雌激素加间断孕激素对去卵巢大鼠绝经后骨质疏松模型子宫及骨组织形态计量学的影响

目的观察雌激素（E）加间断孕激素（P）对双侧卵巢切除（OVX）大鼠骨组织形态计量学的影响.方法35只雌性大鼠随机分成5组,每组7只.①假手术（Sham）组、②卵巢切除（OVX）组、③卵巢切除加雌激素（OVX＋E）组、④卵巢切除加孕激素（OVX＋P）组、⑤卵巢切除加雌激素和孕激素（OVX＋E＋P）组.实验10 w后处死大鼠,称取大鼠子宫和股骨湿重,并测定子宫内膜厚度、骨密度,并对第4、5腰椎进行骨组织形态计量学分析.结果与Sham组相比：OVX组和OVX＋P组体重和骨组织形态计量学参数Tb.Sp和MAR增加,子宫重量、股骨重量和BMD减少,子宫内膜变薄,骨组织形态计量学参数BV/TV和Tb.Th减少（P＜O.05）;而OVX＋E＋P组股骨重量、BMD、子宫重量、子宫内膜厚度和骨组织形态计量学参数BV/TV、Tb.Th、Tb.Sp和MAR均无明显差异（P＞0.05）.OVX＋E组子宫重量明显增加、子宫内膜明显增厚（P＜O.05）.结论单用孕激素不能阻止OVX导致的骨丢失;单用雌激素导致OVX鼠子宫重量增加和子宫内膜增厚;雌激素加间断孕激素能阻止OVX导致的骨丢失和体重增加,并可避免OVX和雌激素对子宫内膜的不良作用;孕激素的间断加入不影响雌激素对OVX大鼠骨代谢的有利作用.     

雌激素加间断孕激素对去卵巢大鼠模型骨转换生化指标的影响

目的观察雌激素(E)加间断孕激素(P)对双侧卵巢切除(OVX)大鼠模型骨转换生化指标的影响。方法35只雌性大鼠随机分成5组,每组7只。①假手术(Sham)组、②卵巢切除(OVX)组、③卵巢切除 雌激素(OVX E)组、④卵巢切除 孕激素(OVX P)组、⑤卵巢切除 雌激素 孕激素(OVX E P)组。实验10w后处死大鼠,测定股骨重量、骨密度(BMD),检测血清骨钙素(BGP)、碱性磷酸酶(ALP)、钙、磷,同时检测尿钙、羟脯氨酸(HOP)及肌酐(Cr)等指标。结果与Sham组相比:OVX组和OVX P组体重增加、股骨重量和BMD减少(P<0.05),血清BGP、ALP及尿钙、HOP及Cr升高,而OVX E组、OVX E P组股骨重量和BMD、血清BGP、ALP及尿钙、HOP及Cr均无明显差异(P>0.05)。结论单用孕激素不能阻止OVX导致的骨吸收及骨量丢失;雌激素 间断孕激素能阻止OVX导致的骨吸收及骨量丢失;孕激素的间断加入没有影响雌激素对OVX大鼠骨代谢的有利作用。     

上坡运动对去卵巢骨质疏松大鼠股骨及椎体骨密度的影响

目的探讨上坡运动对去卵巢骨质疏松大鼠骨密度(BMD)的影响。方法将48只3月龄雌性SD大鼠按体重随机分成对照组、造模组、雌激素组和运动组,每组12只,对照组仅切除卵巢附近一团脂肪,其余各组均切除双侧卵巢。术后按不同要求灌胃给药和运动,干预16 w后处死大鼠,观察各组大鼠左侧股骨及第3腰椎椎体BMD的变化。结果与造模组比较,雌激素组和运动组第3腰椎椎体和股骨BMD均显著升高(P0.05)。结论切除卵巢可致大鼠骨质疏松。上坡运动可有效提高椎骨和股骨BMD,减缓骨量的降低速度,防治骨质疏松。     

