血管钠肽对低氧大鼠心脏钠尿肽C受体表达的影响

EFFECT OF VASONATRIN PEPTIDE ON THE EXPRESSION OF C-TYPE NATRIURETIC PEPTIDE RECEPTOR IN HYPOXIC RAT HEARTS

目的 :探讨低氧对大鼠心脏钠尿肽C受体 (NPR C)表达的调节作用 ,以及血管钠肽 (VNP)对这一过程的影响。方法 :将大鼠随机分为 3组 :对照组、低氧组 (3～ 2 8d)和VNP(2 5～ 75 μg/kgbw) +低氧组 ,采用放射免疫的方法测定大鼠血浆心房钠尿肽 (ANP)的浓度 ,并采用定量PCR的方法分析NPR C的mRNA水平。结果 :低氧 2 8d大鼠血浆ANP浓度显著高于正常大鼠 (P <0 .0 5 ) ,而且每天注射 75 μg/kgbw的VNP使ANP浓度进一步升高 (P <0 .0 1)。低氧 3d对大鼠心脏NPR C的mRNA的量没有显著影响 ;低氧 7d使大鼠心脏NPR C的mRNA的拷贝数显著升高 (P <0 .0 5 ) ;低氧 14d、2 8d使大鼠心脏NPR C的mRNA的拷贝数进一步升高 (P <0 .0 1)。每日注射 2 5μg/kgbw的VNP对低氧诱导的大鼠心脏NPR C表达没有显著影响 ;5 0 μg/kgbw的VNP显著降低低氧大鼠心脏NPR C的表达 (P <0 .0 5 ) ;75 μg/kgbw的VNP进一步降低低氧大鼠心脏NPR C的表达 (P <0 .0 1)。 结论 :VNP可以升高低氧大鼠的血浆ANP水平 ;低氧可以使大鼠心脏NPR C表达增加 ,而且具有时间依赖性 ,而VNP对这一过程有抑制作用 。

Aim: To investigate the effect of vasonatrin peptide (VNP) on the expression of C type natriuretic peptide receptor (NPR C) in hypoxic rat hearts. Methods: Rats were divided randomly into three groups:control group,hypoxia group(3～28 d) and VNP(25～75 μg/kg per day) + hypoxia group. The plasma concentration of atrial natriuretic peptide (ANP) in rats was measured by the means of radioimmunoassay.Furthermore,quantitative PCR was used to examine the NPR C mRNA level in rat hearts. Results: The plasma concentration ANP in rats was significantly higher than that of control group ,and VNP (75 μg/kg per day) made it more higher. Hypoxia for 3 day of had no significant effect on the NPR C mRNA level in rat hearts, while hypoxia for 7～28 d significantly increased the level of NPR C mRNA in a time dependent manner. VNP (50～75 μg/kg per day) significantly reduced the NPR C mRNA level in rat hearts in a dose dependent manner. Concluson: VNP increases the plasma concentration of ANP in hypoxic rats. Hypoxia can increase expression of NPR C in rat hearts significantly, which can be inhibited by VNP.