Effect of dietary legumes on bone-specific gene expression in ovariectomized rats

In previous studies, we found that the consumption of legumes decreased bone turnover in ovariectomized rats. The purpose of the present study is to determine whether the protective effects on bone mineral density (BMD) and the microarchitecture of a diet containing legumes are comparable. In addition, we aim to determine their protective actions in bones by studying bone specific gene expression. Forty-two Sprague-Dawley rats are being divided into six groups during the 12 week study: 1) rats that underwent sham operations (Sham), 2) ovariectomized rats fed an AIN-93M diet (OVX), 3) ovariectomized rats fed an AIN-93M diet with soybeans (OVX-S), 4) ovariectomized rats fed an AIN-93M diet with mung beans (OVX-M), 5) ovariectomized rats fed an AIN-93M diet with cowpeas (OVX-C), and 6) ovariectomized rats fed an AIN-93M diet with azuki beans (OVX-A). Consumption of legumes significantly increased BMD of the spine and femur and bone volume of the femur compared to the OVX. Serum calcium and phosphate ratio, osteocalcin, expression of osteoprotegerin (OPG), and the receptor activator of nuclear factor κB ligand (RANKL) ratio increased significantly, while urinary excretion of calcium and deoxypyridinoline and expression of TNF-α and IL-6 were significantly reduced in OVX rats fed legumes, compared to OVX rats that were not fed legumes. This study demonstrates that consumption of legumes has a beneficial effect on bone through modulation of OPG and RANKL expression in ovariectomized rats and that legume consumption can help compensate for an estrogen-deficiency by preventing bone loss induced by ovarian hormone deficiency.     

Soybean isoflavones dose-dependently reduce bone turnover but do not reverse established osteopenia in adult ovariectomized rats

We assessed the dose-dependent effects of daily soybean isoflavone (IF) consumption in reversing bone loss in adult ovariectomized rats. On d 0, female Wistar rats (7 mo old; n = 55) were either sham-operated (SH; n = 14) or ovariectomized (n = 41). On d 80, intermediate rats (SH: n = 5; ovariectomized: n = 5) were killed to confirm the ovariectomy-induced bone loss. The remaining ovariectomized rats were randomly assigned to one of four groups of nine rats each and fed soybean IF (mixed with a soy protein-free semipurified diet) at 0 (OVX), 20 (IF20), 40 (IF40) or 80 (IF80) mg/(kg body. d) for 84 d. Simultaneously, SH rats were fed the semipurified diet without any additional compound and killed on d 164, as were the other rats. As expected, both bone mineral density in the total femur and in its diaphyseal and metaphyseal subregions and cancellous bone area/measured surface in the distal femur metaphysis were lower in OVX than in SH rats (P: < 0.05). OVX rats had higher plasma osteocalcin concentration and urinary deoxypyridinoline excretion than SH rats (P: < 0.05). On d 164, osteocalcin and deoxypyridinoline concentrations were lower in IF40 or IF80 rats than in OVX rats (P: < 0.05). Nevertheless, neither bone mineral density nor cancellous bone area was greater in IF-fed rats than in OVX rats. Therefore, in adult ovariectomized rats, daily soybean IF consumption decreased bone turnover but did not reverse established osteopenia.     

Effects of taurine supplementation on bone mineral density in ovariectomized rats fed calcium deficient diet

Taurine supplementation has been shown to have a beneficial effect on femur bone mineral content in ovariectomized rats. It therefore seemed desirable to find out whether the beneficial effect of taurine on ovariectomized rats fed calcium deficient diet could also be reproduced. Forty female Sprague-Dawley rats were divided into two groups. One group was OVX and the other group received sham operation (SHAM), and received either control diet or a taurine supplemented diet for 6 weeks. All rats were fed on calcium deficient diet (AIN-93: 50% level of calcium) and deionized water. Bone mineral density (BMD) and bone mineral content (BMC) were measured in spine and femur. The serum and urine concentrations of calcium and phosphorus were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. Bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Urinary calcium and phosphorus excretion, osteocalcin in blood and cross link value were not significantly different among the groups. Within the OVX group, the taurine supplemented group had not higher femur bone mineral content than the control group. This study established the need for a study on the taurine effect on bone with different calcium levels.     

