中国血液净化

›› 2005, Vol. 4 ›› Issue (1): 5-9.

• 论著 • 上一篇    下一篇

T型钙通道α1G亚单位在慢性肾衰竭大鼠左心室心肌中的表达及钙三醇干预的研究

谭若芸 赵卫红 王笑云 刘翠萍   

  1. 210029 南京，南京医科大学第一临床医学院肾内科（谭若芸，赵卫红，王笑云）；内分泌科（刘翠萍）
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2005-01-12 发布日期:2005-01-12

  • Received:1900-01-01 Revised:1900-01-01 Online:2005-01-12 Published:2005-01-12

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摘要：

目的 观察慢性肾衰竭（CRF）大鼠左心室心肌中T型钙通道α1G亚单位的表达与心肌肥厚的关系，研究钙三醇对其表达的影响。方法 24只雄性清洁级SD大鼠随机分为三组，每组8只：① CRF组；②CRF加钙三醇组（50ng/d灌胃）；③假手术对照组。采用两步法5/6肾大部分切除（SNx）制备CRF动物模型；对照组施行假手术。术后12周处死大鼠，检测各组大鼠心重/体重比、血清尿素氮（BUN）、肌酐(Cr)和甲状旁腺素(iPTH)水平以及内生肌酐清除率（Ccr），并用逆转录聚合酶链反应（RT-PCR）两步法观察大鼠左心室心肌中T型钙通道α1G亚单位信使核糖核酸（mRNA）的表达。结果 与对照组相比，术后12周CRF组血清BUN、SCr、iPTH和心重/体重比值明显上升（ P<0.01）， CCr明显降低（P<0.01），且左心室心肌中重新出现 α1G 亚单位mRNA的表达（P≤0.001）；而钙三醇组，除血清 iPTH较CRF组明显下降外（P<0.01），其血清 BUN、SCr、CCr和心重/体重比值，以及左心室心肌中α1G亚单位mRNA的表达均与CRF组无明显差异（P>0.05）。结论 CRF大鼠心肌重量明显增加，左心室心肌出现T型钙通道的异常表达，提示T型钙通道可能在CRF心肌肥厚中起重要作用；但用钙三醇干预后虽iPTH能降低，但左心室心肌中T型钙通道α1G亚单位的表达无明显变化，提示钙三醇对心肌肥厚作用不明显，因此进一步研制针对T型钙通道的特异性阻滞剂是很有意义的。

关键词: T型钙通道, α1G亚单位mRNA, 慢性肾衰竭, 左心室心肌, 钙三醇

Abstract:

Objective To investigate the relation between myocardium hypertrophy and the expression of α1G subunit of T-type calcium channels in left ventricular myocytes of 5/6 SNx rats, and the effect of calcitriol on the expression of α1G subunit of T-type calcium channels. Methods Twenty-four male Sprague-dawley rats were randomly divided into three groups(n=8): A. CRF; B.CRF administrated 50ng/d of calcitriol; C: sham-operated control. Sprague-dawley rats in group A and B underwent two-step 5/6 subtotal nephrectomy(SNx)；control rats underwent bilateral renal decapsulation. After 12 weeks,all rats were sacrificed, and the ratio of heart weight and body weight, blood urea nitrogen (BUN),serum creatinine(SCr),intact parathyroid hormone(iPTH) and creatinine clearance(CCr) were detected. Moreover, the expression of α1G subunits mRNA of T-type calcium channels were detected by RT-PCR. Results Compared to group C, the ratio of heart weight and body weight, BUN, SCr, iPTH in group A were obviously elevated (P<0.01) and CCr were significantly decreased (P<0.01); α1G subunits mRNA of T-type calcium channels were expressed again in the left ventricular myocytes of 5/6 SNx rats( P≤0.001). In group B, compared to group A, in addition to iPTH witch was predominantly decreased, the ratio of heart weight and body weight, Bun, SCr, CCr and the expression of α1G subunits mRNA were not obviously changed (P>0.05). Conclusion There are increase of heart weight and expression of T-type calcium channels in left ventricular myocytes of 5/6 SNx rats. It implies that T-type calcium channel may play an important role in myocardium hypertrophy of 5/6 SNx rats. In 12 weeks after 5/6 SNx, there were no obvious change of α1G subunits mRNA. It indicates the research on finding new-type specificic blocker of T-type calcium channel is very necessary. 

Key words: α1Gsubunit mRNA, Chronic renal failure, Left ventricular myocytes, Calcitriol

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