目的 力学载荷作用下，骨细胞通过分泌因子来影响骨代谢和骨形成，本研究旨在筛选骨细胞分泌因子相关力学响应微小RNA(microRNA, miRNA)。方法 分别向体外培养骨细胞和成骨细胞施加2500 με、0.5 Hz的周期性张应变，采用miRNA芯片，筛选出仅在骨细胞中差异表达的miRNA，通过生物信息学技术，从这些miRNA中进一步筛选出靶基因为胰岛素样生长因子1、NO合成酶、成纤维细胞生长因子23和硬骨素等分泌因子的miRNA，与小鼠跑台锻炼后芯片检测出的小鼠股骨组织差异表达miRNA进行比较，然后随机选4个miRNA进行定量PCR验证。结果 仅在体外经力学刺激的骨细胞中差异表达的77个miRNA中，筛选出22个靶基因为以上4种分泌因子的miRNA，并进一步筛选出11个在跑台锻炼后的小鼠骨组织中以同样趋势差异表达的miRNA，其中随机选出的miR-361-3p、miR-3082-5p、miR-6348和miR-706，也在骨细胞和骨组织中以同样趋势同样差异表达。结论 本研究表明，这些仅在骨细胞中差异表达的力学响应微小RNA，很可能通过调节分泌因子影响成骨分化或骨代谢。
Objective Stimulated by mechanical loading, osteocytes influence bone metabolism and bone formation through their secretory factor, so that this study aimed to select secretory factor-related, mechanoresponsive microRNA (miRNA) of osteocytes. Methods After mechanical tensile strain of 2500 microstrain (με) at 0.5 Hz was applied to osteocytes and osteoblasts cultured in vitro respectively, using miRNA chip, the differentially expressed miRNAs only in the osteocytes were screened out. Through bioinformatics technology, in these differentially expressed miRNAs, the target genes of which were secretory factors including insulin-like growth factor-1(IGF-1), nitric oxide synthesase (NOS), fibroblast growth factor 23 (FGF23) and sclerostin (SOST) were further selected. Then the selected miRNAs were compared with the biochip detected, differentially expressed miRNAs in femur bone of mice which were trained on treadmill and four of these miRNAs were randomly selected for quantitative PCR verification. Results In the 77 differentially expressed miRNAs only in the mechanically strained osteocytes in vitro, 22 miRNAs whose target genes are the 4 secreted factors mentioned above , were screened out. Moreover, 11 in the 22 miRNAs were differentially expressed in femur bone of the treadmill trained mice at the same trend as in osteocytes in vitro, and the randomly choiced miR-361-3p, miR-3082-5p, miR-6348 and miR-706 were confirmed to be differentially expressed at the same trend in femur bone and osteocytes. Conclusions The study indicated that these mechanoresponsive miRNAs differentially expressed only in osteocytes, probably influence osteoblastic differentiation or bone metabolism through regulating secretory factors.