A combination of dietary fructooligosaccharides and isoflavone conjugates increases femoral bone mineral density and equol production in ovariectomized mice

Fructooligosaccharides (FOS) stimulate the growth of bifidobacteria, which cleave isoflavone conjugates to yield the corresponding aglycones and metabolites. In a previous study, FOS modified the absorption and enterohepatic recirculation of isoflavones in rats. In the present study, we determined the effect of the combination of dietary FOS and isoflavone conjugates on bone mass in ovariectomized (OVX) and surgical control mice. After undergoing OVX or sham operation, female ddY mice (8 wk old, n = 64) were randomly assigned to four groups: a purified control diet (AIN-93G) group, a FOS diet (AIN-93G + 5% FOS) group, an isoflavone diet (AIN-93G + 0.2% isoflavone conjugates) group, or a FOS and isoflavone diet (AIN-93G + 5% FOS + 0.2% isoflavone conjugates) group. After 6 wk, the mice were killed and the blood and femora were sampled immediately. In OVX mice, both isoflavone conjugates and FOS prevented femoral bone loss. An additive effect of dietary isoflavone conjugates and FOS was observed by dual-energy X-ray absorptiometry in the distal part of the femur and in trabecular bone, by peripheral quantitative computed tomography. Moreover, FOS increased cecal beta-glucosidase activity and equol production from daidzein in both OVX and surgical control mice fed isoflavone conjugates. These results suggest that FOS increase the bioavailability of isoflavones, leading to cooperative effects in the prevention of osteopenia in OVX mice.     

白藜芦醇对去卵巢大鼠骨密度的影响

目的:探讨白藜芦醇(RES)对去卵巢大鼠骨密度(BMD)的影响。方法:48只SD大鼠随机分为6组,分别接受假手术(A)、去卵巢(B)、去卵巢+0.03mg/(kgbw·d)己烯雌酚(DES,C)、去卵巢+RES5、15和45mg/(kgbw·d)(D,E,F)90d后,用双能X线吸收法测定大鼠的骨密度,观察其改变。结果:B组大鼠各BMD测定指标均显著低于A组,D、E、F组全身和腰椎BMD均显著高于B组,E、F组整体股骨BMD显著高于B组。结论:白藜芦醇对去卵巢大鼠的骨丢失有抑制作用,以45mg/(kgbw·d)剂量对骨密度的保护效果最好。     

大豆异黄酮类对去卵巢大鼠骨丢失的影响

目的　研究大豆中植物雌激素——异黄酮类对去卵巢大鼠骨丢失的预防作用。方法　将 3月龄 SD雌性大鼠按体重分为 5组 ,每组 1 1只 :假手术对照组 (假手术 +饲含酪蛋白饲料 ,Sham) ;去异黄酮组 (去卵巢 +饲含去异黄酮类大豆分离蛋白饲料 ,Soy- ) ;异黄酮组 (去卵巢 +饲含异黄酮类大豆分离蛋白饲料 ,Soy+) ;酪蛋白组 (去卵巢 +饲含酪蛋白饲料 ,即去卵巢对照组 ,Ovx) ;雌激素对照组 (去卵巢 +饲含酪蛋白饲料 +注射雌二醇 ,E2 )。在实验期第 3周、第 6期和第 9周各进行为期三天的钙代谢试验。第 1 0周末处死大鼠 ,测定骨钙、骨密度 ,并对股骨远端松质骨进行骨组织形态学测量。结果　异黄酮组和雌激素对照组粪钙、尿钙排出量显著低于酪蛋白组和去异黄酮组 (P<0 .0 5) ,钙表观吸收率和钙贮留量显著高于酪蛋白组和去黄酮组 (P<0 .0 5) ,钙代谢呈正平衡。异黄酮组和雌激素对照组骨钙、骨密度高于酪蛋白组和去异黄酮组 (P<0 .0 5)。与雌激素对照组比较 ,异黄酮组骨小梁面积百分率和骨小梁数目明显减少 ,骨小梁间隙明显增宽 (P<0 .0 5) ;但与酪蛋白组和去异黄酮组比较 ,异黄酮组骨小梁面积百分率和骨小梁数目明显增多 ,骨小梁间隙明显减少 (P<0 .0 5)。结论　含有异黄酮类的大豆分离蛋白具有预防骨丢失的作用 ,而?     

