雌孕激素合用对去卵巢骨质疏松大鼠的骨保护效果(英文)

Protective effects of a combination of estrogen and progestin on ovariectomized rats with osteoporosis

背景:有报道雌激素和孕激素联合应用对防治绝经后骨质疏松症有协同作用,且副作用较小。目的:观察炔诺酮和炔雌醇联合应用对去卵巢大鼠骨量的影响。设计:随机对照验证性实验观察。单位:广东医学院药理教研室。对象:清洁级4个半月龄未交配的雌性SD大鼠24只,体质量(230±15)g。方法:实验于2002-05/11在广东医学院药理教研究空完成。大鼠随机分成3组:假手术组,去卵巢组,复方炔诺酮组,每组8只,前2组采用体积分数为0.056的乙醇溶液5mL/(kg·d)灌胃,复方炔诺酮组采用炔诺酮60μg/(kg·d)和炔雌醇3.5μg/(kg·d)灌胃(实验用药剂量参照人的用药20～35μg雌激素+孕激素)。所有动物给药时间为90d。给药结束后取胫骨标本,采用全自动图像分析系统对胫骨近端次级骨小梁形成区进行破骨细胞和有关动静态参数的测量;另取肱骨标本用电感偶合等离子体直读光谱仪测定钙含量和测定羟脯氨酸含量。同时测定尿中的钙和羟脯氨酸的含量。主要观察指标:①各组大鼠骨小梁面积、骨小梁厚度、骨小梁数目、骨小梁分离度、破骨细胞周长的静态参数变化。荧光周长百分数、矿化沉积率、骨形成率动态参数变化。②血清碱性磷酸酶、骨和尿中钙含量和羟脯氨酸含量变化。结果:24只大鼠均进入结果分析。①去卵巢大鼠与假手术组大鼠相比,骨小梁面积百分数下降,骨小梁数目降低和骨小梁分离度增加,伴随明显的破骨细胞周长增加(P<0.01);骨形成指标明显增加:荧光周长百分数和矿化沉积率增加(P<0.05),骨形成率(BFR/BV)明显增加(P<0.01)。②复方炔诺酮组与去卵巢组比较,骨量和骨小梁数目增加,骨小梁面积增加82%和骨小梁数目增加83%(P<0.05),骨小梁分离度降低51%(P<0.05);破骨细胞周长降低52.5%(P<0.01);同时骨有机质含量增加和尿羟脯氨酸排出量减少(P<0.05)。结论:炔诺酮和炔雌醇联合应用可防治去卵巢大鼠骨质疏松,增加骨量和骨有机质含量,且不明显抑制骨形成。实验提供的药物剂量参照人的用量,20～35μg雌激素结合一种孕激素,其效果良好时即可提供一种最好的骨保护作用。

BACKGROUND: It has been reported that a combination of estrogen and progestin has a protective synergistic effect on osteoporosis with only little side effects. OBJECTIVE: This study was designed to investigate the effect of a combination of norethisterone and ethinyl estradiol (EE) on bone mass in ovariectomized rats. DESIGN: This study was a randomized controlled experiment. SETTING: It was conducted at the Department of Pharmacology of Guangdong Medical University. MATERIALS: Twenty-four specific pathogen free (SPF) unmated SD rats were selected, aging 4 and half months and weighing 230±15 g. METHODS: The experiment was conducted in the Department of Pharmacology of Guangdong Medical College from May to November 2002. These rats were randomly divided into 3 groups: pseudo-operation group, ovariectomy group and compound norethisterone group, each containing 8 rats. For the former two groups, ethanol solution (volume fraction=0.056), at a dose of 5 mL/(kg·d), was administered by gavage. While for compound norethisterone group, 60 μg/(kg·d) norethisterone and 3.5 μg /(kg·d) EE were given by gavage (according to the dosage for human, which was 20-35 μg EE combined with norethisterone). Duration of treatment was 90 days for all the animals. Then their tibias were removed. Employing a fully-automatic imaging analysis system, osteoclasts and the relevant dynamic and static parameters reflecting secondary trabeculaes formation region in proximal tibias were measured. Respectively, the humeral samples were removed and employing the palsma emission spectrograph of full-spectrum direct reading, calcium content and hydroxyproline content in bone samples were measured. Meanwhile, urine calcium and hydroxyproline concentrations were examined as well. MAIN OUTCOME MEASURES: ①The trabecular area (Tb.Ar), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb. Sp) and the changes in static parameters of perimeters of osteoclasts were investigated. Variance in percent labeled perimeter (L. Pm %), mineral apposition rate (MAR) and bone formation rate (BFR/BV) were also calculated. ②Changes in serum alkaline phosphatase (AKP), calcium and hydroxyproline contents in bone and urine were all measured. RESULTS: All the 24 rats entered the analysis procedure. Compared to pseudo-operation group, for the ovariectomy group, Tb.Ar and Tb.N decreased, Tb. Sp increased and osteoclast perimeter significantly increased (P < 0.01). Addtionally, the bone formation markers increased apparently with an increase in L. Pm % and MAR (P < 0.05) and a significant increase in BFR/BV (P < 0.01). Compared with the ovariectomy group, for the compound norethisterone group, the bone mass and the Tb.N increased, marked by an increase of 82% in Tb.Ar and an increase of 83% in Tb.N (P < 0.05), and the Tb.Sp decreased, marked by a decrease of 51% (P < 0.05). Meanwhile, there was a decrease of 52.5% in osteoblast perimeter (P < 0.01), an increase in organic bone matrix and a decrease in urine hydroxyproline (P < 0.05). CONCLUSION: A combination of estrogen and progestin has a protective synergistic effect on ovariectomized rats with osteoporosis, and it is capable of increasing the organic bone matrix without significant inhibitory effects on bone formation. The experimental dosage of the compound was calculated according to the clinical dosage, 20-35 μg estrogen combined with a progestin, which will yield optimal protective effects on bone sometimes.