热休克蛋白70对骨骼肌细胞纤维类型分化的影响

目的：探讨高表达热休克蛋白70（heat shock protein 70，Hsp70）对骨骼肌细胞（C2C12细胞）纤维类型分化的影响。方法：通过构建重组pTRE2 hyg-Hsp70质粒稳定转染C2 C12细胞系，建立Hsp70高表达的C2C12细胞系。经过诱导分化形成骨骼肌纤维，观察不同时间点（0、3、7 d）C2C12细胞的分化情况，并检测骨骼肌类型标志肌球蛋白重链（ myosin heavy chain ，MHC）的表达情况。结果：与对照组相比，高表达Hsp70的C2C12细胞系分化后的3、7 d，MHCⅠmRNA及蛋白的表达明显增高（P＜0．05），而在分化后7 d，MHCⅡb mRNA及蛋白的表达明显下降（ P＜0．05）。结论：高表达Hsp70的骨骼肌细胞C2 C12可以诱导MHCⅠ的表达，促进骨骼肌细胞向Ⅰ型肌纤维转化。

Effect of over-expression Hsp70 on the skeletal muscle fiber transformation in C2C12 cells

Objective： To examine the effect of over-expression heat shock protein （ Hsp ） 70 on the skeletal muscle fiber transformation in C2C12 cells.Methods：Hsp70 gene was amplified from pAT153 plasmids and then cloned into pTRE2hyg vector.After the transfection of recombinant plasmids of pTRE 2hyg-Hsp70 into the C2C12 cells,the expression of Hsp70 was examined by Western blot .Furthermore,the expression of myosin heavy chain （MHC） in over-expression Hsp70 C2C12 cells was evaluated by real-time PCR and Western blot at different time points（0,3,7 d） after the differentiation of C2C12 cells.Results：Compared with controls,the mRNA and protein expression of MHCⅠwas significantly increased（P〈0.05）at different time points（3,7 d） after differentiation, whereas the expression of MHCⅡb was decreased（P〈0.05）at 7 d after differentiation.Conclusion：The C2C12 cells of over-expression Hsp70 can induce the enhancement of MHCⅠexpression and facilitate the transformation of type Ⅰfiber from C2C12 cells.