Genistein may prevent cadmium-induced bone loss in ovariectomized rats

This study compared the ability of genistein, a soy isoflavone, with that of 17 beta-estradiol to prevent bone loss in cadmium (Cd)-exposed ovariectomized (OVX) rats during growth. Female Wistar rats (4 weeks old) were either sham-operated (SH; n = 9/group) or OVX and placed on experimental diets (n = 9/group): OVX; OVX rats fed 50 ppm of CdCl(2) (OVX-Cd); OVX fed 50 ppm of CdCl(2) and 10 microg/kg of body weight genistein (OVX-Cd-G); and OVX fed 50 ppm of CdCl(2) and 10 microg/kg of body weight estrogen (OVX-Cd-E). All rats were given free access to AIN-76 modified diet and drinking water, with or without Cd, for 8 weeks. The OVX groups gained more body weight than the SH group. Femoral weight was increased by feeding genistein and estradiol, whereas femoral length among groups was not significantly different. Femoral Cd content was significantly higher in the OVX-Cd group than in the other groups. Both serum osteocalcin and calcium (Ca) concentrations, as well as urinary Ca, were significantly higher in the OVX-Cd group than in the other groups. Urinary excretion of Cd was significantly increased in Cd-OVX-G rats, and fecal Cd excretion was increased by feeding both genistein and estradiol. Femoral histomorpological changes in proliferative cartilage and hypertrophic cells in the OVX-Cd group showed that both cell types were decreased by feeding Cd, and irregular arrangements were observed in proliferative cells. However, both cells types exhibited normal distribution in OVX-Cd-G and OVX-Cd-E groups. These findings suggest that Cd/OVXinduced osteopenia or osteoporosis probably results from an increase in bone turnover. Genistein may be involved in stimulating Cd excretion and inhibiting Ca excretion from bone.     

Changes in Bone Metabolism and Antioxidant Defense Systems in Menopause-Induced Rats Fed Bran Extract from Dark Purple Rice (Oryza sativa L. Cv. Superjami)

Menopause is a matter of concern for women’s health due to a deficiency of female hormones; additionally, reactive oxygen species and aging can cause osteoporosis. Food becomes increasingly interesting as a menopausal woman’s alternative to hormone therapy. The effects of ethanol extracts from dark purple Superjami rice bran on bone metabolism and antioxidant defense systems in menopause-induced animal models were evaluated. Female rats underwent sham surgery or were ovariectomized to induce a menopause-like state. Rats were divided into a sham control group (SHAM), an ovariectomized control group (OVX), and an ovariectomized grou supplemented with Superjami rice bran extract group (OVX-S) and fed for 8 weeks. The OVX groups exhibited significantly more weight gain, amounts of bone turnover biochemical markers (alkaline phosphatase, osteocalcin, and C-terminal telopeptide), bone loss, lipid-peroxidation and oxidative stress than the SHAM group. However, Superjami bran extract added to the diet resulted in a significant reduction in body weight and lipid peroxidation, as well as enhanced bone metabolism and antioxidant enzyme activities, in ovariectomized rats. These results propound that extracts from Superjami rice bran have therapeutic potentiality against bone loss and oxidative stress in menopause-induced states and will be useful in preventing postmenopausal osteoporosis and oxidative damage.     

运动对去卵巢大鼠骨矿含量和骨密度的影响

目的观察运动对去卵巢大鼠骨矿含量（bone mineral contant,简称BMC）和骨密度（bone mineral den-sity,简称BMD）的影响。方法雌性（sprague daivley,简称SD）大鼠随机分为正常对照组（SHAM）、去卵巢手术对照组（OVX）、雌激素治疗组（OVX＋ES）、运动组（OVX＋ET）。SHAM组行假手术,其余各组行双侧卵巢切除术,术后75天开始为期3个月的治疗。OVX＋ES组用尼尔雌醇治疗,OVX＋ET组按要求进行运动。治疗结束后检测股骨和胫骨的BMC和BMD。结果股骨BMD比较,SHAM组（0．206±0．009）高于OVX组（0．196±0．012）,差异有统计学意义（P〈0．05）;胫骨BMC比较,OVX＋ET组（0．298士0．033）高于OVX组（0．260±0．033）,差异有统计学意义（P〈0．05）;胫骨BMD比较,0VX组比其它3组均低,差异有统计学意义（P〈0．05或P〈0．01）;运动明显提高去卵巢大鼠胫骨的BMC和BMD,运动在提高胫骨BMD方面的功效优干激素疗法．结诊运动对绝经后骨盾疏凇症的形成有一定干预作用。     

