after OVX and continued for 10 weeks. In the OVX-GEN group, 5 mg genistein per gram body weight was injected subcutaneously. The OVX-Si group was given soluble silicon daily in demineralized water (Si 20 mg/kg body weight/day). The OVX-GEN-Si group was given subcutaneous injections of 5 mg genistein per gram body weight, at the same time, given soluble silicon daily (Si 20 mg/kg body weight/day). The results showed that the genistein supplementation in the OVX rats significantly prevented the loss of uterus weight; however, the silicon supplementation showed no effect on the uterus weight loss. The lumbar spine and femur bone mineral density was significantly decreased after OVX surgery; however, this decrease was inhibited by the genistein and/or silicon, and the BMD of the lumbar spine and femur was the highest in the OVX-GEN-Si-treated group. Histomorphometric analyses showed that the supplementation of genistein and/or silicon restored bone volume and trabecular thickness of femoral trabecular bone in the OVX group. Besides, the treatment with genistein and silicon for 10 weeks increased the serum levels of calcium and phosphorus in the OVX rats; serum calcium and serum phosphorus in the OVX-GEN-Si group were higher than those in the OVX-GEN and OVX-Si group (P < 0.05). At the same time, the treatment with genistein and/or silicon decreased serum alkaline phosphatase (ALP) and osteocalcin, which were increased by ovariectomy; serum ALP and osteocalcin in the OVX-GEN-Si group were lower than those in the OVX-GEN and OVX-Si groups (P < 0.05). The results above indicate that genistein and silicon have synergistic effects on bone formation in ovariectomized rats.     

Role of recombinant plasmid pEGFP-N1-IGF-1 transfection in alleviating osteoporosis in ovariectomized rats

Decreased levels of serum insulin-like growth factor-1 (IGF-1) have been proven to cause osteoporosis. Gene transfer of IGF-1 offers an attractive technology to treat skeletal metabolic disorders including osteoporosis, but the viral vectors are limited by their high antigenicity and immune response. Our purpose was to investigate the expression of a non-invasive vector, recombinant plasmid enhanced green fluorescent protein-N1 (pEGFP-N1) that transferred IGF-1 gene into ovariectomized (OVX) rats in vivo and evaluate the effect of this therapy on osteoporosis. OVX or sham operations were performed in 60 female, 7-month-old unmated SD rats. 12 weeks after OVX operation, the vectors were transfected to the 10-month-old rats and experimental data were detected from 48 h to 7 week after transfection. Our results showed that remarkable expression of fluorescence and serum IGF-1 was observed in the rats transfected by recombinant plasmids, indicating that IGF-1 gene was successfully transferred to OVX rats by injecting the vector through hydrodynamic method via the tail vein. The bone metabolism index including serum alkaline phosphatase, the histomorphometric parameters of lumbar vertebra including trabecular area percentage, trabecular thickness, trabecular number and trabecular separation, and the bone mineral density (BMD) and biomechanical parameters of lumbar vertebra including BMD, maximum condensing force, crushing strength in OVX rats transfected by pEGFP-N1-IGF-1 were improved remarkably compared with OVX+pEGFP-N1 rats, indicating that the transfection of recombinant plasmid pEGFP-N1-IGF-1 played a significant role in alleviating osteoporosis in rats induced by OVX. This encouraged a potential approach of IGF-1 gene therapy to the treatment of osteoporosis.     

Beneficial effects of losartan on vascular injury induced by advanced glycosylation end products and their receptors in spontaneous hypertension rats

The purpose of this study was to examine the effects of ENA Actimineral Resource A (ENA-A), seaweed origin alkaline water, on postmenopausal osteoporosis in ovariectomized (OVX) rats. The 12-week old Wistar rats were divided randomly into 4 groups: ovariectomized (OVX), OVX plus 0.5% ENA-A, OVX plus 5% ENA-A and OVX plus 10% ENA-A. A histopathological analysis indicated that ENA-A could prevent OVX-induced bone loss by increasing femur trabecular bone area in a dose-dependent manner. ENA-A significantly (p < 0.05) increased serum estradiol levels, decreased serum osteocalcin activity and suppressed serum pyridinoline (PYD) levels. The in vitro effects of ENA-A were also studied using MC3T3-E1 cells. ENA-A significantly stimulated cell proliferation and increased both ALP activity and calcium deposition in a dose-dependent manner. These results suggest that the treatment of ovariectomized rats with ENA-A not only prevents bone resorption but also appears to maintain the cancellous bone structure of postmeopausal osteoporosis.     