中等强度跑台运动对去卵巢大鼠骨量和相关血清性激素水平的影响

目的 观察中等强度跑台运动对去卵巢大鼠骨量和相关血清性激素水平的影响,探讨其预防绝经后骨质疏松发生的作用机制.方法 40只未经产雌性SD大鼠,按体重随机分为假手术、去卵巢静止、去卵巢运动和雌激素4组.去卵巢运动组每周进行4次45 min、速度18 m/min,坡度5°的跑台训练;雌激素组每周颈部皮下注射3次17β-雌二醇,每次50 μg/kg体重.结束后,称量腹腔内脂肪和子宫重量;测定血清雌激素(E_2)、孕酮(P_4) 和睾酮(T)含量;检测右侧游离股骨和胫骨的骨密度(BMD)和骨矿物(BMC) 含量.结果 中等强度跑台运动能显著增加去卵巢大鼠股骨近端、中段和远端以及胫骨近端的BMC、BMD以及血清E_2水平,显著降低去卵巢大鼠腹腔内脂肪重量以及血清P4和T水平.结论 中等强度跑台运动抗去卵巢大鼠骨量下降的效应至少部分可能与其对血清性激素水平的调节有关.     

双能X线吸收法测定大鼠骨量的评价及去卵巢骨丢失敏？…

目的　探讨双能X线吸收法 (DXA)测量大鼠骨密度 (BMD)的精密度和准确度及大鼠去卵巢后骨丢失的敏感区域。方法　用扇形束DXA(QDR45 0 0A)重复测量 16只SD大鼠不同骨胳区域BMD的变异系数 (CV)评价精密度 ;测量 40只大鼠骨矿含量 (BMC)与骨灰重比较评价准确度 ;与假手术组比较测定大鼠去卵巢后不同骨胳区域骨丢失率的变化选择骨丢失敏感区域。结果DXA测量BMD的CV为全身 (0 .71± 0 .44 ) % ,腰椎 (0 .82± 0 .5 3) % ,股骨 (0 .5 2± 0 .2 7) % ,胫骨(0 .81± 0 .11) % ,股骨和胫骨的各亚区 (1.46± 0 .2 6 ) % ;BMC与骨灰重呈高度正相关 (r =0 .984～0 .85 5 ) ,BMC显著低于骨灰重 (P <0 .0 0 1) ;生长期大鼠去卵巢 14周与假手术组BMD比较 ,腰椎(- 7.0 3% )、股骨远端 (- 9.0 3% )和近端 (- 7.49% )及胫骨近端 (- 11.7% )BMD显著减少 ,胫骨远端BMD显著增加 (8.82 % )。结论　DXA测量大鼠骨量是精密和有效的方法 ,胫骨近端干骺端和股骨远端干骺端是大鼠去卵巢后骨丢失最敏感区域。     

尼尔雌醇皮埋剂保护去卵巢大鼠的骨量

目的：探讨尼尔雌醇（NYL）皮埋剂对卵巢切除（OVX）大鼠骨量的影响。为长期雌激素替代治疗提供一种新的选择。方法：用DEXA分别测定假手术（Sham）组、卵巢切除（OVX）组、卵巢切除加左炔诺孕酮皮埋剂（LNG）组、卵巢切除加LNG皮埋剂和NYL皮埋剂（LNG＋NYL）组及OVX加NYL皮埋剂（NYL）组大鼠的活体和离体骨密度（BMD），并对血清碱性磷酸酶（ALP）和尿吡啶啉／肌酐（Pyr/Cr)进行检测。结果：与Shasm组比较，OVX组和LNG组大鼠全身，腰椎活性BMD和腰椎，股骨整体及各兴趣区（除第3兴趣区）、胫骨整体及干骺端第1兴趣区离体BMD均显著下降（P＜0．05－P＜0．01），而血清ALP和尿Pyr/Cr增高，后者差异有显著性（P＜0．05）。LNG＋NYL皮埋剂组和NYL皮埋剂组BMD较OVX组增加，在许多部位差异有显著性（P＜0．05－P＜0．01），BMD与Sham组接近，而它们的血清ALP和尿Pyr/Cr较OVX组下降（P＜0．05－P＜0．01）。结论：LNG皮埋剂不能阻止OVX导致的骨丢失，NYL皮埋剂有保护OVX大鼠骨量的作用。     

