Effects of high-whey-protein intake and resistance training on renal, bone and metabolic parameters in rats

Consumption of high-protein (HP) diets is postulated to exert a negative influence on bone and renal health. However, no conclusive evidence has been presented related to this issue or to the potential protective action of resistance training on HP-induced systemic effects. We examined the effects of HP diet consumption on food intake, body-weight gain, body composition, and renal, bone and metabolic parameters of rats performing resistance training. A total of ninety-six adult male Wistar rats were randomly distributed in twelve experimental groups (n 8): normal-protein (10%) or HP (45%) diets, with or without resistance training, killed for experimental periods of 1, 2 or 3 months. Diets were based on a commercial whey protein hydrolysate. Consumption of HP diets and resistance training significantly affected food intake, body weight and body composition, as well as the plasma levels of total cholesterol, HDL-cholesterol and TAG. The buffering action of resistance training on such diet-induced alterations was especially evident in the levels of plasma TAG. Consumption of HP diets led to a considerable increase in kidney weight, urinary volume and acidity, as well as in the urinary excretion of Ca, with a parallel reduction in the urinary excretion of citrate (P < 0·05). No apparent deleterious effect on bone mineral content was found. In conclusion, consumption of HP diets caused alterations in renal health status and some metabolic parameters, but did not seem to affect bone status. Resistance training had a protective action against alterations of renal health status and some metabolic parameters such as plasma TAG.     

Consumption of legumes improves certain bone markers in ovariectomized rats

Soybeans are known to protect against osteoporosis, but other legumes frequently consumed in Asia have not been studied to learn if they have a similar protective effect. This study investigated the hypothesis that consumption of soybean, mung bean, cowpea, and adzuki bean has beneficial effects on bone biomarkers in ovariectomized rats. Female Sprague-Dawley rats were either sham operated (sham; n = 7) or surgically ovariectomized and then fed a regular AIN-93M diet (OVX; n = 7) or AIN-93M containing soybean (n = 7), mung bean (n = 7), cowpea (n = 7), or adzuki beans (n = 7) for 10 weeks. No bean consumption significantly altered the body, subcutaneous fat, or uterus weight; however, consumption significantly increased the serum calcium/phosphorous ratio and decreased urinary calcium excretion compared with those of the OVX group. Serum concentration of 17β-estradiol was significantly lower in the OVX group compared with that of the sham group and was lowest in the group fed OVX diet containing soybean. Serum osteocalcin concentration was significantly higher in all OVX rats given a diet with beans compared with the same diet without, but urinary deoxypyridinoline excretion was lowest in the group fed OVX diet containing cowpea. There were no significant differences in bone mineral density or bone mineral content of the right femur, tibia, or lumbar spine or in the trabecular bone volume of the tibia among the diet groups. In conclusion, the consumption of soybean, mung bean, cowpea, and adzuki bean in OVX rats improved osteocalcin, but only those fed cowpea showed decreased bone resorption biomarker, suggesting that cowpea may have the most protective effect on bone in OVX rats.     

Effects of soybean isoflavone dosage and exercise on the serum markers of bone metabolism in ovariectomized rats

This study was designed to determine whether combined treatments with soybean isoflavone dosage and moderate exercise would exhibit synergistically effects on bone metabolism following the onset of menopause. Fifty 12 wk-old female Wistar rats were assigned to five groups: 1) Sham operated (Sham), 2) ovariectomized (OVX), 3) OVX received soybean isoflavone (OVX-IF), 4) OVX exercised (OVX-EXE) and 5) OVX treated with both soybean isoflavone and exercise (OVX-IF-EXE). All rats were fed a normal diet ad libitum. Daily soybean isoflavone dosage was 50 mg/kg body weight. The vehicle was given in Sham, OVX and OVX-EXE groups. The drugs were all oral administered using a stomach tube. Exercising rats were trained on an uphill treadmill at 20 m/min for 1h/day, 5 days/week. The experimental duration consisted of the adaptation periods of 2 weeks and treatment periods of 8 weeks. The results showed that the uterus relative weights in OVX-EXE, OVX-IF and OVX-IF-EXE groups were all lower than those in Sham, they were higher than those in the OVX group. Serum alkaline phosphates (AKP) activities of OVX was significantly increased as compared to that of Sham (p<0.01). OVX-IF and OVX-IF-EXE respectively decreased the Serum alkaline phosphates activities, as compared to that of OVX (p<0.01). The tartrate-resistant acid phosphatase (TRAP) value of OVX was significantly increased as compared to that of Sham (p<0.05). OVX-IF decreased the TRAP as compared to that of OVX (p<0.05). These results suggest soybean isoflavone and resistance exercise both can restrain ovx-induced bone loss. But their mechanisms may be different.     

