中文摘要：

目的 探讨机械应力加载是否干扰体外培养C2C12成肌细胞自身抗原及TLR3的转录表达。方法 对生长于BioFlex柔性基底膜表面的C2C12细胞施加不同频率的拉伸加载，流式细胞术分析细胞增殖情况。Real-time RT-PCR检测并比较分析应力加载前、后骨骼肌自身抗原（HRS、Mi-2、U1-70、DNA-PKcs）、TLR3的mRNAs表达差异。结果 0.25 Hz、10%幅度、2 h/d的拉伸条件能加速C2C12细胞进入细胞周期。 2 d和4 d拉伸组DPI较对照组提高（P＜0.05），尤以2d拉伸组细胞增殖最为显著。拉伸2 d时，C2C12细胞内HRS、 Mi-2、U1-70、DNA-PKcs以及TLR3的mRNA水平均显著低于同一培养时间的对照组（P＜0.05）。结论 机械应力刺激信号可能参与下调与骨骼肌组织炎症相关的免疫调节分子。

英文摘要：

Objective To investigate the effect of mechanical-stretch on the expression of myositis autoantigens and proinflammatory TLR3 in cultured C2C12 myoblasts. Methods C2C12 cells cultured on the surface of BioFlex flexible basement membrane in vitro were subjected to cyclic strain. The proliferation of C2C12 cells was detected usingflow cytometry. The mRNA expression of myositis autoantigens （HRS, Mi-2, DNA-PKcs, U1-70） and TLR3 were analyzed through Real-time RT-PCR. Results Cyclic echanical-stretch about 2d stimulated C2C12 cell cycling and early down-regulation of mRNA levels of TLR3 and Mi-2, HRS, DNA-PKcs and U1-70 under the strain of 10% lengthening, 0.25Hz frequencyfor 2h per day（P〈0.05）. Conclusions Mechanical stretch reduces expression of muscle autoantigens and of pro-inflammatory TLR3, which may provide new insight to understand howresistance exercise reduce the symptoms associated with myositis.