己烯雌酚对去卵巢大鼠不同部位骨骼的影响

目的　观察己烯雌酚对去卵巢大鼠不同部位骨骼的影响。方法　己烯雌酚SD大鼠行双侧卵巢去除术后 ,灌喂DES 2 2 5μg/ (kg·d) ,持续 90d。用骨组织形态计量学等方法测量胫骨上段和腰椎松质骨及胫骨中段皮质骨的动态参数和静态参数 ,同时测量血清生化指标及子宫内膜厚度。结果　己烯雌酚可使去卵巢大鼠胫骨上段 (PTM)和腰椎 (LV)松质骨的骨量增加、骨小梁分离度减少 ,骨形成和骨吸收降低。与去卵巢组比较 ,DES组的PTM骨量增加 1 54 8% ,LV骨量增加 2 0 3 % ,胫骨中段 (Tx)皮质骨的变化不明显。己烯雌酚还降低去卵巢大鼠血清总胆固醇含量 ,但增加子宫内膜厚度。结论　己烯雌酚能有效预防去卵巢大鼠的骨丢失 ,但是对不同部位的骨骼的作用不同 ,而且具有刺激子宫的作用。     

人甲状旁腺激素相关蛋白片段对骨质疏松大鼠股骨和腰椎骨密度的影响

目的观察人甲状旁腺激素相关蛋白（PTHrP1-34）对去卵巢的骨质疏松大鼠股骨、腰椎骨密度（BMD）的影响。方法80只4月龄Wistar健康雌性大鼠。其中60只行双侧卵巢摘除术，20只做假手术，6w后各处死10只证实骨质疏松造模成功。剩余50只骨质疏松模型鼠随机分为5个治疗组，每组10只，其他10只假手术组作对照。PTHrP治疗组（PTHrP20组，PTHrP40组，PTHrP80组）分别用20、40、80μg／kg剂量，每日皮下注射1次PTHrP1-04；雌二醇治疗组（E2组）用苯甲酸雌二醇40μg/kg，每3天注射1次；安慰荆组及假手术对照组分别用生理盐水，每3d注射1次。治疗3个月后，测定并比较股骨、腰椎不同部位BMD及血清钙、磷、碱性磷酸酶（ALP）水平。结果双侧卵巢摘除6W后，大鼠腰椎BMD明显低于假手术组（P〈0．05）。3个月治疗后，PTHrP40组和PTHrP80组大鼠股骨、腰椎BMD明显高于安慰剂组，与E2组无显著差异，腰椎BMD较PTHrP20组明显升商（P〈0．05）；PTHrP40组与PTHrP80组无明显差异。结论每日每公斤体重皮下注射40和80μg PTHrP1-34对左卵巢骨质疏松大鼠股骨、腰椎BMD均有增高作用。对腰椎作用更为明显。     

雷洛昔芬对去卵巢大鼠骨组织雌激素受体α表达水平的调节

目的探讨雷洛昔分对雌激素受体α(ER-α)mRNA基因表达的调节作用及其与骨密度(BMD)之间的关系。方法将50只3.5月龄雌性Wistar大鼠分为5组,每组10只。分别为假手术组(S组);双侧卵巢切除(OVX)组(O组);双侧卵巢切除+雌激素治疗组(E组);双侧卵巢切除+雷洛昔芬低剂量组(1.0mg/100g体质量RL组);双侧卵巢切除+雷洛昔芬高剂量组(10mg/100g体质量RH组)。采用灌胃给药。12周后处死动物,提取胫骨骨组织总RNA,以β-actin为内参,RT-PCR扩增检测OVX大鼠ER-α mRNA表达水平,并用双能X线骨密度仪(DEXA)测定股骨BMD。结果手术后12周与O组比较,E组、RL组股骨BMD升高,差异有统计学意义(均P0.01),与S组比较,O组、RH组股骨BMD降低,差异有统计学意义(均P0.01)。S组、E组和RL组大鼠骨组织ER-αmRNA表达水平较O组明显增高(P0.01),术后S组、E组和RL组表达水平差异无统计学意义(P0.05)。结论雷洛昔芬可能通过上调ER-α mRNA基因表达抑制破骨细胞骨吸收,减少骨量丢失。     

