Jiang Jessica M Y, Sacco Sandra M, Ward Wendy E
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 3E2.
J Nutr. 2008 Nov;138(11):2106-10. doi: 10.3945/jn.108.093781.
The ovariectomized (OVX) rat is a widely used animal model for the development of prevention and treatment strategies for postmenopausal osteoporosis. However, ovariectomy-induced hyperphagia results in weight gain and adiposity. To prevent potential protective effects of increased body weight on bone from confounding outcomes of preclinical studies, pair-feeding is used in some but not all studies to control food intake, but its importance is not well elucidated. We investigated if the type of feeding, pair-feeding vs. consumption of diet ad libitum, modulates bone mineral and bone strength in OVX rats. Three-month-old female Sprague-Dawley rats (n = 12/group) were randomized to 1) sham-operated control (SHAM); 2) OVX pair-fed (OVX-PF); and 3) OVX ad libitum (OVX-AL). For 14 wk, OVX-PF rats were pair-fed with the SHAM group and daily food intakes and weekly body weights were obtained. At necropsy, regional body composition was measured by dual energy X-ray absorptiometry. Bone mineral density (BMD) and biomechanical bone strength of femurs and lumbar vertebrae (LV) were also measured. OVX-AL rats had higher overall food intake (P < 0.01), final body weight (P < 0.01), weight gain (P < 0.01), and fat mass (P < 0.05) than either SHAM and OVX-PF rats. Conversely, SHAM rats had higher femur (P < 0.001) and LV1-3 BMD (P < 0.001) as well as LV4 peak load (P < 0.01) than both the OVX groups, whereas bone outcomes did not differ between the OVX-PF and OVX-AL groups. In summary, ovariectomy-induced hyperphagia and weight gain do not modulate BMD or biomechanical strength at 14 wk postovariectomy, suggesting that pair-feeding is not essential.
卵巢切除（OVX）大鼠是一种广泛应用于绝经后骨质疏松症防治策略研究的动物模型。然而，卵巢切除引起的摄食亢进会导致体重增加和肥胖。为防止体重增加对骨骼产生的潜在保护作用混淆临床前研究结果，一些（但并非所有）研究采用配对喂养来控制食物摄入量，但其重要性尚未得到充分阐明。我们研究了喂养方式（配对喂养与自由摄食）是否会调节OVX大鼠的骨矿物质和骨强度。将3月龄雌性Sprague-Dawley大鼠（每组n = 12只）随机分为1）假手术对照组（SHAM）；2）OVX配对喂养组（OVX-PF）；3）OVX自由摄食组（OVX-AL）。在14周内，OVX-PF组大鼠与SHAM组进行配对喂养，并记录每日食物摄入量和每周体重。尸检时，通过双能X线吸收法测量局部身体成分。还测量了股骨和腰椎（LV）的骨矿物质密度（BMD）和生物力学骨强度。OVX-AL组大鼠的总体食物摄入量（P < 0.01）、终末体重（P < 0.01）、体重增加量（P < 0.01）和脂肪量（P < 0.05）均高于SHAM组和OVX-PF组大鼠。相反，SHAM组大鼠的股骨（P < 0.001）和LV1-3的BMD（P < 0.001）以及LV4的峰值负荷（P < 0.01）均高于两个OVX组，而OVX-PF组和OVX-AL组之间的骨指标没有差异。总之，卵巢切除引起的摄食亢进和体重增加在卵巢切除后14周时并未调节BMD或生物力学强度，这表明配对喂养并非必要。
