Treadmill training prevents bone loss by inhibition of PPARγ expression but not promoting of Runx2 expression in ovariectomized rats
Treadmill training prevents bone loss by inhibition of PPARγ expression but not promoting of Runx2 expression in ovariectomized rats
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DOI：
10.1007/s00421-010-1820-0
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发表时间：
2011-08-01
影响因子：
3
通讯作者：
Yang, Shaofeng
中科院分区：
文献类型：
--
作者：
Chen, Yongjie;Wang, Shouhui;Yang, Shaofeng
据报道，运动训练可以预防去卵巢(OVX)大鼠和绝经后妇女的骨丢失。我们假设在OVX诱导的骨质疏松模型中，跑步机训练通过调节脂肪细胞分化因子过氧化体增殖物激活受体γ(PPARγ)和成骨因子Runt相关转录因子2(Runx2)来抑制脂肪生成和促进成骨。为了验证这一假设，将3月龄雌性SD大鼠随机分为假手术组、去卵巢组、去卵巢运动组和去卵巢雌激素替代组(E组)。实验结束后，用双能X线骨密度仪测定骨密度，HE染色观察骨组织和子宫的形态变化。免疫组织化学和免疫印迹法检测PPAR-γ和Runx2蛋白表达，并用甲醇/氯仿提取骨三酰甘油(TG)。OVX显著增加胫骨和腰椎脂肪空泡数量、PPAR-γ和Runx2蛋白水平以及TG水平。OVX组血清E(2)水平、腰椎骨密度、股骨近端和远端骨密度均显著降低。运动治疗后，除Runx2蛋白表达水平外，OVX引起的所有改变均被运动治疗显著逆转。此外，从子宫湿重和组织学来看，运动治疗对子宫没有雌激素效应。跑台训练可能通过抑制脂肪细胞分化因子PPAR-γ而不是促进成骨因子Runx2来预防OVX所致的骨丢失。
Exercise training has been reported to prevent bone loss in ovariectomized (OVX) rats and postmenopausal women. We hypothesized that treadmill training inhibited adipogenesis and enhanced osteogenesis through the regulation of adipocyte differentiation factor peroxisome proliferators-activated receptor gamma (PPAR gamma) and the osteogenic factor runt-related transcription factor 2 (Runx2) in a model of OVX-induced osteoporosis. To test this hypothesis, 3-month-old female Sprague-Dawley rats were divided randomly into the following groups: Sham, OVX, OVX exercised (EX), and OVX estrogen replacement (E(2)). At the end of the experiment, the bone mineral density (BMD) was detected using DEXA and the morphology change of bone tissues and uterus was observed by HE staining. The protein expression for PPAR gamma and Runx2 were measured by immunohistochemistry and western blot and the bone triacylglycerol (TG) was extracted by methanol/chloroform. OVX dramatically increased the number of fat vacuoles, protein levels for PPAR gamma and Runx2 as well as the TG level in tibiae and lumbar vertebrate. In contrast, the serum level of E(2), the lumbar vertebrate BMD as well as the proximal and distal femur BMD was significantly decreased in the OVX group. All changes induced by OVX were significantly reversed by exercise treatment except for the protein expression level of Runx2. Moreover, exercise treatment produced no estrogenic effects on uterus as evidenced by the uterus wet weight and histology. Treadmill training could prevent bone loss induced by OVX through the inhibition of adipocyte differentiation factor PPAR gamma rather than promoting osteogenic factor Runx2.