大豆异黄酮对去势大鼠骨量丢失的抑制作用研究

目的:研究大豆异黄酮(Soybeanisoflavone,SI)对去势后大鼠由于体内雌激素水平下降引起的骨量丢失的抑制作用。方法:腹腔手术切除大鼠双侧卵巢,分为对照组、SI组和雌激素对照组,并设假手术对照组,喂养16w后,测定雌二醇、骨生化指标、骨密度、骨钙、骨磷等指标,扫描电镜和组化分析观察骨小梁微观结构的变化。结果:SI显著降低血清中骨吸收指标TRAP活性,同时明显提高骨形成指标BGP含量;SI具有弱雌激素作用,可抑制去卵巢大鼠体内雌激素水平的下降,骨密度和骨钙、骨磷含量增加,松质骨的骨丢失得到抑制。结论:SI可降低骨吸收、促进骨形成,对去卵巢引起的骨量丢失有明显的抑制作用。     

运动与复方丹参合剂联合应用对去卵巢大鼠骨矿盐代谢的影响

用测定骨矿盐含量的方法,观察运动和复方丹参合剂(compound Danshen mixture,CDM)联合应用对去卵巢大鼠骨矿盐代谢的影响。将健康4月龄雌性Sprague-Dawley(SD)大鼠48只,按体重随机分成6组:正常对照组;假去卵巢组;去卵巢组;去卵巢+CDM组;去卵巢+运动组;去卵巢+CDM+运动组。去卵巢+CDM组和去卵巢+CDM+运动组大鼠于去卵巢手术后第2 d开始给予CDM溶液灌胃,10 ml/(kg·d),持续11周。去卵巢+运动组和去卵巢+CDM+运动组大鼠于去卵巢术后第7 d开始给予中等强度的运动训练,每周5 d,每天连续匀速跑45 min,16 m/min,跑道倾角0°,持续10周。结果表明,去卵巢组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重占骨干重百分比等指标均低于假去卵巢组(P0.01);去卵巢+复方丹参合剂组和去卵巢+运动组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重占骨干重百分比等指标虽然较去卵巢组增加(P0.05或P0.01),但仍低于假去卵巢组(P0.05或P0.01);去卵巢+复方丹参合剂+运动组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重占骨干重百分比等指标均高于去卵巢+复方丹参合剂组和去卵巢+运动组(P0.05或P0.01)。提示运动可加强复方丹参合剂抗去卵巢大鼠骨矿盐丢失的作用。     

运动加强氟化钠对去卵巢大鼠骨矿盐代谢的影响效应

用测定骨矿盐含量的方法,观察运动对氟化钠(NaF)抗去卵巢大鼠骨矿盐丢失的影响效应。将健康4月龄雌性SD大鼠30只,用抽签法随机分成5组:正常对照组;假去卵巢组;去卵巢组;去卵巢+NaF组;去卵巢+NaF+运动组。去卵巢+NaF组和去卵巢+NaF+运动组大鼠于去卵巢手术后第2 d开始给予NaF溶液灌胃,0.5 mg/(kg.BW),1次/d,持续11周。去卵巢+NaF+运动组于去卵巢术后第7 d开始运动训练,每周5 d,每天连续匀速跑45 min,16 m/min,跑道倾角0°,持续10周。结果表明,去卵巢组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重/骨干重(%)均明显低于假去卵巢组;去卵巢+NaF组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重/骨干重(%)等指标虽然较去卵巢组增加,但仍显著低于假去卵巢组;NaF半量与运动联合应用后,上述各指标均显著回升,并且基本恢复到对照组水平。提示运动可加强NaF抗去卵巢大鼠骨矿物盐丢失的作用。     