Effects of tuna bone and herbal extract on bone metabolism in ovariectomized rats

This study was conducted to examine the effects of herb extract addition on bone metabolism of ovariectomized (OVX) rats fed a diet with tuna bone as a source of calcium. The experimental groups were sham–control (CaCO₃ [CC]), OVX-CC (OVX-control), OVX–CC + herb extract, OVX–tuna bone powder (TB), OVX–tuna bone powder + herb extract, OVX–citrated tuna bone powder (CTB), and OVX–citrated tuna bone powder + herb extract (CTBH). The herb extract included Rehmanniae radix and Angelicae gigantis radix, following the prescribed theories of Oriental herb medicine. In the OVX-CTBH group, the level of fecal (33.6%) and urinary calcium excretion (45.8%) greatly decreased compared with the TB groups. Osteocalcin concentrations were significantly lower in the OVX-CC group and higher in the OVX-CTB group. The deoxypyridinoline value was significantly influenced by ovariectomy. It was elevated in all OVX groups compared with the sham group, and it was reduced by 12.8% in rats supplemented with the herb extract. The bone density value per 100-g body weight was lowest in the TB group, and it was higher in the tuna bone powder + herb extract, CTB, and CTBH groups. We concluded that TB can be a good calcium source, and it was effective in maintaining skeletal metabolism of OVX rats when it was fed in the form of citrated or herb extract–supplemented diets.     

玛咖独行菜对卵巢切除术后大鼠血脂及骨质代谢的影响

目的利用雌激素低下动物模型,探讨玛咖独行菜(LepidiummeyemiiWalp,俗称Maca)对雌性大鼠体脂、性激素、骨代谢的影响。方法健康SD雌性大鼠进行卵巢切除术后根据体重随机分为模型组、雌激素组以及Maca低、中、高剂量组;另设未做卵巢切除术的假手术组作为对照组。雌激素组每天灌胃己烯雌酚(30μg/kgbw);Maca低、中、高剂量组每天分别灌胃Maca悬浊液0.3、0.6、1.8g/kg;假手术组和模型组每天灌胃蒸馏水。7周后测定各组大鼠体重、子宫和肾上腺重量,及血脂、性激素、骨代谢相关指标的水平。结果模型组显示卵巢切除术后大鼠体重快速增长,子宫、肾上腺重量降低,雌、孕激素及睾酮水平下降,血脂水平增高,血碱性磷酸酶水平升高(和假手术组相比,P<0.05)。相比之下,给予己烯雌酚的雌激素组血雌激素水平提高、子宫重量维持不变、体重过度增长得到改善(和模型组相比,P<0.05);Maca高剂量组大鼠的低密度脂蛋白胆固醇、甘油三酯和血碱性磷酸酶水平明显降低,骨钙素的作用增强(和模型组相比,P<0.05),但性激素分泌无显著变化。结论玛咖独行菜有助于改善卵巢切除术后血脂异常和骨质代谢。     

大豆异黄酮对去卵巢大鼠骨力学性能的影响

目的　探讨植物雌激素大豆异黄酮对大鼠去侧巢后骨密度和骨力学指标变化的影响。方法　腹腔手术切除大鼠双侧卵巢 ,分为去卵巢对照组、大豆异黄酮剂量组和雌激素对照组 ,并设假手术对照组。喂养 16周后 ,分离股骨 ,双能量X射线骨密度仪测定骨密度 (BMD) ,三点弯曲实验法测定骨力学指标弯曲强度 (Flexuralstrengh)和弯曲弹性模量 (Flexuralelasticmodule) ,分析天平称量骨的重量。结果　大鼠去卵巢后骨密度显著下降 ,股骨的力学性能指标有较大变化。给予大豆异黄酮和雌激素后 ,可使骨密度显著提高 (P <0 0 1) ,存在一定的剂量 -效应关系 ,弯曲强度和弯曲弹性模量明显增加。雌激素组 (EC)大鼠的股骨长度和不同状态下的骨重量显著降低 ,其它各组之间经统计学分析无显著性变化。结论　大豆异黄酮和雌激素可增加去卵巢大鼠股骨骨密度、改善骨的生物力学性能     