中等强度跑台运动对去卵巢大鼠后肢骨骨量和脂质含量的影响

目的 观察中等强度跑台运动对去卵巢大鼠后肢骨骨量及脂质含量的影响.方法 40只雌性3月龄SD大鼠按体重随机分为假手术组、去卵巢静止组、去卵巢运动组和雌激素组,每组10只.实验结束时,双能X线骨密度仪检测游离股骨和胫骨的骨密度(BMD)和骨矿物含量(BMC),乙醇/氯仿提取股骨远端及胫骨近端总胆固醇(TC)和甘油三酯(TG).结果 (1)与假手术组相比,去卵巢静止组大鼠股骨远端(P＜0.05)及胫骨近端(P ＜0.01)BMD和BMC显著下降,而股骨远端Tc(P＜0.05)、TG(P ＜0.01)和胫骨近端TG(P＜0.01)显著升高;(2)与去卵巢静止组相比,去卵巢运动组和雌激素组股骨远端及胫骨近端BMD和BMC显著升高(P＜0.05),去卵巢运动组大鼠股骨远端TG(P ＜0.01)、雌激素组大鼠股骨远端TC(P＜0.05)、TG(P＜0.01)和胫骨近端TG(P＜0.o1)显著降低.结论 中等强度跑台运动能显著抑制去卵巢大鼠后肢骨骨量的减少和脂质含量的增加.     

Lasofoxifene (CP-336,156), a novel selective estrogen receptor modulator,in preclinical studies

Estrogen replacement therapy is reported to reduce the incidence of vertebral fractures in postmenopausal women, however, its compliance is limited because of side effects and safety concerns. Estrogen’s side effects on breast and uterine tissues leading to the potential increased risk of uterine and breast cancer limit widespread estrogen usage. Thus, there is a significant medical need for a therapy that protects against postmenopausal bone loss but is free of estrogen’s negative effects on reproductive tissues. Selective estrogen receptor modulators (SERMs) have been investigated as an alternative to hormone replacement therapy. One such compound, raloxifene, has been approved for the prevention and treatment of osteoporosis. Lasofoxifene (LAS), a new, nonsteroidal, and potent SERM, is an estrogen antagonist or agonist depending on the target tissue. LAS selectively binds with high affinity to human estrogen receptors. In ovariectomized (OVX) rat studies, LAS prevented the decrease in femoral bone mineral density, tibial and lumbar vertebral trabecular bone mass at an ED₁₀₀ of about 60 μg/kg/day. LAS inhibited the activation of trabecular and endocortical bone resorption and bone turnover in tibial metaphyses and diaphyses, and lumbar vertebral body in OVX rats. In addition, LAS decreased total serum cholesterol, inhibited body weight gain and increased soleus muscle weight in OVX rats. Similarly, LAS prevented bone loss induced by orchidectomy or aging in male rats by decreasing bone resorption and bone turnover while it had no effect in the prostate. Further, LAS decreased total serum cholesterol in intact aged male rats or in orchidectomized male rats. Synergestic skeletal effects were found with LAS in combination with bone anabolic agents such as prostaglandin E₂ (PGE₂), parathyroid hormone (PTH) or a growth hormone secretagoue (GHS) in OVX rats. In combination with estrogen, LAS inhibited the uterine stimulating effects of estrogen but did not block the bone protective effects of estrogen. In immature and aged female rats, LAS did not affect the uterine weight and uterine histology. In OVX adult female rats, LAS slightly but significantly increased uterine weight. These results demonstrated that LAS produced effects on the skeleton indistinguishable from estrogen in female and male rats. However, unlike estrogen, LAS had little effect on uterine weight and cellular proliferation of uterus in female rats. In preclinical anti-tumor studies, LAS inhibited human breast cancer growth in mice bearing MCF7 tumors, prevented NMU-induced mammary carcinomas and possessed chemotherapeutic effects in NMU-induced carcinomas in rats. Therefore, we conclude that LAS possesses the antiestrogenic effects in breast tissue and estrogenic effects in bone and serum cholesterol, but lacks estrogen’s side effects on uterine tissue. These data support the therapeutic potential of LAS for the prevention and treatment of postmenopausal bone loss and mammary carcinomas in humans.     

