eEF1A2敲除对小鼠骨骼肌组成的影响

The Composition Changes of Skeletal Muscle in eEF1A2 Knockout Mice

目的 探究真核细胞翻译延长因子1-α2 (eEF1A2)缺失对小鼠骨骼肌的含量和组成的改变。方法 12月龄的eef1a2;CreER小鼠(iHBKO)及其对照eef1a2;CreER小鼠(Control)分别连续3 d腹腔注射30 mg/kg他莫昔芬,利用实时荧光定量PCR(qRT-PCR)和Western Blot验证小鼠骨骼肌eEF1A2敲除效率,利用HE染色检测小鼠骨骼肌形态,qRT-PCR检测小鼠骨骼肌主要纤维类型标志物的表达变化。结果 与对照组小鼠相比,iHBKO小鼠骨骼肌实现了eEF1A2的高效敲除。敲除小鼠腓肠肌脏器系数下降,但腓肠肌形态及横截面积无明显变化。eEF1A2基因敲除还导致快肌腓肠肌和趾长伸肌中慢肌标志物肌球蛋白重链7(myosin heavy chain 7,Myh7)表达明显升高,快肌标志物肌球蛋白重链4(myosin heavy chain 4,Myh4)明显降低,而慢肌比目鱼肌和胫骨前肌的Myh4和Myh7显著降低。结论 eEF1A2缺失降低了腓肠肌脏器系数,并导致小鼠快肌纤维向慢肌纤维的转化。

Objective To investigate the effects of eEF1A2 deletion on contents and composition in mice skeletal muscle.Method Twelve-month-old eef1a2;CreERmice(iHBKO) and their control eef1a2;CreERmice(Control) were intraperitoneally injected with 30 mg/kg tamoxifen for three consecutive days, respectively, and the efficiency of eEF1A2 knockout in skeletal muscle was verified using real-time qPCR and Western blot, the skeletal muscle morphology was detected by HE staining, and the expression of the fiber type markers were measured by real-time qPCR.Result eEF1A2 was knocked out in skeletal muscle in iHBKO mice. The gastrocnemius muscle organ coefficient decreased significantly in knockout mice. However, the organ coefficients in other skeletal muscle and the gastrocnemius muscle morphology did not alter. eEF1A2 knockout also resulted in a significant increase of the slow muscle marker myosin heavy chain 7(Myh7) expression and a significant decrease of the fast muscle marker myosin heavy chain 4(Myh4) expression in the gastrocnemius and extensor digitorum longus muscle, while Myh4 and Myh7 both decreased in the slow muscle soleus and tibialis anterior muscle.Conclusion eEF1A2 deletion reduced the gastrocnemius composition, and converted fast to slow muscle fibers in mice.