目的:最近的报道表明,牙周韧带组织来源(PDL)细胞在正畸力加载过程中分泌硬化蛋白,分泌的硬化蛋白有助于骨代谢。然而,详细的机制知之甚少。这项研究的目的是确定PDL细胞如何影响骨形成。
方法:对大鼠牙周膜组织进行硬化蛋白免疫组化染色。培养的原代PDL细胞,成骨细胞,和从大鼠牙周膜组织中分离的皮肤成纤维细胞(Sfbs),颅骨,和皮肤,分别,进行了检查。用对照条件培养基(Cont-CDM)和PDL细胞培养条件培养基(PDL-CDM)培养成骨细胞长达21天。然后用碱性磷酸酶和vonKossa染色对培养的成骨细胞进行染色。通过实时定量PCR分析在每种条件培养基中培养的成骨细胞的骨Gla蛋白(Bgp),Axin2和Ki67表达。分析用于获得条件培养基的PDL细胞的Sost,ctodin和Wnt1的表达与Sfbs的表达比拟。
结果:免疫组化染色观察到牙周膜组织中硬化蛋白的表达。与成骨细胞培养中的Cont-CDM相比,PDL-CDM抑制了矿化结节的形成。在PDL-CDM中,与Cont-CDM相比,成骨细胞中Bgp和Axin2的表达水平降低。在PDL单元格中,Sost和Ectodin的表达水平远高于Sfbs;然而,Wnt1在PDL细胞中的表达低于Sfbs。
结论:PDL细胞分泌各种蛋白质,包括硬化蛋白,并通过经典的Wnt途径抑制成骨细胞的成骨。
OBJECTIVE: Recent reports indicate that sclerostin is secreted by periodontal ligament tissue-derived (PDL) cells during orthodontic force loading and that the secreted sclerostin contributes to bone metabolism. However, the detailed mechanism is poorly understood. The aim of this study was to determine how PDL cells affect bone formation.
METHODS: Rat periodontal ligament tissue was immunohistochemically stained for sclerostin. Cultured primary PDL cells,
osteoblasts, and skin fibroblasts (Sfbs) isolated from rat periodontal ligament tissue, calvaria, and skin, respectively, were examined.
Osteoblasts were cultured with control conditioned medium (Cont-CDM) and PDL cell culture conditioned medium (PDL-CDM) for up to 21 days. Cultured
osteoblasts were then stained with alkaline phosphatase and von Kossa stain.
Osteoblasts cultured in each conditioned medium were analyzed by real-time quantitative PCR for bone Gla protein (Bgp), Axin2, and Ki67 expression. PDL cells used to obtain conditioned medium were analyzed for Sost, Ectodin and Wnt1 expression and compared with expression in Sfbs.
RESULTS: Expression of sclerostin was observed in periodontal ligament tissue by immunohistochemical staining. The formation of mineralization nodules was inhibited in PDL-CDM compared with Cont-CDM in osteoblast culture. In PDL-CDM, the expression levels of Bgp and Axin2 in
osteoblasts were decreased compared with Cont-CDM. In PDL cells, expression levels of Sost and Ectodin were much higher than in Sfbs; however, expression of Wnt1 was lower in PDL cells compared with Sfbs.
CONCLUSIONS: PDL cells secrete various proteins, including sclerostin and suppress osteogenesis in osteoblasts through the canonical Wnt pathway.