Dose-dependent effects of tamoxifen on long bones in growing rats: influence of ovarian status

Tamoxifen is a nonsteroidal antiestrogen which has been reported by various investigators to have estrogen agonist and antagonist effects on rat bone. These different interpretations may be due to differences in the ovarian status, estrogen levels, and/or tamoxifen levels of the rats. To address this issue, a dose response was determined for the effects of tamoxifen on bone histomorphometry in intact female and ovariectomized (OVX) rats. The results were compared with those obtained after treatment of OVX rats with estrogen alone or a combination of estrogen and tamoxifen. OVX resulted in increases in growth rate (weight gain) and periosteal bone formation rate and decreases in uterine weight and cancellous bone fractional volume (BV/TV). Treatment of OVX rats with estrogen resulted in dose-dependent decreases in growth rate and periosteal bone formation rate as well as dose-dependent increases in uterine weight and BV/TV. Similarly, tamoxifen treatment resulted in dose-dependent decreases in overall growth rate and periosteal bone formation rate in both OVX and intact rats. Tamoxifen treatment prevented the decrease in BV/TV after OVX, although the highest dose of tamoxifen resulted in a small decrease in BV/TV in intact female rats. In contrast to estrogen, tamoxifen treatment prevented the increase in uterine weight in intact female rats as well as the decrease in uterine weight in OVX rats. Tamoxifen treatment did not alter the effects of 17 beta-estradiol on the periosteal bone formation rate in OVX rats, but reduced the increase in BV/TV to values similar to those in intact rats. These results are consistent with tamoxifen behaving as a partial estrogen agonist on rat bone.     

Binge alcohol treatment increases vertebral bone loss following ovariectomy: compensation by intermittent parathyroid hormone

BACKGROUND: Postmenopausal estrogen deficiency and alcohol abuse are known risk factors for osteoporosis. Previous studies of the combined effect of alcohol and ovariectomy on bone loss using chronic alcohol-feeding models have not demonstrated additional alcohol-induced bone loss in ovariectomized (OVX) animals. Binge alcohol treatment causes rapid bone loss in male rats. We hypothesized that binge alcohol would cause additional bone loss in OVX rats. METHODS: Ninety-six adult (400 g) female Sprague-Dawley rats (48 sham-operated and 48 OVX, pair fed) were randomly divided into 4 treatment groups: (a) saline-treated, (b) binge alcohol-treated (3 g/kg alcohol as a 20% weight to volume alcohol/saline solution, intraperitoneal (IP), 3 times per week), (c) parathyroid hormone (PTH)-treated (80 microg/kg, SC, 5 d/wk), and (d) binge alcohol plus PTH. Rats were treated for either 2 or 4 weeks. Following treatment periods, blood was collected for alcohol concentration (BAC) measurements; lumbar vertebrae were removed for bone mineral density (BMD) levels, trabecular microarchitecture assessment, and vertebral compressive strength analysis. RESULTS: Peak binge BACs averaged 300 mg/dL. Alcohol and OVX decreased cancellous BMD: alcohol and OVX treatment in combination caused additional cancellous BMD loss and significant cortical BMD reductions. Compressive strength was also decreased by OVX and alcohol. Combination treatment resulted in further declines in bone strength. Micro-CT analysis revealed a significant effect of combined OVX and alcohol treatment resulting in decreased trabecular bone volume/total volume (BV/TV). Intermittent PTH administration compensated for losses of BMD, compressive strength, and restored BV/TV deficits caused by OVX, alcohol, or their combination. CONCLUSIONS: Bone loss following OVX can be significantly increased by concurrent binge alcohol treatment. The effects of alcohol and OVX are compensated by concurrent intermittent treatment with PTH. These results suggest that postmenopausal women who abuse alcohol may place their skeleton at additional risk for osteoporotic fracture.     

