Cui Hongwang, Zhu Yongjun, Jiang Dianming
Department of Orthopaedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
Department of Nephrology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
PLoS One. 2016 Mar 17;11(3):e0150805. doi: 10.1371/journal.pone.0150805. eCollection 2016.
Osteocyte apoptosis has been reported to play a central role in bone remodeling. In addition to apoptosis, other mechanisms may be involved in osteocyte loss. This study aimed to investigate the effect of necroptosis on osteocytes in ovariectomized (OVX) rats. Ninety-six female Sprague-Dawley rats were randomly divided into an OVX group and a sham group. At 0, 4, 8 and 12 weeks after surgery, specimens from each group (n = 12 each) were harvested. Bone mineral density (BMD) and body weight were measured. Transmission electron microscopy (TEM) and micro-CT were used to observe the changes in cellular morphology and bone microarchitecture induced by estrogen deficiency. Osteocyte apoptosis and necroptosis were evaluated via TUNEL and immunofluorescence staining for active caspase-3. At 8 weeks after ovariectomy, a greater number of osteocytes with typical necrotic morphological features were TUNEL positive but negative for active caspase-3. Western blotting, quantitative real-time PCR and immunofluorescence assessments demonstrated that the levels of receptor-interacting serine/threonine protein kinase 1 (RIP1) and RIP3 in osteocytes were significantly increased at 8 weeks after ovariectomy. These data are the first to suggest that necroptosis accelerates osteocyte loss under conditions of estrogen deficiency-induced osteoporosis in OVX rats. These findings provide evidence of a potential mechanism through which osteocyte necroptosis is associated with postmenopausal osteoporosis.
据报道，骨细胞凋亡在骨重塑中起核心作用。除了凋亡外，其他机制可能也参与了骨细胞的丢失。本研究旨在探讨坏死性凋亡对去卵巢（OVX）大鼠骨细胞的影响。将96只雌性Sprague-Dawley大鼠随机分为OVX组和假手术组。在术后0、4、8和12周，收集每组的标本（每组n = 12）。测量骨密度（BMD）和体重。采用透射电子显微镜（TEM）和显微CT观察雌激素缺乏引起的细胞形态和骨微结构变化。通过TUNEL和活性半胱天冬酶-3免疫荧光染色评估骨细胞凋亡和坏死性凋亡。去卵巢8周后，大量具有典型坏死形态特征的骨细胞TUNEL阳性，但活性半胱天冬酶-3阴性。蛋白质免疫印迹法、定量实时PCR和免疫荧光评估表明，去卵巢8周时骨细胞中受体相互作用丝氨酸/苏氨酸蛋白激酶1（RIP1）和RIP3的水平显著升高。这些数据首次表明，在OVX大鼠雌激素缺乏诱导的骨质疏松症条件下，坏死性凋亡加速了骨细胞的丢失。这些发现为骨细胞坏死性凋亡与绝经后骨质疏松症相关的潜在机制提供了证据。