大豆异黄酮对去势大鼠骨代谢的影响

[目的]探讨大豆异黄酮改善激素缺乏大鼠骨营养状况及作用机制。[方法]选用卵巢切除大鼠所诱发的骨质疏松模型,给予大豆异黄酮治疗,同时设假手术组及模型对照组。3个月后测定大鼠骨密度、骨钙含量及骨代谢酶学指标。[结果]大豆异黄酮可提高去势大鼠的骨密度、骨钙含量;降低血清碱性磷酸酶(AKP)及抗酒石酸酸性磷酸酶(TRACP)的活性(P<0.05),其作用与剂量有关。[结论]大豆异黄酮能够增加去势大鼠的骨密度,有类似雌激素样作用,可有效防治卵巢切除大鼠的骨量丢失,其作用机制可能是通过降低骨转换率来实现。     

Effects of usual nutrient intake and vitamin D status on markers of bone turnover in Swiss adolescents

OBJECTIVE: To evaluate the effects of nutrient intake and vitamin D status on markers of type I collagen formation and degradation in adolescent boys and girls. DESIGN: Cross-sectional study. SETTING: Canton of Vaud, West Switzerland. SUBJECTS: A total of 92 boys and 104 girls, aged 11-16 y. Data were collected on height, weight, pubertal status (self-assessment of Tanner stage), nutrient intake (3-day dietary record) and fasting serum concentration of 25-hydroxyvitamin D (25OHD), and markers of collagen formation (P1NP) and degradation (serum C-terminal telopeptides: S-CTX). RESULTS: Tanner stage was a significant determinant of P1NP in boys and girls and S-CTX in girls. Of the nutrients examined, only the ratio of calcium to phosphorus (Ca/P) was positively associated with P1NP in boys, after adjustment for pubertal status. 25OHD decreased significantly at each Tanner stage in boys. Overall, 15% of boys and 17% of girls were identified as being vitamin D insufficient (serum 25OHD <30 nmol/l), with the highest proportion of insufficiency at Tanner stage 4-5 (29%) in boys and at Tanner stage 3 (24%) in girls. A significant association was not found between 25OHD and either bone turnover marker, nor was 25OHD insufficiency associated with higher concentrations of the bone turnover markers. CONCLUSIONS: The marked effects of puberty on bone metabolism may have obscured any possible effects of diet and vitamin D status on markers of bone metabolism. The mechanistic basis for the positive association between dietary Ca/P ratio and P1NP in boys is not clear and may be attributable to a higher Ca intake per se, a critical balance between Ca and P intake or higher dairy product consumption. A higher incidence of vitamin D insufficiency in older adolescents may reflect a more sedentary lifestyle or increased utilisation of 25OHD, and suggests that further research is needed to define their requirements. SPONSORSHIP: Nestec Ltd and The Swiss Foundation for Research in Osteoporosis.     

山茶籽联合雌二醇对去卵巢大鼠骨重建和骨代谢酶的影响

目的:了解山茶籽联合雌二醇对去卵巢大鼠骨重建和骨代谢酶的影响,为山茶籽联合雌二醇治疗Ⅰ型骨质疏松症提供实验依据。方法:将90只5月龄健康雌性大白鼠分成假手术组(sham)、去卵巢模型组(OVX)、山茶籽组、雌二醇组(E2)、小剂量山茶籽+雌二醇组(Ts+E2),每组各18只。各实验组在第8、12、16周,随机处死6只大鼠,取左股骨切片观察骨组织,取右股骨测量骨密度,取左心血测量血清雌二醇、碱性磷酸酶。数据进行统计学分析。结果:OVX组的血清雌二醇和骨密度明显低于sham组(P<0.01),而血清碱性磷酸酶明显高于sham组(P<0.01);3个治疗组与sham组相比,各时间的血清雌二醇、碱性磷酸酶、骨密度均无显著性差异(P>0.05)。结论:小剂量的雌二醇联合山茶籽对去卵巢大鼠的骨质疏松症的治疗效果与单独使用较大剂量的山茶籽或较大剂量的雌二醇的治疗效果相近。     