Lasofoxifene, a next generation estrogen receptor modulator: preclinical studies

Estrogen replacement therapy, in spite of efficacy in the prevention of osteoporotic fractures, has significant side effects and risks that limit its widespread usage in postmenopausal women. Thus significant medical need exists to find modalities that prevent osteoporosis, but without the side effects of estrogen. Selective estrogen receptor modulators (SERMs) have the potential to provide the skeletal benefits of estrogen without the increased risk of uterine and breast cancer. Tamoxifen, a first generation SERM is approved for the prevention and treatment of breast cancer, and raloxifene, a second generation SERM has been approved for the prevention and treatment of osteoporosis. Lasofoxifene, a new potent, nonsteroidal SERM, binds with high affinity to human estrogen receptors and acts as a tissue selective estrogen antagonist or agonist. In preclinical models of postmenopausal osteoporosis, lasofoxifene inhibited bone turnover and prevented bone loss throughout the skeleton. In studies designed to investigate the combination of lasofoxifene with estrogen, lasofoxifene blocked the hypertrophic effects of estrogen in the uterus, but did not block the bone protective effects. In immature and aged female rats, lasofoxifene did not affect the uterine weight and uterine histology. In preclinical studies designed to evaluate the effects of lasofoxifene on the uterus, a slight increase in wet uterine weight was observed in immature and aged female rats, but this difference was not observed in dry uterine weight suggesting that the increased uterine weight was due to increased water content in the tissue. In preclinical studies designed to evaluate the effects of lasofoxifene in breast cancer, lasofoxifene inhibited breast tumor formation in mice injected with human MCF-7 breast cancer cells and in rats bearing mammary carcinomas. Thus, in preclinical models, lasofoxifene, a next generation SERM, prevents estrogen deficiency-induced bone loss, inhibits breast tumor formation, and reduces serum cholesterol, without causing uterine hypertrophy. These data suggest that lasofoxifene is a new potential therapy for the prevention of osteoporosis in postmenopausal women.     

复方淫羊藿对去卵巢大鼠腰椎松质骨的影响

目的 观察淫羊藿提取物与乙烯雌酚（DES）组成复方淫羊藿对去卵巢大鼠腰椎松质骨的影响。方法 4.5月龄SD雌性大鼠70只，随机分成假手术组、去卵巢组、DES组、淫羊藿提取物组、复方淫羊藿高、中、低剂量组，持续给药90d。大鼠处死后用骨组织形态计量学等方法测量腰椎松质骨的动态参数和静态参数，同时测量子宫内膜厚度。结果 复方淫羊藿3个剂量组的腰椎％TbAr、Tb.Th均高于去卵巢组，而Tb.Sp、Oe.N、BFR／BV均低于去卵巢组。复方淫羊藿商剂量组的作用比单用DES强，而低剂量组的作用与DES相当。复方淫羊藿3个剂量组子宫重量、子宫内膜厚度均高于去卵巢组，但子宫内膜厚度均小予DES组。结论 复方淫羊藿预防去卵巢大鼠腰椎松质骨丢失的作用强于DES，对子宫刺激的作用比DES小。     

Long-term treatment of lasofoxifene preserves bone mass and bone strength and does not adversely affect the uterus in ovariectomized rats

The purpose of this study was to determine the long-term effects of lasofoxifene, a new selective estrogen receptor modulator, on bone mass, bone strength, and reproductive tissues in ovariectomized (OVX) rats. Sprague Dawley female rats at 3.5 months of age were OVX and treated orally with lasofoxifene (60, 150, or 300 microg/kg x d) for 52 wk. The urinary deoxypyridinoline/creatinine ratio was significantly lower in all lasofoxifene-treated OVX rats compared with OVX controls at wk 26. Peripheral quantitative computerized tomography analysis of proximal tibial metaphysis showed that the significant loss in trabecular content and density induced by OVX was significantly prevented by lasofoxifene treatment. Proximal tibial and lumber vertebral trabecular bone histomorphometric analysis showed that all doses of lasofoxifene significantly reduced OVX-induced bone loss by decreasing bone resorption and bone turnover. The ultimate strength, energy, and toughness of the fourth lumbar vertebral body in OVX rats treated with all doses of lasofoxifene were significantly higher compared with those in OVX controls, and did not differ significantly from those in sham controls. Uterine weight in OVX rats treated with lasofoxifene was slightly, but significantly, higher when compared with that in OVX controls, but was still much less than that in sham controls. No abnormal finding associated with lasofoxifene was observed with uterine histology examination. In summary, long-term treatment with lasofoxifene preserves bone mass and bone strength and does not adversely affect the uterus in OVX rats. These data suggest that lasofoxifene is an effective antiosteoporosis agent, and its efficacy and safety can be maintained over an extended period of time.     

