T型钙通道α_(1G)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  

The expression of α_( 1G) subunit of T-type calcium channels in left ventricular myocytes of 5/6 SNx rats and the effect of Calcitriol on it

作　　者：谭若芸[1] 赵卫红[1] 王笑云[1] 刘翠萍[2] 

机构地区：[1]南京医科大学第一临床医学院肾内科,南京210029 [2]南京医科大学第一临床医学院内分泌科,南京210029

出　　处：《中国血液净化》2005年第1期5-9,共5页Chinese Journal of Blood Purification

基　　金：20 0 1年江苏省普通高等学校"青蓝工程"启动基金资助项目 (2 0 0 1- 0 9)

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　 2 4只雄性清洁级SD大鼠随机分为三组 ,每组 8只 :①CRF组 ;②CRF加钙三醇组 (5 0ng/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 .0 1) ,CCr明显降低 (P <0 .0 1) ,且左心室心肌中重新出现α1G亚单位mRNA的表达 (P≤ 0 .0 0 1) ;而钙三醇组 ,除血清iPTH较CRF组明显下降外 (P <0 .0 1) ,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 .0 5 )。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 。Objective To investigate the relation between myoca rdium hypertrophy and the expression of α 1G subunit of T-type calcium cha nnels in left ventricular myocytes of 5/6 SNx rats, and the effect of calcitriol on the expression of α 1G subunit of T-type calcium channels. Methods Twenty-four male Sprague-dawley rats were randomly divid ed 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 decapsulati on. After 12 weeks,all rats were sacrificed, and the ratio of heart weigh t and body weight, blood urea nitrogen (BUN),serum creatinine(SCr),intact parath yroid hormone(iPTH) and creatinine clearance(CCr) were detected. Moreover, the e xpression of α 1G subunits mRNA of T-type calcium channels were detected b y 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 signif icantly decreased (P<0.01); α 1G subunits mRNA of T-type c alcium 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, Bu n, SCr, CCr and the expression of α 1G subunits mRNA were not obviously ch anged (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 implie s that T-type calcium channel may play an important role in myocardium hypertrop hy of 5/6 SNx rats. In 12 weeks after 5/6 SNx, there were no obvious change of α 1G subunits mRNA. It indicates the research on finding new-type specifi cic blocker of T-type calcium channel is very necessary.

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 

分 类 号：R692.5[医药卫生—泌尿科学]