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背景:骨质疏松涉及破骨细胞分化成熟和成骨类细胞凋亡两方面,肿瘤坏死因子α能诱导多种细胞凋亡且效率差异很大,骨保护素能抑制破骨细胞成熟,但对成骨类细胞凋亡的作用未见报道。目的:探讨肿瘤坏死因子α能否诱导成骨类细胞凋亡及骨保护素能否抑制其凋亡。设计:以成骨细胞和MG63细胞作为实验对象、以鼠WEHI164细胞系用于阳性对照的观察对比分析。单位:解放军总医院全军口腔医学研究所、美国匹茨堡医学院退伍军人医疗中心。材料:本实验于2001-01/2003-12在Dr.Blair实验室和口腔研究所实验室完成。选择商品化细胞系,RPMI1640培养液和各种相关蛋白用于实验。方法:用人间充质干细胞在分化培养液中培养21d使之成为成骨细胞,与MG63一起用于凋亡实验。AnnexinV和原位末端标记法检测肿瘤坏死因子α诱导成骨类细胞凋亡。主要观察指标:全部细胞数及凋亡细胞数。结果:和FasL诱导细胞凋亡一样,肿瘤坏死因子α能引起MG63骨肉瘤细胞,间充质干细胞和成骨细胞的凋亡,并表现为明显的浓度依赖和时间依赖。低浓度肿瘤坏死因子α(170～500pmol/L)作用于细胞2～4h就显示了较明显的凋亡,而骨保护素在0.45～1.5nmol/L浓度时,几乎完全抑制了500pmol/L肿瘤坏死因子α诱导的凋亡。成骨细胞分泌骨保护素,而破骨细胞及破骨前体细胞产生肿瘤坏死因子α,它们相互作用降低成骨细胞的凋亡。结论:肿瘤坏死因子α能诱导成骨类细胞凋亡,骨保护素能够抑制肿瘤坏死因子α的凋亡诱导作用,从抑制破骨细胞成熟和成骨细胞凋亡两方面表现骨保护素防治骨质疏松的作用机制。
BACKGROUND: Osteoporosis involves both osteoclast differentiation and osteoblast apoptosis. Tumor necrosis factor-α (TNF-α) induces apoptosis in a variety of cell types and varies widely in potency. Osteoprotegerin inhibits osteoclast maturation but The role of osteoblast apoptosis has not been reported. Objective: To investigate whether tumor necrosis factor α can induce osteoblast apoptosis and whether osteoprotegerin can inhibit apoptosis. DESIGN: Osteoblasts and MG63 cells were used as experimental subjects and the control group of WEHI164 cells was used as a positive control for comparative analysis. Unit: General Hospital of PLA PLA Stomatological Institute, Medical School of Pittsburgh Veterans Medical Center. Materials: The experiment was performed in the laboratory of Dr. Blair and Dental Institute from January 2001 to December 2003. Commercially available cell lines, RPMI1640 medium and various related proteins were selected for experiments. METHODS: Human bone marrow mesenchymal stem cells were cultured in differentiation medium for 21 days to become osteoblasts and used with MG63 in apoptosis experiment. AnnexinV and orthotopic end labeling were used to detect the apoptosis of osteoblast induced by tumor necrosis factor. MAIN OUTCOME MEASURES: Total number of cells and number of apoptotic cells. RESULTS: Tumor necrosis factor-alpha, like FasL-induced apoptosis, caused apoptosis in MG63 osteosarcoma cells, mesenchymal stem cells and osteoblasts, and showed a significant concentration-dependent and time-dependent manner. Low concentration of tumor necrosis factor alpha (170 ~ 500pmol / L) in the cells 2 ~ 4h showed a more obvious apoptosis, and osteoprotegerin at 0.45 ~ 1.5nmol / L concentration, almost completely inhibited 500pmol / L tumor Necrosis factor alpha-induced apoptosis. Osteoblasts secrete osteoprotegerin, whereas osteoclasts and osteoclast precursors produce tumor necrosis factor-α, and their interaction decreases osteoblast apoptosis. CONCLUSION: Tumor necrosis factor alpha can induce apoptosis of osteoblast. Osteoprotegerin can inhibit the induction of apoptosis of tumor necrosis factor alpha. It can prevent and treat osteoporosis by inhibiting the osteoclast maturation and osteoblast apoptosis The loose mechanism of action.