Bone loss in ovariectomized rats: dominant role for estrogen but apparently not for FSH

Estrogen deficiency as the sole factor underlying post‐menopausal osteoporosis was challenged, in light of reports that both follicular stimulation hormone (FSH) receptor and FSHβ knockout mice were resistant to bone loss, suggesting a detrimental role for FSH. We assessed whether lowering FSH levels by gonadotropin realizing (GnRH) analog decapeptyl in ovariectomized female rats (OVX) affects bone. Wistar‐derived 25 days old OVX female rats were injected for 10 weeks with estradiol‐17β (E₂), with GnRH analog (decapeptyl) or with both. FSH and luteinizing hormone (LH) serum levels were markedly increased in OVX rats, with smaller growth plates with disrupted architecture; heavy infiltration of bone marrow with numerous adipocytes and reduced thickness of cortical bone. In OVX rats treated with E₂, FSH, and LH levels were intermediate, the tibia was similar to that of intact rats, but there was reduced thickness of cortical bone. In decapeptyl treated OVX rats, FSH and LH levels were suppressed, the organization of growth plate and the trabecular bone were disrupted, and there were fewer proliferative and chondroblastic cells and a large adipocytes population in bone marrow, but an increased trabecular bone volume (TBV). In the E₂ + decapeptyl treatment, FSH and LH levels were suppressed, with partially restored growth plate architecture and improved TBV. In conclusion, E₂ deficiency is the dominant factor impairing bone loss in OVX and concomitant changes in FSH/LH levels achieved by decapeptyl have some modulating, though complex role in this setting. The role of high FSH levels in post‐menopausal bone loss requires further investigation using combined sub‐optimal doses of the different hormones. J. Cell. Biochem. 112: 128–137, 2011. © 2010 Wiley‐Liss, Inc.     

Simvastatin did not prevent nor restore ovariectomy-induced bone loss in adult rats

Current published results on whether statins have beneficial effects on bone metabolism have been conflicting so far. In order to further investigate if statins were promising candidates for the treatment for osteoporosis, we conducted a study in which rats were ovariectomized (OVX) at 6 months of age, allowed to lose bone for 60 days and followed by oral administration of simvastatin at the dose levels of 0.3-10 mg/kg/d for 60 days. PGE2 (6 mg/kg) was used as a positive control. Study endpoints included bone histomorphometry on the proximal tibial metaphysis (PTM) and the tibial diaphysis (TX), dual-energy X-ray absorptiometry on the right femur and micro computed tomography (ICT) on the 5th lumbar vertebra (LV). After 120 days of OVX, cancellous bone lost by 80% in the PTM and 18% in the LV accompanied by increased bone formation and resorption. Simvastatin at all dose levels did not affect bone volume, bone formation rate and bone erosion surface when compared to 120 day ovariectomized animals at all bone sites studied. By contrast, PGE2 restored cancellous and cortical bone area to sham control levels. In conclusion, this study demonstrated that unlike PGE2, oral administration of simvastatin did not have effects on cancellous or cortical bone formation and resorption; and consequently was not able to prevent further bone loss or restore bone mass in the osteopenic, OVX rats.     

Analysis of Bacteria,Parasites, and Heavy Metals in Lettuce (<Emphasis Type="Italic">Lactuca sativa</Emphasis>) and Rocket Salad (<Emphasis Type="Italic">Eruca sativa</Emphasis> L.) Irrigated with Treated Effluent from a Biological Wastewater Treatment Plant

The purpose of this study was to verify the effect of organic gallium on ovariectomized osteopenic rats. Thirty Wistar female rats used were divided into three groups: (1) sham-operation rats (control), (2) ovariectomized (OVX) rats with osteopenia, and (3) OVX rats with osteopenia treated with organic gallium. Treatments were performed over an 8-week period. At sacrifice, the fifth lumbar vertebral body, one tibia, one femur, and the fourth lumbar vertebrae were removed, subjected to micro-CT for determination of trabecular bone structure, and then processed for histomorphometry to assess bone turnover. The femoral neck was used for mechanical compression testing. Treatment with organic gallium increased bone volume in OVX animals. Organic gallium-treated animals had significant increases in trabecular and cortical thickness and bone strength. The plasma total calcium and inorganic phosphate concentrations in OVX rats decreased and bone mineral content in the lumbar vertebrae and femur increased after treatment with organic gallium. These data provide an important proof of concept that organic gallium may represent a powerful approach to treating or reversing severe osteoporosis in humans.     

Comparison of the Therapeutic Effects of Yeast-incorporated Gallium with those of Inorganic Gallium on Ovariectomized Osteopenic Rats

The purpose of this study was to verify the effect of organic gallium on ovariectomized osteopenic rats. Thirty Wistar female rats used were divided into three groups: (1) sham-operation rats (control), (2) ovariectomized (OVX) rats with osteopenia, and (3) OVX rats with osteopenia treated with organic gallium. Treatments were performed over an 8-week period. At sacrifice, the fifth lumbar vertebral body, one tibia, one femur, and the fourth lumbar vertebrae were removed, subjected to micro-CT for determination of trabecular bone structure, and then processed for histomorphometry to assess bone turnover. The femoral neck was used for mechanical compression testing. Treatment with organic gallium increased bone volume in OVX animals. Organic gallium-treated animals had significant increases in trabecular and cortical thickness and bone strength. The plasma total calcium and inorganic phosphate concentrations in OVX rats decreased and bone mineral content in the lumbar vertebrae and femur increased after treatment with organic gallium. These data provide an important proof of concept that organic gallium may represent a powerful approach to treating or reversing severe osteoporosis in humans.     

