中文摘要：

背景：将磁性纳米颗粒作为骨组织工程领域新兴材料并植入生物体时,其毒性机制基础研究及安全性评价就显得格外重要。目的：探索磁性四氧化三铁纳米颗粒作用于前成骨细胞的生物相容性。方法：将含有0,200,400,800 mg/L磁性四氧化三铁纳米颗粒的细胞培养液作用于小鼠前成骨细胞24 h后,采用碱性磷酸酶活性测试试剂盒、骨钙素酶联免疫试剂盒、CCK-8试剂盒、倒置显微镜、细胞骨架荧光染色法及实时荧光定量PCR,观察处理后小鼠前成骨细胞的碱性磷酸酶活性/总蛋白比值、骨钙素浓度、细胞增殖率、细胞形态和骨架改变、细胞凋亡以及自噬相关半胱氨酸蛋白酶3、LC3A、LC3B基因m RNA表达情况。结果与结论：（1）磁性四氧化三铁纳米颗粒作用小鼠前成骨细胞24 h后,200 mg/L组与对照组（0 mg/L）相比,各项指标差异无显著性意义;（2）作用24 h后,400,800 mg/L组细胞内碱性磷酸酶活性/总蛋白比值、骨钙素浓度上升,细胞增殖率明显下降,细胞形态及骨架结构改变明显,LC3B基因转录水平升高,而半胱氨酸蛋白酶3、LC3A基因转录水平与对照组相比差异无显著性意义;（3）结果提示,高质量浓度的磁性四氧化三铁纳米颗粒作用于小鼠前成骨细胞24 h后,虽具有一定的促成骨作用,但同时可造成细胞毒性损伤,促进细胞自噬相关基因LC3B表达上调,影响细胞形态、骨架结构及细胞增殖率。

英文摘要：

BACKGROUND： Investigations on toxic mechanism and safety of magnetic ferrosoferric oxide（Fe3O4） nanoparticles are extremely necessary when these nanoparticles as an emerging material for bone tissue engineering are implanted into the living body. OBJECTIVE： To investigate the biocompatibility of magnetic Fe3O4 nanoparticles with preosteoblasts. METHODS： Mouse preosteoblasts were cultured in 0, 200, 400, 800 mg/L magnetic Fe3O4 nanoparticles. After 24 hours, alkaline phosphatase activity, osteocalcin level, cell proliferation rate, cellular morphology, cytoskeleton variation, cell apoptosis and autophagy-related genes, such as Caspase-3, LC3 A, LC3 B, were detected by alkaline phosphatase assay kit, ELISA kit, cell counting kit-8 kit, inverted microscope, laser confocal microscopy and real-time PCR, respectively. RESULTS AND CONCLUSION： After 24 hours of culture, there ware no significant differences between 200 mg/L group and control group. However, in the groups of 400 and 800 mg/L, the ratio of alkaline phosphatase activity to total protein and osteocalcin level increased, the cell proliferation rate decreased, cellular morphology and cytoskeleton changed remarkably, LC3 B expression was up-regulated compared with the control group. Additionally, there were also no significant differences in the expression of Caspase-3 and LC3 A between 400 and 800 mg/L groups and control group. Therefore, magnetic Fe3O4 nanoparticles at high level contributes to cytotoxicity and up-regulation of LC3 B expression, and affects cellular morphology, cytoskeleton and cell proliferation rate, although these nanoparticles can increase the osteoblastic differentiation.