后肢尾吊对大鼠比目鱼肌MicroRNA表达的影响

Effects of Tail-suspension on MicroRNA Expression in Rats Soleus

目的研究后肢尾吊模拟失重效应对大鼠比目鱼肌microRNA(miRNA)表达的影响,为失重性肌萎缩发生发展机制提供实验证据。方法 60只SD大鼠,随机分为尾吊组和对照组,分别在尾吊第7天、14天、28天分离SD大鼠比目鱼肌,提取miRNA和总RNA,进行miRNA表达谱分析,并运用生物信息学和Real-time PCR方法验证相关miRNA及其靶基因变化结果。结果后肢尾吊导致比目鱼肌显著萎缩,质量下降。表达谱分析显示尾吊7 d和14 d差异表达miRNA分别有18和13个;PCR结果显示促进肌分化的miR-214持续下调,最高达42%(P<0.05),促肌再生miR-206无显著变化。抑制蛋白降解的miR-486-5p在尾吊初期下调,而抑制IGF-1的miR-320家族在后期下调,均超过50%,并具有显著性差异。共同靶基因whyz表达上调与多数miRNA下调的结果一致。结论 miR-214、miR-486-5p和miR-320在模拟失重诱导肌萎缩过程中表达显著改变。

Objective The effect of tail-suspension （TS） on microRNA （ miRNA）- expression in rats soleus was studied in order to provide the evidence of muscle dystrophy mechanism induced by microgravity. Methods Sixty SD rats were randomly derided into 2 groups, tail suspension （TS） and control（Con）. Total RNA was ex- tracted from soleus of SD rats exposed to tail suspension for 7 days, 14 days and 28 days. miRNAs expressions were determined by microRNA array and analyzed by bioinformation. Some significantly changed miRNA and their predicted target genes were confirmed by real-time polymerase chain reaction. Results Compared with control, relative muscle weight in TS decreased remarkably, miR-214 which can promote myoblats differentia- tion persistently decreased during TS. Regenerative miR-206 expression almost unchanged, miR-486-5p which inhibited protein degradation decreased 50% （P 〈 0.01 ） in TS-7, but held in TS-14 and TS-28. Moreover, miR-320 and miR-320b which targeted IGF-1 decreased 39% （P 〈0.01 ） and 55% （P 〈0.01 ） respectively in TS-28. Consistent to miRNAs decrease, predicted target mRNAs increased such as whyz and sfrp in TS group. Conclusion miR-214, miR-486 and miR-320 changed significantly during TS which may be related to muscle dystrophy induced by microgravity.