大豆异黄酮对去卵巢大鼠血脂及骨生化指标的影响研究

探讨大豆异黄酮对去卵巢大鼠血清中血脂指标、骨代谢生化指标及激素水平的影响。选择 4月龄的Wistar大鼠 ,根据体重随机分为 6组。除 1组行单纯开腹手术外 ,其它 5组均切除双侧卵巢 ,分别为 :去卵巢对照组 ;高剂量大豆异黄酮组 ;中剂量大豆异黄酮组和低剂量大豆异黄酮组 ;雌激素组。喂养 16周后 ,处死大鼠 ,分离血清进行分析指标的测定。结果发现 :给予去卵巢大鼠大豆异黄酮后 ,血清中高密度脂蛋白(HDL)含量与去卵巢对照组相比有所增高 (P <0 0 5 ) ;总胆固醇 (TC)、甘油三酯 (TG)指标下降 ;骨吸收指标显著降低 ,骨形成指标骨钙素水平与去卵巢组比有所提高 ;同时 ,大鼠切除卵巢后 ,体内雌激素水平显著下降。结果显示 :大豆异黄酮对去卵巢大鼠的血脂有一定的调节作用 ,对骨吸收有显著的抑制作用     

葛根异黄酮对去卵巢大鼠骨骼质量的影响

目的:观察葛根异黄酮(TIP)对去卵巢大鼠骨骼质量的影响。方法:选用健康成年SD雌性大鼠40只,随机分为5组:假手术组、模型对照组、低、中、高剂量TIP组;假手术组切除卵巢旁脂肪组织,其余各组均切除双侧卵巢,建立去卵巢大鼠动物模型。按25、50、100 mg/kg 3个剂量的TIP分别给去卵巢大鼠灌胃3个月,实验结束后处死大鼠,用相关方法检测骨骼质量变化的指标。结果:中、高剂量TIP组动物的体重与相对应时相的模型组比较均有下降(P<0.05);中、高剂量TIP组大鼠股骨重量、骨钙含量与模型对照组比较增加(P<0.05);高剂量TIP组大鼠的血清钙含量增高,血清磷、骨钙素和碱性磷酸酶含量均低于模型对照组(P<0.05);中、高剂量TIP组大鼠的股中心BMD和远心BMD均随葛根异黄酮剂量的增加而增加,呈剂量—效应关系,与模型对照组比较差异均有显著性(P<0.05)。结论:一定剂量葛根异黄酮能提高骨钙含量、增加骨密度,对去卵巢大鼠骨骼质量有明显的改善作用。     

大豆异黄酮对去卵巢大鼠骨钙、骨强度的影响

目的　利用卵巢切除大鼠模型 ,研究大豆异黄酮对体内骨转换、雌二醇、骨钙含量及骨强度的影响 ,探讨大豆异黄酮的剂量 效应关系。方法　卵巢切除大鼠分为 3个剂量组 ,分别灌胃给与 12 . 6 5 (L SI,低剂量组 ) ,2 5 . 30(M SI ,中剂量组 ) ,37. 95mg/(kg·bw) (H SI ,高剂量组 )。同时设阴性对照组 (OVX)和假手术组 (Sham) ,以蒸馏水灌胃。喂养 12周后 ,处死大鼠 ,分离血清 ,同时剥离右侧股骨及右侧胫骨 ,进行各项指标的测定。结果　OVX组骨形成指标碱性磷酸酶 (AKP)比Sham组及H SI组显著升高 (P <0. 0 5 ) ,其骨吸收指标抗酒石酸酸性磷酸酶 (StrACP)显著性高于Sham组、M SI组及H SI组 (P <0 . 0 5 )。Sham组及各大豆异黄酮剂量组雌二醇 (E2 )有上升趋势 ,中剂量组(M SI)E2 有显著性上升 (P <0 . 0 5 )。Sham组与大豆异黄酮各剂量组内钙含量与OVX组相比显著增高 ,反映骨强度性能的指标 (最大负载、弹性系数及能量 )也较OVX组明显增强。结论　大豆异黄酮能显著改善但不能完全逆转业已形成的骨质疏松。     