Additive effects of raloxifene and alendronate on bone density and biochemical markers of bone remodeling in postmenopausal women with osteoporosis

Both raloxifene (RLX) and alendronate (ALN) can treat and prevent new vertebral fractures, increase bone mineral density (BMD), and decrease biochemical markers of bone turnover in postmenopausal women with osteoporosis. This phase 3, randomized, double-blind 1-yr study assessed the effects of combined RLX and ALN in 331 postmenopausal women with osteoporosis (femoral neck BMD T-score, less than -2). Women (aged < or = 75 yr; > or = 2 yr since their last menstrual period) received placebo, RLX 60 mg/d, ALN 10 mg/d, or RLX 60 mg/d and ALN 10 mg/d combined. At baseline, 6 and 12 months, BMD was measured by dual x-ray absorptiometry. The bone turnover markers serum osteocalcin, bone-specific alkaline phosphatase, and urinary N- and C-telopeptide corrected for creatinine were measured. The effects of RLX and ALN were considered to be independent and additive if the interaction effect was not statistically significant (P > 0.10) in a two-way ANOVA model. All changes in BMD and bone markers at 12 months were different between placebo and each of the active treatment groups, and between the RLX and RLX+ALN groups (P < 0.05). On average, lumbar spine BMD increased by 2.1, 4.3, and 5.3% from baseline with RLX, ALN, and RLX+ALN, respectively. The increase in femoral neck BMD in the RLX+ALN group (3.7%) was greater than the 2.7 and 1.7% increases in the ALN (P = 0.02) and RLX (P < 0.001) groups, respectively. The changes from baseline to 12 months in bone markers ranged from 7.1 to -16.0% with placebo, -23.8 to -46.5% with RLX, -42.3 to -74.2% with ALN, and -54.1 to -81.0% in the RLX+ALN group. RLX and ALN increased lumbar spine and femoral neck BMD, and decreased osteocalcin and C-telopeptide corrected for creatinine in an additive and independent manner, because the interaction effects were not significant. Although the ALN group had changes in BMD and bone markers that were approximately twice the magnitude as in the RLX group, it is not known how well these changes correlate to the clinical outcome of fracture. RLX+ALN reduced bone turnover more than either drug alone, resulting in greater BMD increment, but whether this difference reflects better fracture risk reduction was not assessed in this study.     

Combination treatment with pioglitazone and fenofibrate attenuates pioglitazone-mediated acceleration of bone loss in ovariectomized rats

Peroxisome proliferator-activated receptor (PPAR) γ agonists, such as pioglitazone (Pio), improve glycemia and lipid profile but are associated with bone loss and fracture risk. Data regarding bone effects of PPARα agonists (including fenofibrate (Feno)) are limited, although animal studies suggest that Feno may increase bone mass. This study investigated the effects of a 13-week oral combination treatment with Pio (10?mg/kg per day)+Feno (25?mg/kg per day) on body composition and bone mass parameters compared with Pio or Feno alone in adult ovariectomized (OVX) rats, with a 4-week bone depletion period, followed by a 6-week treatment-free period. Treatment of OVX rats with Pio+Feno resulted in ～50% lower fat mass gain compared with Pio treatment alone. Combination treatment with Pio+Feno partially prevented Pio-induced loss of bone mineral content (～45%) and bone mineral density (BMD; ～60%) at the lumbar spine. Similar effects of treatments were observed at the femur, most notably at sites rich in trabecular bone. At the proximal tibial metaphysis, concomitant treatment with Pio+Feno prevented Pio exacerbation of ovariectomy-induced loss of trabecular bone, resulting in BMD values in the Pio+Feno group comparable to OVX controls. Discontinuation of Pio or Feno treatment of OVX rats was associated with partial reversal of effects on bone loss or bone mass gain, respectively, while values in the Pio+Feno group remained comparable to OVX controls. These data suggest that concurrent/dual agonism of PPARγ and PPARα may reduce the negative effects of PPARγ agonism on bone mass.     

