Ohmori S, Kanda K, Kawano S, Kambe F, Seo H
Department of Endocrinology and Metabolism, Division of Molecular and Cellular Adaptation, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
Environ Med. 2001 Dec;45(1):12-4.
It is known that estrogen deficiency results in osteoporosis in human and experimental animals. However, how this deficiency affects the development of disuse bone atrophy is not well understood. Recently, it has been reported that estrogen affects the production of cytokines such as interleukin 6 (IL-6) which acts as local bone-resorbing factor. We thus studied how estrogen deficiency caused by ovariectomy and estrogen supplements affects the expression of IL-6 mRNA in the femur of tail-suspended rats. Five-week old female Wistar rats were ovariectomized and divided into two groups. One group received an intramuscular injection of estradiol dipropionate once a week (OVX-E2 group), and the other received the vehicle alone (OVX group). After the third injection, the rats were subjected to tail suspension in metabolic cages for 1, 3, 5 and 7 days. The wet weight of femurs significantly decreased after day 3 of tail-suspension in the OVX group. However, no significant decrease was observed in the OVX-E2 group. The expression of IL-6 mRNA estimated by RT-PCR (reverse transcription coupled polymerase chain reaction) in the femur significantly increased on day 5 after tail suspension in the OVX group. In the OVX-E2 group, that level significantly decreased on day 1 after the commencement of tail suspension. During suspension the level tended to be lower than that in the OVX group, a significant difference being observed on days 5 and 7 of suspension. The present results suggest that estrogen administration to OVX rats prevents both IL-6 production in the femur and the development of disuse bone atrophy induced by tail suspension.
已知雌激素缺乏会导致人类和实验动物出现骨质疏松症。然而，这种缺乏如何影响废用性骨萎缩的发展尚不清楚。最近，有报道称雌激素会影响细胞因子的产生，如作为局部骨吸收因子的白细胞介素6（IL-6）。因此，我们研究了卵巢切除引起的雌激素缺乏和雌激素补充剂如何影响尾部悬吊大鼠股骨中IL-6 mRNA的表达。将5周龄的雌性Wistar大鼠进行卵巢切除，并分为两组。一组每周接受一次二丙酸雌二醇的肌肉注射（OVX-E2组），另一组仅接受赋形剂（OVX组）。第三次注射后，将大鼠置于代谢笼中进行尾部悬吊1、3、5和7天。OVX组在尾部悬吊第3天后股骨湿重显著降低。然而，OVX-E2组未观察到显著降低。通过RT-PCR（逆转录偶联聚合酶链反应）估计的股骨中IL-6 mRNA的表达在OVX组尾部悬吊第5天时显著增加。在OVX-E2组中，该水平在尾部悬吊开始后第1天显著降低。在悬吊期间，该水平倾向于低于OVX组，在悬吊第5天和第7天观察到显著差异。目前的结果表明，给OVX大鼠施用雌激素可防止股骨中IL-6的产生以及尾部悬吊诱导的废用性骨萎缩的发展。