Vitamin K, bone turnover, and bone mass in girls

BACKGROUND: Vitamin K has been suggested to have a role in bone metabolism, and low vitamin K intake has been related to low bone density and increased risk of osteoporotic fracture. OBJECTIVE: The objective of this study was to determine whether phylloquinone (vitamin K(1)) intake and biochemical indicators of vitamin K status are related to bone mineral content (BMC) and markers of bone formation and bone resorption in girls. DESIGN: Vitamin K status [plasma phylloquinone concentration and percentage of undercarboxylated osteocalcin (%ucOC)] was measured at baseline in a study of 245 healthy girls aged 3-16 y. Cross-linked N-telopeptide of type 1 collagen (NTx) breakdown, osteocalcin, and bone-specific alkaline phosphatase were measured to reflect bone resorption and formation. BMC of the total body, lumbar spine, and hip and dietary phylloquinone intake were measured annually for 4 y. RESULTS: Phylloquinone intake (median: 45 microg/d) was not consistently associated with bone turnover markers or BMC. Better vitamin K status (high plasma phylloquinone and low %ucOC) was associated with lower bone resorption and formation. Plasma phylloquinone was inversely associated with NTx and osteocalcin concentrations (P < 0.05), and %ucOC was positively associated with NTx and bone-specific alkaline phosphatase concentrations (P < 0.05). Indicators of vitamin K status were not consistently associated with current BMC or gain in BMC over the 4-y study period. CONCLUSIONS: Better vitamin K status was associated with decreased bone turnover in healthy girls consuming a typical US diet. Randomized phylloquinone supplementation trials are needed to further understand the potential benefits of phylloquinone on bone acquisition in growing children.     

Effect of Korean oriental medicine extract on bone mass as compared with alendronate in ovariectomized rats

A number of alternative medicines (AMs) have often been used as traditional therapies for various diseases without scientific or clinical evidence supporting their use. The present study examined the pharmaceutical effects of an AM extract with a long history of use as a traditional medicine for various bone diseases. To evaluate it as a potential candidate for use as an anti-osteoporotic drug, we investigated the effects of the AM extract on the progression of bone loss in ovariectomized (OVX) rats fed a calcium (Ca)-deficient diet for 4 or 12 weeks. We also compared the AM extract with alendronate, an anti-resorptive drug. The AM extract did not influence bone turnover as indicated by biochemical markers [i.e., deoxypyridinoline (DPD)]. In contrast, alendronate treatment seemed to reduce bone turnover via inhibition of bone resorption as evidenced by reduced urinary DPD concentrations accompanied by a tendency for decreased serum tartrate-resistant acid phosphatase. Administration of alendronate or AM extracts did not significantly affect bone density, although both tended to increase bone mineral density (BMD) and bone strength of the femur. Although both treatments did not affect vertebral BMD and bone strength, histological analysis of vertebrae showed well-developed trabecular networking in OVX rats treated with alendronate or AM extract, in contrast to the thin and disconnected trabecule in OVX rats. In conclusion, the AM extract produced a very weak effect on the prevention of bone loss induced by OVX and Ca deficiency in rats, but was similar to the results observed with alendronate. Further verification is necessary to justify the use of the AM extract as a treatment for osteoporosis.     

Effects of a fermented vegetable product on fat deposition and bone metabolism in ovariectomized rats

We examined the effects of a fermented vegetable product (FVP), fermented by yeast as well as lactic acid bacteria, on body weight and fat deposition after ovariectomy in 10-wk-old Sprague-Dawley rats. The rats were divided into the following 5 groups: (1) ovari-ectomized rats fed as usual (OVX); (2) ones receiving FVP at a daily dose of 100 mg/kg (LOW); (3) ones receiving FVP at a daily dose of 1000 mg/kg (HIGH); (4) ones receiving a calcium-free diet (Ca-FREE); (5) sham-operated rats (SHAM). A slight increase in body weight was observed in the LOW group compared with the OVA group. The rate of increase in total fat content was lowest in the LOW group, but both bone weight and strength were similar to those in the other ovariectomized groups. In conclusion, the low dose of FVP turned out to reduce fat content without affecting bone weight and strength.     

