神经肽P物质及骨形态发生蛋白信号通路在ST2细胞成骨分化过程中的作用

目的 探讨神经肽P物质（SP）在ST2细胞（小鼠骨髓间充质干细胞）成骨分化过程中的作用及机制,以期为颞下颌关节骨关节炎的治疗提供依据。方法 对第3代ST2细胞分别用0、10^-10、10^-8 、10^-6、10^-5 mol·L^-1 SP培养,24、48、72 h后采用CCK-8实验检测细胞增殖情况。以10^-6 mol·L^-1 SP培养第3代ST2细胞1、3、5、7 d后,采用酶联免疫吸附试验（ELISA）检测上清液中碱性磷酸酶（ALP）、Ⅰ型胶原蛋白（CollaⅠ）和骨钙素（OCN）的表达,免疫荧光染色检测细胞ALP活性。分别用SP、Noggin（骨形态发生蛋白信号通路抑制剂）、SP+Noggin和2%胎牛血清培养ST2细胞,采用ELISA法检测上清液中ALP、CollaⅠ和OCN的表达。结果 CCK-8结果显示,24、48、72 h时均以10^-6 mol·L^-1 SP促进ST2细胞增殖活性最为明显（P<0.01）。ELISA结果显示,ALP表达在5 d时较对照组差异最为明显（P<0.01）,CollaⅠ和OCN的表达在7 d时较对照组差异最为明显（P<0.05）;免疫荧光结果显示,ALP活性在5 d时最强;加入抑制剂Noggin后,ALP、CollaⅠ和OCN表达量均降低。结论 SP可促进ST2细胞增殖和成骨分化,骨形态发生蛋白信号通路可能参与了此过程。

Role of neuropeptide substance P and the bone morphogenetic protein signaling pathway in osteogenic differentiation of ST2 cells

Objective This study aimed to investigate the role and mechanism of neuropeptide substance P (SP) in ST2 cell (bone mesenchymal stem cells of mice) osteogenic differentiation to provide a basis for the treatment of temporomandibular joint osteoarthritis. Methods Third-generation ST2 cells were cultured with different concentrations of SP (0, 10^-10, 10^-8, 10^-6, and 10^-5 mol·L^-1). After 24, 48, and 72 h, cell proliferation was detected by CCK-8. The ST2 cells were cultured with 10^-6 mol·L^-1 SP for 1, 3, 5, and 7 days. Subsequently, the expression of alkaline phosphatase (ALP), collagen typeⅠ(CollaⅠ), and osteocalcin (OCN) in the culture supernatant was tested by enzyme-linked immunosorbent assay (ELISA). ALP activity was detected by immunofluorescence staining. The ST2 cells were cultured with SP, Noggin (inhibitor of the bone morphogenetic protein signaling pathway), SP+Noggin, and 2% fetal bovine serum, respectively. Finally, the expression of ALP, CollaⅠ, and OCN in the culture supernatant was tested by ELISA. Results CCK-8 showed that the effect of cell proli-feration was most obvious when the SP concentration was 10^-6 mol·L^-1 (P<0.01). The ELISA results demonstrated that ALP expression significantly increased at day 5 compared with that in the control group (P<0.01), whereas the expression of CollaⅠand OCN significantly increased at day 7 (P<0.05). Immunofluorescence results showed that ALP activity was strongest at day 5. The expression of ALP, CollaⅠ, and OCN decreased after Noggin addition (P<0.05). Conclusion SP can promote the proliferation and osteogenic differentiation of ST2 cells, and the bone morphogenetic protein signaling pathway may be involved in this process.