目的:本研究旨在阐明甲状旁腺激素(PTH)的给药是否会导致鼠股骨不同区域的基于重塑或建模的骨形成,以及PTH驱动的骨形成是否会促进成骨细胞分化为骨细胞。
方法:采用6周龄雄性C57BL/6J小鼠检测碱性磷酸酶(ALP)的分布,PHOSPHO1,podoplanin,和钙黄绿素标记在两个不同的长骨区域:三个小鼠组中靠近软骨-骨交界处(COJ)的干phy端小梁和远离COJ的小梁,接受媒介物的对照组(Sham组)和每天两次(PTHBID组)或每天四次(PTHQID组)接受hPTH(1-34)的组,持续两周。
结果:Sham组显示PHOSPHO1反应性成熟成骨细胞主要位于COJ,而PTHBID/QID组即使在远离COJ的区域也显示出PHOSPHO1反应性成骨细胞的延长线。PTHQID组在靠近COJ的小梁中显示出片段的钙黄绿素标记,而在远离COJ的小梁中观察到连续标记。成骨细胞倾向于在Sham组的近区和远区独立表达podoplanin和PHOSPHO1,而PTH给药组的成骨细胞在近距离和远距离区域显示出podoplanin和PHOSPHO1的免疫反应性。
结论:PTH的给药可加速靠近COJ区域的基于重塑的骨形成,同时主要诱导远处区域的基于建模的骨形成。在基于重塑和建模的骨形成中,PTH似乎同时促进成骨细胞骨矿化和分化为骨细胞。
OBJECTIVE: This study aimed to elucidate whether the administration of parathyroid hormone (PTH) results in remodeling- or modeling-based bone formation in different regions of the murine femora, and whether the PTH-driven bone formation would facilitate osteoblastic differentiation into osteocytes.
METHODS: Six-week-old male C57BL/6J mice were employed to examine the distribution of alkaline phosphatase (ALP), PHOSPHO1, podoplanin, and calcein labeling in two distinct long bone regions: the metaphyseal trabeculae close to the chondro-osseous junction (COJ) and those distant from the COJ in three mouse groups, a control group receiving a vehicle (sham group) and groups receiving hPTH (1-34) twice a day (PTH BID group) or four times a day (PTH QID group) for two weeks.
RESULTS: The sham group showed PHOSPHO1-reactive mature osteoblasts localized primarily at the COJ, whereas the PTH BID/QID groups exhibited extended lines of PHOSPHO1-reactive osteoblasts even in regions distant from the COJ. The PTH QID group displayed fragmented calcein labeling in trabeculae close to the COJ, whereas continuous labeling was observed in trabeculae distant from the COJ. Osteoblasts tended to express podoplanin and PHOSPHO1 independently in the close and distant regions of the sham group, while osteoblasts in the PTH-administered groups showed immunoreactivity of podoplanin and PHOSPHO1 together in the close and distant regions.
CONCLUSIONS: Administration of PTH may accelerate remodeling-based bone formation in regions close to the COJ while predominantly inducing modeling-based bone formation in distant regions. PTH appeared to simultaneously facilitate osteoblastic bone mineralization and differentiation into osteocytes in both remodeling- and modeling-based bone formation.