葛根素对去卵巢大鼠机体骨代谢影响的观察

目的 观察葛根素对去卵巢大鼠机体骨代谢的影响,探讨其对雌激素缺乏引起的骨质疏松症的治疗作用.方法 3月龄清洁级SD大鼠60只,背驮式切除双侧卵巢后每日灌胃葛根素5 mg/kg(P-5组),10 mg/kg(P-10组)和20 mg/kg(P-20组),并设假手术组(Sham),模型组(OVX)和己烯雌酚阳性对照组(E).3个月后处死动物,测定大鼠胫骨干重、灰分重量和矿物质含量,胫骨Ca、P含量以及血清相关骨代谢指标.结果 与OVX组相比,葛根素各组的胫骨矿物质含量(mg/g)均有增加(574±17,590±22和597±18),其中P-20组差异显著(P＜0.05);葛根素各组的胫骨Ca含量(mg/g)高于OVX组 (132±10,222±7,228±8),其中P-10,P-20两组差异显著(P＜0.05,P＜0.01),说明服用葛根素后大鼠骨量得到增加;同时,葛根素各组的碱性磷酸酶(U/L)与OVX组有所降低(101±26,90±20,71±15),其中P-10,P-20两组差异显著(P＜0.05,P＜0.01),说明去卵巢大鼠骨的高转换状态得到改善.结论 葛根素能抑制去卵巢大鼠骨量的丢失,对骨代谢有较好的调节作用,对雌激素缺乏引起的骨质疏松症有一定的治疗作用.     

The catechol estrogen, 4-hydroxyestrone, has tissue-specific estrogen actions

Recent data indicate that the catechol estrogen, 2-hydroxyestrone (2-OHE(1)), has no effect on any target tissue including bone, whereas 16 alpha-hydroxyestrone (16 alpha-OHE(1)) exerts tissue-selective estrogen agonist activity. The effect of the catechol estrogen, 4-hydroxyestrone (4-OHE(1)), putatively associated with tumorigenesis, has not been studied in the skeleton. The purpose of this study was to assess the effect of 4-OHE(1) on tibia, uterine and mammary gland histology and blood cholesterol in ovariectomized (OVX'd) growing rats. Ten-week-old female Sprague-Dawley rats were injected subcutaneously with 200 microg/kg BW per day with 4-OHE(1), 17 beta-estradiol (E(2)) or vehicle for three weeks. OVX resulted in uterine atrophy, increased body weight, radial bone growth and cancellous bone turnover, and hypercholesterolemia. E(2) prevented these changes with the expected exception that the subcutaneous infusion of this high dose of estrogen did not prevent the hypercholesterolemia. 4-OHE(1) prevented the increase in blood cholesterol and the increase in body weight. 4-OHE(1) appeared to have partial estrogen activity in the uterus; uterine weight and epithelial cell height were significantly greater than the OVX rats but significantly less (twofold) than the E(2) animals. Analysis of variance indicated that 4-OHE(1) slightly decreased the periosteal mineral apposition rate (P<0.05) compared with vehicle-treated rats but had no effect on double-labeled perimeter or bone formation rate. Similarly, 4-OHE(1) was a partial estrogen agonist on cancellous bone turnover. The data suggest that the catechol estrogen, 4-OHE(1), unlike 2-OHE(1), has estrogen activity. Furthermore, the profile of activity differs from that of 16 alpha-OHE(1). Our results suggest that estrogen metabolites may selectively influence estrogen-target tissues and, concomitantly, modulate estrogen-associated disease risk.