雌激素和维生素K抗去势成年雌性大鼠骨质疏松的实验研究

目的寻找一种或一组简便有效,价格低廉的防治骨质疏松（osteoporosis,OP）的方法,以期为防治骨质疏松药物的开发提供实验依据。方法以去卵巢雌性SD大鼠作为绝经早期骨质疏松模型。将50只SD雌性大鼠随机分为5组：卵巢去势（ovariectomized,OVX）组（OVX组,n=10）、卵巢去势＋雌激素组（OVX＋E组,n=10）、卵巢去势＋维生素K组（OVX＋vit K组,n=10）和卵巢去势＋雌激素＋维生素K组（OVX＋E＋vitK组,n=10）、假手术组（sham组,n=10）。卵巢去势1个月后,分组给药,8周后集中统一处死,取左侧股骨检测骨密度（bone mineral density,BMD）,右侧股骨病理学切片进行骨小梁形态计量观察,取右心室血清检测白介素（interleukin,IL）-6、骨钙素（bone gla protein,BGP）和胰岛索样生长因子（insulin-like growth factor,IGF）-1含量。结果①OVX组与sham组比较,骨密度显著下降,血清白介素-6和骨钙素测量值明显升高,而胰岛素生长因子-1显著下降,表明造模成功。②OVX组骨组织病理学切片40倍光镜下骨小梁形态计量观察结果与sham组、OVX＋vitK组、OVX＋E组和OVX＋E＋vit K组比较,差异有显著意义。其中,OVX＋E＋vit K组与sham组最相似。③OVX＋E组与OVX组比较,股骨干骺端（松质骨）骨密度显著升高,而股骨中段（皮质骨为主）骨密度升高,差异无显著意义。OVX＋vitK组与OVX组比较,股骨中段（皮质骨）骨密度显著升高,股骨干骺端（松质骨为主）骨密度升高,但差异无显著意义。OVX＋E＋vitK组股骨干骺端和股骨中段骨密度均显著性升高,与sham组最接近。④OVX＋E组与OVX组比较,血清白介素-6含量和骨密度低,胰岛素生长因子-1含量升高,差异有显著意义;OVX＋vitK组与OVX组比较,血清白介素-6测量值低,骨钙素和胰岛素生长因子-1测量值升高,差异有显著意义;OVX＋E＋vitK组血清白介素-6,骨钙素和胰岛素生长因子-1含量与sham组比较,最为接近。结论①去卵巢大鼠骨密度及骨形成指标胰岛素生长因子-1下降,骨吸收指标白介素-6、骨吸收和骨形成指标骨钙素升高,表明绝经早期骨代谢处于骨吸收大于骨形成的高转换状态,导致骨质疏松。②雌二醇（estrogen,E2）水平下降是骨质疏松的一个重要致病因素。病理形态学观察和骨密度及血清白介素-6、骨钙素、胰岛素生长因子-1含量检测表明,维生素K和雌激素防治骨质疏松均有效,二者联合用药的作用明显优于单一用药。     

Fermented soybeans by Rhizopus oligosporus reduce femoral bone loss in ovariectomized rats

BACKGROUND/OBJECTIVES

Soy isoflavones are structurally similar to estrogen and bind to estrogen receptors, suggesting that they exhibit estrogenic activities; therefore, they are referred to as phytoestrogens. Fermentation may affect the bioavailability of isoflavones altering soy isoflavone glycosides in the form of aglycones. Thus, this study investigated the effects of fermented soybeans by Rhizopus oligosporus on bone metabolism in both young rats as a pilot test and in ovariectomized (ovx) old rats as a model of menopause.

MATERIALS/METHODS

In the pilot test, a total of 24 seven-week-old female Sprague-Dawley (SD) rats were fed one of three diets for a period of four weeks: casein, unfermented soybean product, or fermented soybean product by R. oligosporus. In the ovx rat model, 20-week-old SD rats weighing 260-290 g underwent either sham-operation (n = 10) or bilateral ovariectomy (n = 30) and were then fed the AIN-93M diet for one week. Thereafter, rats were fed sham-casein, ovx-casein, ovx-soybean, or ovx-fermented soybean diet for five weeks. After decapitation, femoral bones were isolated and preserved in 9% formalin for assessment of bone mineral density (BMD), bone mineral content (BMC), and bone-breaking strength (BBS).

RESULTS

Ovx rats showed significantly increased weight gain and decreased uterine wet weight. Of particular interest, ovx rats fed fermented soybeans showed increased uterine wet weights compared to control rats. Fermented soybean diet caused a significant increase in plasma 17-β estradiol concentrations in young rats, and 17-β estradiol levels were enhanced in ovx rats to match those of sham-operated ones. Significantly lower femoral BMD and BMC were observed in ovx rats compared to sham-operated controls, whereas bone areas did not differ statistically among the groups. In addition, BBS tended to be increased in ovx rats fed soybeans and fermented soybeans.

CONCLUSIONS

Supplementation of fermented soybeans could have preventive and therapeutic effects against osteoporosis in postmenopausal women.     

