Wang Yun-ying, Yu Zhi-bin, Xie Man-jiang, Feng Han-zhong, Gao Fang
Space Med Med Eng (Beijing). 2002 Aug;15(4):260-4.
Objective. To make an Achilles tenotomy rat model to observe the change in soleus weight and expression of myosin heavy chain (MHC) isoform mRNA, and to find some clues for elucidating the mechanisms of soleus disuse. Method. Thirty male Sprague-Dawley [correction of Sprangue] rats were divided into 6 groups. On the lst, 3rd, 7th, 14th, 21st and 28th days after Achilles tenotomy, wet weight of soleus (SOL), plantaris (PL), gastrocnemius mediales (MG), and gastrocnemius lateral (LG) muscles were measured. Expression of MHC IIx mRNA was observed by means of reverse transcriptase-polymerase chain reaction (RT-PCR). Result. Wet weight of SOL, MG, LG, and PL decreased significantly on the 3rd day after the tenotomy. The wet weight of these muscles reduced to the minimum on the 7th or 14th days after the tenotomy, and then recovered slightly on the 21st day after the tenotomy. There was only the expression of MHC I and MHC IIa mRNA in normal soleus muscle, but no MHC IIx or MHC IIb mRNA. The expression of MHC IIx mRNA occurred in SOL on the 3rd day after tenotomy and still expressed on the 28th day after tenotomy. There was no expression of MHC IIb mRNA in SOL after Achilles tenotomy. Conclusion. The appearance of atrophy of rat soleus induced by Achilles tenotomy is similar in time and extent with that induced by tail-suspension. The expression of MHC IIx mRNA is shown in rat soleus muscles in Achilles tenotomy and tail-suspension models. The study suggests that expression of MHC IIx mRNA may be used as a molecular marker of soleus muscle disuse in rats.
目的。制作跟腱切断大鼠模型，观察比目鱼肌重量变化及肌球蛋白重链（MHC）亚型mRNA的表达，为阐明比目鱼肌废用机制寻找线索。方法。将30只雄性Sprague-Dawley大鼠分为6组。在跟腱切断术后第1、3、7、14、21和28天，测量比目鱼肌（SOL）、跖肌（PL）、内侧腓肠肌（MG）和外侧腓肠肌（LG）的湿重。通过逆转录聚合酶链反应（RT-PCR）观察MHC IIx mRNA的表达。结果。跟腱切断术后第3天，SOL、MG、LG和PL的湿重显著下降。这些肌肉的湿重在跟腱切断术后第7天或第14天降至最低，然后在跟腱切断术后第21天略有恢复。正常比目鱼肌中仅存在MHC I和MHC IIa mRNA的表达，而不存在MHC IIx或MHC IIb mRNA。跟腱切断术后第3天，SOL中出现MHC IIx mRNA的表达，且在跟腱切断术后第28天仍有表达。跟腱切断术后，SOL中未出现MHC IIb mRNA的表达。结论。跟腱切断诱导的大鼠比目鱼肌萎缩在时间和程度上与尾部悬吊诱导的相似。在跟腱切断和尾部悬吊模型的大鼠比目鱼肌中均出现MHC IIx mRNA的表达。该研究表明，MHC IIx mRNA的表达可能作为大鼠比目鱼肌废用的分子标志物。