Effects of soy isoflavone and/or estrogen treatments on bone metabolism in ovariectomized rats

This study investigated whether soy isoflavone intake, with or without estrogen treatment, can reduce postmenopausal bone loss, and whether soy isoflavones can be an alternative for estrogen replacement therapy using a postmenopausal osteoporotic rat model in which ovariectomized female rats were fed a low calcium, high fat diet. Nine-week-old female Sprague-Dawley rats were ovariectomized and then fed low (0.1%) calcium diets with or without soy isoflavone supplementation (80 or 160 ppm) for 6 weeks. Some ovariectomized rats were fed the same diets but also injected with estrogen (10 microg/kg of body weight) subcutaneously. Serum calcium and phosphate levels were normal in all rats. Serum alkaline phosphatase activities were not affected by the treatments. Serum tartrate-resistant acid phosphatase activities and urinary hydroxyproline levels were not different between experimental groups. Bone mineral (calcium and phosphorus) contents were increased in the rats supplemented with 80 ppm soy isoflavone or the rats treated with only estrogen without soy isoflavone. Therefore, the effect of 80 ppm soy isoflavone supplementation was the same as estrogen injection, but there was no beneficial effect from combining soy isoflavones and estrogen injections. When 160 ppm soy isoflavone was used, the benefits were lessened or disappeared altogether. These results suggest that appropriate soy isoflavone supplementation prevents postmenopausal bone loss without estrogen injection and may have efficacy as an alternative to estrogen therapy.     

膳食钙、骨密度与儿童肥胖相关代谢异常的关系

越来越多研究支持增加钙摄人可减少代谢综合征的发生率,儿童时期的牛奶摄入水平及保持饮用牛奶的习惯与成年后骨密度呈正相关,有助于获得更高的骨峰值。本文总结了膳食钙摄入量对骨密度和儿童肥胖相关代谢异常之间的关系。     

染料木黄酮对去势大鼠骨密度、生物力学和形态学参数的影响

目的　研究染料木黄酮对去势大鼠骨密度、生物力学和形态学参数的影响。方法　将 4 7只雌性Wistar大鼠随机分为假手术组、去势对照组、去势 +雌激素组 (己烯雌酚每天 2 0 μg kgBW)、去势 +染料木黄酮组 (剂量分别为每天 2 5、5 0、1 0 0mg kgBW )。饲养 3个月后处死 ,测定骨密度、生物力学参数和形态学参数。结果　去势后大鼠骨小梁体积减少 ,平均骨小梁板密度降低 ,平均骨小梁板间隙增加 ,股骨骨密度降低 ,与假手术组相比均有显著性差异 (P <0 0 5 ) ,但最大应力只有降低的趋势。补充染料木黄酮后 ,骨小梁体积增加 ,平均骨小梁板厚度和密度增大 ;股骨骨密度和最大应力有改善的趋势。结论　染料木黄酮可以减少去势大鼠骨量的丢失 ,预防骨质疏松的发生     

Effects of high magnesium intake on bone mineral status and lipid metabolism in rats

Effects of magnesium (Mg)-intake on mineral levels in bone, blood and various tissues, bone density and plasma lipids were examined in 4-wk-old, female Wistar rats fed diets of five different Mg-contents of 1/10, 1 (standard diet (Mg 47 mg/100 g diet): control group), 2, 5 and 10-fold of the standard content for 4 wk. In rats fed the 1/10-fold Mg diet, the body weight gain declined with a statistical significance compared to control rats, while no significant differences were observed in rats fed on the 2-, 5-, and 10-fold Mg diets. The imbalance of mineral concentrations in the rats fed 1/10 Mg diet was induced, but in the rats fed high Mg diets were not induced except in tibia. Mg concentration in tibia of rats fed the 10-fold Mg diet significantly increased compared to the control group. All groups (1/10-fold, 2-, 5-, and 10-fold Mg groups) showed no significant changes in tibial mineral levels, except Mg in the 10-fold group, compared to the control group. With increase in Mg-intake, decline of plasma lipid parameters such as cholesterol, triglycerides and phospholipids are induced. Based on these results, it was suggested that a higher Mg-intake (around 5-fold of the standard Mg-content) might have a prophylactic potential against the onset of hyperlipidemia and cardiovascular disease by reducing lipid indices, and Mg decline in bone.