Centre of System Biomedical Sciences, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China.
Br J Nutr. 2010 Oct;104(7):965-71. doi: 10.1017/S0007114510001789. Epub 2010 May 21.
Our previous study showed that Erythrina variegata L. (EV) inhibited bone loss and improved bone properties in ovariectomised rats. The purpose of the present study is to investigate the potential mechanism involved in mediating the osteoprotective actions of EV. Female Sprague-Dawley rats were fed a phyto-oestrogen-free diet and subjected to either ovariectomy or a sham operation. Ovariectomised rats were treated with genistein (40 mg/kg) as well as low (200 mg/kg), medium (500 mg/kg) or high (1000 mg/kg) doses of EV extract. Bone properties and mRNA expressions were evaluated by micro-computed tomography and quantitative RT-PCR, respectively. Osteoclast differentiation in RAW 264.7 cells was studied by tartrate-resistant acid phosphatase (TRAP) staining. High doses of EV could decrease urinary Ca and P excretion, maintain serum Ca and P level, and exert beneficial effects on the micro-structure and morphology of trabecular bone and cortical bone in ovariectomised rats. EV suppressed the up-regulation of cathepsin K mRNA and the down-regulation of osteoprotegrin mRNA in the tibia of ovariectomised rats. TRAP-positive cell numbers were significantly decreased in receptor activator of nuclear factor-κB ligand (RANKL)-induced RAW 264.7 cells when co-cultured with EV extracts. The present study indicated that the protective effects of EV on bone properties in ovariectomised rats are likely to be mediated by its inhibitory actions on the process of bone resorption via the suppression of osteoclast differentiation and maturation.
我们之前的研究表明，刺桐（EV）抑制去卵巢大鼠的骨丢失并改善骨特性。本研究的目的是探讨介导 EV 骨保护作用的潜在机制。雌性 Sprague-Dawley 大鼠喂食不含植物雌激素的饮食，并接受卵巢切除术或假手术。去卵巢大鼠用染料木黄酮（40mg/kg）以及低（200mg/kg）、中（500mg/kg）或高（1000mg/kg）剂量的 EV 提取物治疗。通过微计算机断层扫描和定量 RT-PCR 分别评估骨特性和 mRNA 表达。通过抗酒石酸酸性磷酸酶（TRAP）染色研究 RAW 264.7 细胞中的破骨细胞分化。高剂量的 EV 可以减少尿钙和磷的排泄，维持血清钙和磷水平，并对去卵巢大鼠的小梁骨和皮质骨的微观结构和形态产生有益影响。EV 抑制了去卵巢大鼠胫骨中组织蛋白酶 K mRNA 的上调和骨保护素 mRNA 的下调。当与 EV 提取物共培养时，受体激活核因子-κB 配体（RANKL）诱导的 RAW 264.7 细胞中 TRAP 阳性细胞数显著减少。本研究表明，EV 对去卵巢大鼠骨特性的保护作用可能是通过抑制破骨细胞分化和成熟来抑制骨吸收过程来介导的。
