Yeh J K, Liu C C, Aloia J F
Department of Medicine, Winthrop-University Hospital, Mineola, New York.
J Bone Miner Res. 1993 Jun;8(6):677-83. doi: 10.1002/jbmr.5650080605.
The effects of 17 beta-estradiol (E2) and treadmill exercise on tibial bone mass, tibial uptake of 45Ca, and proximal tibia osteoblast and osteoclast cell number were determined in adult ovariectomized rats. Female rats aged 10 months were ovariectomized and divided into five groups: (1) sham-operated; (2) ovariectomized; (3) ovariectomized, given 10 micrograms E2 biweekly; (4) ovariectomized, trained to exercise on a treadmill daily; and (5) ovariectomized, given E2 and exercised. E2 and/or exercise interventions were started 2 months following surgery and continued for 4 months. The calcium content of the tibial metaphysis and diaphysis and the proximal cancellous bone (BV/TV) were lower in the ovariectomized than in the sham-operated controls 6 months after ovariectomy. This lower bone content was associated with a greater bone uptake of 45Ca and a greater number of osteoblasts and osteoclasts in the proximal tibia compared to the control rats. The metaphyseal calcium content was higher and the 45Ca uptake and osteoblast and osteoclast number were lower in the E2-treated rats than in the nontreated rats. In the exercised group, higher diaphyseal calcium content and proximal cancellous bone were associated with lower bone resorption parameters without a significant effect on bone formation. This study demonstrates that E2 primarily influences tibial cancellous bone of the ovariectomized rat and a positive adaptation to exercise occurs in both cancellous and cortical bone. Under estrogen deficiency, E2 replacement suppresses increased bone formation and resorption; exercise suppresses mainly bone resorption. The effects of E2 replacement and exercise training are independent and additive.
在成年去卵巢大鼠中，研究了17β-雌二醇（E2）和跑步机运动对胫骨骨量、胫骨45Ca摄取以及胫骨近端成骨细胞和破骨细胞数量的影响。将10月龄雌性大鼠去卵巢，并分为五组：（1）假手术组；（2）去卵巢组；（3）去卵巢组，每两周给予10微克E2；（4）去卵巢组，每天训练在跑步机上运动；（5）去卵巢组，给予E2并进行运动。E2和/或运动干预在手术后2个月开始，持续4个月。去卵巢6个月后，去卵巢组胫骨干骺端和骨干以及近端松质骨（骨体积/组织体积）的钙含量低于假手术对照组。与对照大鼠相比，这种较低的骨含量与胫骨近端45Ca摄取增加以及成骨细胞和破骨细胞数量增多有关。E2治疗组的干骺端钙含量较高，45Ca摄取以及成骨细胞和破骨细胞数量低于未治疗组。在运动组中，较高的骨干钙含量和近端松质骨与较低的骨吸收参数相关，对骨形成无显著影响。本研究表明，E2主要影响去卵巢大鼠的胫骨松质骨，并且在松质骨和皮质骨中均出现对运动的正向适应性变化。在雌激素缺乏的情况下，E2替代可抑制增加的骨形成和骨吸收；运动主要抑制骨吸收。E2替代和运动训练的作用是独立且相加的。
