Li Z B, Gao Y Q, Tang Z S
Institute of Sports Medicine, Beijing Medical University, Beijing 100083.
Sheng Li Xue Bao. 1998 Oct;50(5):551-6.
Our previous studies have shown that the myocardial phenotypes between exercise-induced and hypertensive cardiac hypertrophy are different. However, alteration of cardiac gene expression in the two kinds of hypertrophy is not clear. We therefore studied the expression of immediate early and late responsive gene in Wistar rats subject to a 12-weeks swimming program and spontaneously hypertensive rats (SHR) by Northern blot. The autoradiographs were analyzed by scanning densitometry. When compared with matched sedentary control, swimming rats and SHR increased their heart/body weight by 29% and 61% respectively (P < 0.01). After a series of swimming program, levels of c-fos and atrial natriuretic factor (ANF) mRNA were instantly increased 203% and 214% respectively in the swimming rats. However in 24 h after swimming, ANF mRNA was decreased to the level of control but c-fos mRNA was still higher than than in control. The levels of c-fos and ANF mRNA were increased by 80% and 298% in SHR respectively. The expression of beta-myosin heavy chain (MHC) mRNA was increased by 117% in SHR but decreased by 12% in swimming rats. The expression of alpha-MHC mRNA was decreased by 42% in SHR but unchanged in swimming rats. The abundance alpha/beta-MHC mRNA in swimming rats is 336% higher than in SHR. These results showed differential expression of the immediate early and late responsive gene in exercise-induced and SHR hypertrophied heart remodeling. It is suggested that (1) the differential expression of c-fos gene may differently regulate remodeling of these two cardiac hypertrophies; (2) the differential expression of ANF gene may be a molecular marker for distinguishing the two kinds of cardiac hypertrophy; and (3) the differential expression of alpha/beta-MHC gene ratio may regulate exercise-induced and hypertensive hypertrophied myocardial cell changing to contractile phenotype and synthetic phenotype respectively, at the gene transcription level.
我们之前的研究表明，运动诱导的心脏肥大和高血压性心脏肥大的心肌表型有所不同。然而，两种肥大状态下心脏基因表达的变化尚不清楚。因此，我们通过Northern印迹法研究了经12周游泳训练的Wistar大鼠和自发性高血压大鼠（SHR）中早期即刻反应基因和晚期反应基因的表达。通过扫描密度计对放射自显影片进行分析。与相匹配的久坐不动的对照组相比，游泳大鼠和SHR的心脏/体重分别增加了29%和61%（P<0.01）。经过一系列游泳训练后，游泳大鼠中c-fos和心钠素（ANF）mRNA水平立即分别增加了203%和214%。然而，游泳后24小时，ANF mRNA降至对照水平，但c-fos mRNA仍高于对照。SHR中c-fos和ANF mRNA水平分别增加了80%和298%。β-肌球蛋白重链（MHC）mRNA的表达在SHR中增加了117%，但在游泳大鼠中下降了12%。α-MHC mRNA的表达在SHR中下降了42%，但在游泳大鼠中未发生变化。游泳大鼠中α/β-MHC mRNA的丰度比SHR高336%。这些结果表明，早期即刻反应基因和晚期反应基因在运动诱导的和SHR肥大心脏重塑中存在差异表达。提示：（1）c-fos基因的差异表达可能对这两种心脏肥大的重塑有不同的调节作用；（2）ANF基因的差异表达可能是区分两种心脏肥大的分子标志物；（3）α/β-MHC基因比例的差异表达可能在基因转录水平上分别调节运动诱导的和高血压性肥大心肌细胞向收缩表型和合成表型的转变。
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