Consumption of black beans and navy beans (Phaseolus vulgaris) reduced azoxymethane-induced colon cancer in rats

Beans (Phaseolus vulgaris) are an important food staple in many traditional diets. There is limited evidence to suggest an inverse relationship between bean consumption and colon cancer. The objective of this study was to determine whether consumption of black beans and/or navy beans would reduce colon carcinogenesis in rats. Rats were fed a modified AIN-93G diet (control) or diets containing 75% black beans or 75% navy beans for 4 wk, and then colon cancer was initiated by administration of two injections of azoxymethane 1 wk apart. At 31 wk after the second injection, the incidence of colon adenocarcinomas was significantly lower (P < 0.05) in rats fed the black bean (9%) and navy bean (14%) diets than in rats fed the control diet (36%). Total tumor multiplicity was also significantly lower in rats fed the black bean (1.1) and navy bean (1.0) diets than in rats fed the control diet (2.2). The 44-75% reduction in colon carcinogenesis in rats fed beans was attributed to 1) more controlled appetites, leading to significantly less body fat, and 2) much greater concentrations of butyrate in the distal colon. It was concluded that eating black beans and navy beans significantly lowered colon cancer incidence and multiplicity.     

Neoplastic pathology in male Sprague-Dawley rats fed AIN-93M diet ad libitum or at restricted intakes

The primary purpose of this study was to evaluate the effects of age and long-term dietary reduction on neoplastic diseases in rats fed the AIN-93M purified diet. Second, pathologic profiles are critical to comprehensive dietary evaluation. Male Sprague-Dawley rats assigned to 2 groups, ad libitum (AL) and dietary restricted (DR), were fed the AIN-93M (casein protein) diet free choice and reduced in amount by 31%, respectively. At 58 weeks of age, the predominant types of lesions in AL and DR rats were pituitary and skin tumors. At 114 weeks of age, the most common lesions were pituitary, adrenal gland, skin, mammary, brain, and pancreatic tumors and mononuclear cell leukemia. However, DR had no significant effect on these lesions. Primary findings demonstrate that DR significantly reduced the total number of tumors per rat and incidence of benign and primary tumors (all organs) but did not reduce the incidence of malignant tumors (all organs). Dietary restriction increased the percentage of unknown deaths. These results may explain why survival rates for AL and DR rats were not significantly different at 114 weeks (43.3 vs 57.5%, respectively). These findings differ from previous studies using NIH-31 cereal diet (Aging Clin Exp Res 2001;13:263; J Nutr 2002;132:101; Aging Clin Exp Res 2003;16(6):68; Aging Clin Exp Res 2004;16:448) where neoplastic lesions rather than nonneoplastic lesions were linked to a significant increase in survival rate among cohorts of DR-fed rats (J Nutr 2002;132:101). Factors such as diet composition and digestibility, although not independent of body weight, may have contributed to differences in rat mortality and may affect humans in a similar manner.     

氟化钠对去卵巢大鼠骨矿盐代谢的影响

用测定骨矿盐含量的方法,分析氟化钠(NaF)对去卵巢大鼠骨矿盐代谢的影响。将健康4月龄雌性SD大鼠24只,用抽签法随机分成4组:正常对照组、假去卵巢组、去卵巢组、去卵巢+NaF组。去卵巢+NaF组大鼠于去卵巢手术后第2 d开始给予NaF溶液灌胃,1 mg/(kg.BW),1次/d,持续11周。结果表明,去卵巢组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重/骨干重(%)均明显低于假去卵巢组(P<0.01);去卵巢+NaF组大鼠骨干重、骨干重/体重、骨灰重、骨灰重/体重、骨灰重/骨干重(%)均较去卵巢组增加(P<0.01)。提示NaF对抗由于去卵巢所引起的骨矿盐含量降低在防治骨质疏松中起重要作用。     

Dietary magnesium supplementation affects bone metabolism and dynamic strength of bone in ovariectomized rats