A polysaccharide from the dried rhizome of Drynaria fortunei (Kunze) J. Sm. prevents ovariectomized (OVX)-induced osteoporosis in rats

In the present study, a homogenous polysaccharide (DFPW) was isolated and purified from the dried rhizome of Drynaria fortunei, and its protective effect against osteoporosis was investigated in ovariectomized (OVX) rats. Histological analysis indicated that oral administration of DFPW (100 and 400 mg/kg) for 12 weeks significantly improved trabecular bone mass, as demonstrated by the increase in trabecular area, trabecular thickness and its number in OVX rats. Furthermore, the decline of bone mineral density and bone mineral content including Ca, P and Mg induced by OVX was reversed by the DFPW administration. This function was achieved by the decreased levels of the bone turnover markers, such as serum ALP, urinary deoxypyridinoline (DPD), Ca and P excretions. Besides, DFPW improved biomechanical parameters (maximum load, energy, Young's, modulus and maximum stress) to strengthen the hardness and strength femoral diaphysis in OVX rats. These results strongly suggested that DFPW might be a hopeful alternative therapeutics to treat postmenopausal osteoporosis.     

Effect of Low-Magnitude Whole-Body Vibration Combined with Alendronate in Ovariectomized Rats: A Random Controlled Osteoporosis Prevention Study

Background

Alendronate (ALE) is a conventional drug used to treat osteoporosis. Low-magnitude whole-body vibration (WBV) exercise has been developed as a potential treatment for osteoporosis. The aim of this study was to investigate whether low-magnitude WBV could enhance the protective effect of ALE on bone properties in ovariectomized rats.

Methods

A total of 128 Sprague-Dawley rats were randomly divided into five groups (SHAM, OVX+VEH, OVX+WBV, OVX + ALE, OVX+WBV+ALE). The level of WBV applied was 0.3 g at 45–55 Hz for 20 min/day, 5 day/week and for 3 months. ALE was administered in dose of 1 mg/Kg once a week. Every four weeks eight rats from each group were sacrificed and their blood and both tibiae were harvested. The expression of osteocalcin and CTX in serum was measured by enzyme-linked immunosorbent assay (ELISA) and the tibiae were subjected to metaphyseal three-point bending and μCT analysis.

Results

Osteocalcin rose after ovariectomy and was not appreciably changed by either alendronate or WBV alone or in combination. Alendronate treatment significantly prevented an increase in CTX. WBV alone treatment did not alter this effect. Compared with the OVX+WBV group, nearly all tested indices such as the BV/TV, TV apparent, Tb.N, Tb.Th, and Conn.D were higher in the OVX+ALE group at week 12.Compared with the OVX+WBV group, certain tested indices such as BV/TV, TV apparent, Tb.N, and Con.D, were higher in the OVX+WBV+ALE group at week 12. At week 12, tibiae treated with WBV+ALE exhibited a significantly higher F_max compared to the OVX+VEH group, and a significant difference was also found in energy absorption between the OVX+WBV+ALE and OVX+VEH groups.

Conclusions

Compared with the WBV, ALE was more effective at preventing bone loss and improved the trabecular architecture. However, WBV enhanced the effect of alendronate in ovariectomized rats by inducing further improvements in trabecular architecture.     

Biomechanical properties of bones from rats treated with sevelamer

Sevelamer hydrochloride is used for ten years in patients on dialysis as a phosphate binder. We have previously shown that oral application of sevelamer prevents the bone loss and increases the bone volume in ovariectomized rats. In this study we further analysed the biomechanical properties of bones from rats treated with sevelamer utilizing a threepoint bending test to determine the mechanical properties of the cortical bone of the mid-shaft femur, while the indentation test was used to determine the mechanical properties of cancellous bone in the marrow cavity of the distal femoral metaphysis. Parameters analyzed included: maximum load (F(u)), stiffness (S), energy absorbed (W), toughness (T) and ultimate strength (sigma). The intrinsic properties, stress, elastic modulus and toughness were determined from measured maximum load, strains, stiffness, energy absorbed, outer and inner diameters, and calculated bone cross-sectional moment of inertia. Sevelamer was given to rats for 25 weeks with a content of 3% of sevelamer in a standard diet, starting immediately following ovariectomy (OVX). Animals were divided to the following groups: (1) Sham; (2) Sham + sevelamer 3%; (3) OVX; (4) OVX + sevelamer 3%. Our results showed that sevelamer particularly influenced the rat trabecular bone by increasing the maximum load for 26.2%, energy absorbed for 24.2% and the ultimate strength for 26.2% in sham animals treated with sevelamer 3%, as compared to sham rats. Sevelamer 3% in OVX rats also increased the maximum load for 71.4%, stiffness for 70.7%, energy absorbed for 55.9% and the ultimate strength for 71.3% as compared to OVX controls. In the three bending test sevelamer had a very little effect on preventing loss of bone strenght in the cortical bone. These results collectively suggest that sevelamer improves bone biomechanical properties, mainly affecting trabecular bone quality in both normal and ovariectomized rats.