Reduced RANKL expression impedes osteoclast activation and tooth eruption in alendronate-treated rats
Reduced RANKL expression impedes osteoclast activation and tooth eruption in alendronate-treated rats
复制标题
DOI：
10.1007/s00441-013-1623-9
复制
发表时间：
2013-07-01
影响因子：
3.6
通讯作者：
Arana-Chavez, Victor E.
中科院分区：
文献类型：
--
作者：
Bradaschia-Correa, Vivian;Moreira, Mariana M.;Arana-Chavez, Victor E.
萌出途径的建立需要破骨细胞对咬合牙槽骨的吸收，骨和牙囊之间的信号传递是必要的。本研究的目的是评价阿伦磷酸钠对破骨细胞生成的影响以及破骨细胞激活的调节蛋白RANK、RANKL和OPG在覆盖第一磨牙胚骨中的表达。新生Wistar大鼠每日给予阿仑磷酸钠2.5 mg/kg，连续4、8、14、21、28天，对照组给予无菌生理盐水。在上述时间点，固定上颌骨，脱钙，并进行光镜和电子显微镜分析。半连续切片行TRAP组织化学染色，计数骨隐窝表面咬合区破骨细胞。对石蜡切片进行TUNEL分析。分别于4d和8日龄阿伦磷酸钠治疗组和对照组去除覆盖上颌第一磨牙的咬合骨，用SDS-聚丙烯酰胺凝胶电泳法和Western blotting分析RANK、RANKL和OPG的表达。尽管有未激活的表型和凋亡细胞的存在，但在阿伦磷酸组中，TRAP阳性的破骨细胞在所有时间点上都更多。与对照组不同，阿伦磷酸钠样本中RANKL的表达在所有时间点都受到抑制。我们的研究结果表明，RANKL在骨隐窝咬合部分的表达与破骨细胞的募集和分化无关，但在萌出途径的建立过程中对破骨细胞的激活至关重要。
The creation of the eruption pathway requires the resorption of the occlusal alveolar bone by osteoclasts and signaling events between bone and dental follicle are necessary. The aim of the present study has been to evaluate the effect of alendronate on osteoclastogenesis and the expression of the regulator proteins of osteoclast activation, namely RANK, RANKL and OPG, in the bone that covers the first molar germ. Newborn Wistar rats were treated daily with 2.5 mg/kg alendronate for 4, 8, 14, 21 and 28 days, whereas controls received sterile saline solution. At the time points cited, maxillae were fixed, decalcified and processed for light and electron microscopic analysis. TRAP histochemistry was performed on semi-serial sections and the osteoclasts in the occlusal half of the bony crypt surface were counted. TUNEL analysis was carried out on paraffin sections. The occlusal bone that covers the upper first molar was removed in additional 4- and 8-day-old alendronate-treated and control rats in which the expression of RANK, RANKL and OPG was analyzed by SDS-polyacrylamide gel electrophoresis and Western blotting. TRAP-positive osteoclasts were more numerous in the alendronate group at all time points, despite their unactivated phenotype and the presence of apoptotic cells. RANKL expression in the alendronate specimens was inhibited at all time points, unlike in controls. Our findings indicate that the expression of RANKL in the occlusal portion of the bony crypt is unrelated to osteoclast recruitment and differentiation but is crucial to their activation during the creation of the eruption pathway.