We evaluated the effect of magnesium supplementation on apparent calcium absorption, bone metabolism and dynamic bone strength in ovariectomized (OVX) rats as a model of postmenopausal women. Two groups of OVX rats were fed a 0.05% Mg diet or a 0.15% Mg diet, and one group of sham-operated rats was fed the 0.05% Mg diet for 42 d. We collected feces and urine of all rats for 3-d periods starting from d 3, 10, 17, 24, 31 and 38 of the feeding experiment for calcium and magnesium balance studies. Urine was collected for 24 h from d 41 of the feeding experiment for measuring deoxypyridinoline. After the 42 d, the rats were killed, serum prepared and femora excised. The apparent calcium absorption in the OVX rats fed 0.15% Mg was significantly lower than both other groups. Additionally, the urinary excretion of deoxypyridinoline (a bone resorption marker) and the serum parathyroid hormone level of the OVX rats fed the 0.15% Mg diet were significantly lower than in the OVX rats fed 0.05% Mg. Serum osteocalcin (a bone formation marker) in the OVX rats fed the 0.15% Mg diet was significantly higher than in the OVX rats fed 0.05% Mg. The breaking force and breaking energy of the femur in the OVX rats fed the 0.15% Mg diet were significantly higher than in the OVX rats fed the 0.05% Mg diet. These results indicate that magnesium supplementation reduces apparent calcium absorption, but promotes bone formation and prevents bone resorption in OVX rats. Moreover, our results indicate magnesium supplementation increases the dynamic strength of bone.     

Daidzein is more efficient than genistein in preventing ovariectomy-induced bone loss in rats

We investigated the ability of genistein and daidzein, two soybean isoflavones, compared with that of 17 alpha-ethinylestradiol, to prevent bone loss in ovariectomized rats, a model for postmenopausal osteoporosis. Female Wistar rats (n = 65; 12 mo old) were either sham-operated (SH; n = 13) or ovariectomized (OVX; n = 52). On d 0, OVX rats were randomly assigned to groups as follows: 13 received genistein [G; 10 mcg/(g body weight. d)], 13 were treated with daidzein [D; 10 mcg/(g body weight. d)], 13 received 17 alpha-ethinylestradiol [E(2); 30 mcg/kg body weight. d)] and 13 were untreated (OVX). Compounds were mixed with a soy protein-free powdered semipurified diet and given orally for 3 mo. On d 90, the bone mineral density (BMD) in lumbar vertebrae, femur and its metaphyseal and diaphyseal zones (rich in cancellous and cortical bone, respectively) was lower in OVX than in SH (P < 0.01). In D or E(2), the four BMD were not different from SH, whereas in G, only the diaphyseal BMD was not different from SH. Image analysis performed in the distal femur metaphysis revealed that the cancellous bone area was lower in OVX than in SH (P < 0.01). Only the area in D was not different from that in SH. Finally, the bone turnover, which was higher in OVX than in SH (P < 0.005 and P < 0.05 for plasma osteocalcin concentration and urinary deoxypyridinoline excretion, respectively), was not different in G, D or E(2) compared with SH. Therefore, consumption of 17 alpha-ethinylestradiol or daidzein was more efficient than genistein in preventing ovariectomy-induced bone loss in rats.     

Hesperidin,a citrus flavonoid,inhibits bone loss and decreases serum and hepatic lipids in ovariectomized mice

The purpose of this study was to examine whether hesperidin inhibits bone loss in ovariectomized mice (OVX), an animal model of postmenopausal osteoporosis. Forty 8-wk-old female ddY mice were assigned to five groups: a sham-operated group fed the control diet (AIN-93G), an OVX group fed the control diet, an OVX+HesA group fed the control diet containing 0.5 g/100 g hesperidin, and an OVX+HesB group fed the control diet containing 0.7 g/100 g alpha-glucosylhesperidin and an OVX+17beta-estradiol (E(2)) group fed the control diet and administered 0.03 micro g E(2)/d with a mini-osmotic pump. After 4 wk, the mice were killed and blood, femoral, uterine and liver were sampled immediately. Hesperidin administration did not affect the uterine weight. In OVX mice, the bone mineral density of the femur was lower than in the sham group (P < 0.05) and this bone loss was significantly prevented by dietary hesperidin or alpha-glucosylhesperidin. The Ca, P and Zn concentrations in the femur were significantly higher in the hesperidin-fed and E(2) groups than in the OVX group. Histomorphometric analyses showed that the trabecular bone volume and trabecular thickness in the femoral distal metaphysis were markedly decreased (P < 0.05) by OVX, and alpha-glucosylhesperidin significantly prevented this bone loss. Furthermore, hesperidin decreased the osteoclast number of the femoral metaphysis in OVX mice, as did E(2). Serum and hepatic lipids were lower in mice that consumed the hesperidin-containing diets (P < 0.05) than in the OVX group fed the control diet. These results suggest a possible role for citrus flavonoids in the prevention of lifestyle-related diseases because of their beneficial effects on bone and lipids.