mRNA levels of proteins related to bone metabolism in the experimental osteoporosis of rats.

人类骨质疏松症的病因是多因素的，可由衰老、绝经后和固定等情况引起，也可由一般内分泌激素和局部生长因子和细胞因子的变化引起。我们研究了骨代谢相关蛋白的mRNA水平。以雌性Wistar大鼠为研究对象，采用卵巢切除和固定相结合的方法诱导实验性骨质疏松。行双侧坐骨神经切除术以固定后肢。大鼠口服1,25 (OH) 2D3或一种新的合成维生素D3类似物2-（3-羟基丙氧基）-1,25-二羟基维生素D3 [ED-71]，每周2次，并于1、2、4和8周处死。ED-71 0.2mug/kg处理组保留骨矿物质含量。1,25 (OH) 2D3 0.2杯子/kg和ED-71 0.2杯子/kg治疗组血清骨钙素水平在第4周和第8周升高。Northern blot杂交检测后肢骨中骨钙素mRNA水平，ED-71 0.2mug/kg处理组骨钙素mRNA水平持续升高。这些结果表明，ED-71不仅可以通过正常骨吸收，还可以通过刺激成骨细胞来预防骨质疏松性骨量减少。在大鼠骨肉瘤细胞（ROS 17/2.8）的体外实验中，在培养基中加入1,25 (OH) 2D3或ED-71时，骨钙素mRNA水平呈剂量依赖性增加。当细胞暴露于26,27- f6 -1,25 (OH) 2D3 [F6-D3] （1,25 (OH) 2D3类似物）时，骨钙素mRNA水平升高。在培养基中添加1,25 (OH) 2D3或F6-D3时，细胞中碱性磷酸酶mRNA和骨桥蛋白mRNA均升高。综上所述，1,25 (OH) 2D3和两种类似物直接刺激骨钙素、碱性磷酸酶和骨桥蛋白mRNA的表达。

Human osteoporosis is multifactorial in its etiology, and can result from such conditions as senility, post-menopause and immobilization, as well as changes in endoclinological hormones at general and growth factors and cytokines at local sites. We investigated the mRNA levels of proteins related in bone metabolism.Experimental osteoporosis was induced by a combination of ovariectomy and immobilization in female Wistar rats. Bilateral sciatic neurectomy was performed in order to immobilize the hind limbs. Rats were orally given 1,25 (OH) 2D3 or a new synthetic vitamin D3 analogue, 2- (3-hydroxypropoxy) -1,25-dihydroxyvitamin D3 [ED-71] twice a week and sacrificed at 1,2,4 and 8 weeks. Bone mineral content was preserved in the ED-71 0.2mug/kg treated group. Serum osteocalcin levels increased in the 1,25 (OH) 2D3 0.2mug/kg and ED-71 0.2mug/kg treated groups at 4 and 8 weeks. Osteocalcin mRNA levels in the bones of the hind limbs which was determined by Northern blot hybridization and increased consistently in the ED-71 0.2mug/kg treated group. These findings suggest that ED-71 may prevent the osteoporotic decrease of bone mass not only by normalizing bone resorption but also by stimulating osteoblasts.In the in vitro experiment using rat osteosarcoma cells (ROS 17/2.8), osteocalcin mRNA levels increased in a dose-dependent manner when either 1,25 (OH) 2D3 or ED-71 was added to the medium. Osteocalcin mRNA levels of the cells increased when they were exposed to 26,27-F6-1,25 (OH) 2D3 [F6-D3], (an analogue of 1,25 (OH) 2D3). Alkaline-phosphatase mRNA and osteopontin mRNA in the cells also increased when either 1,25 (OH) 2D3 or F6-D3 was added to the medium. In summary, 1,25 (OH) 2D3 and two analogues directly stimulated osteocalcin, alkaline-phosphatase and osteopontin mRNA expression.