血管紧张素Ⅱ对有高血压家族史人脐动脉血管平滑肌细胞离子泵的影响

Effects of Angiotensin Ⅱ on Ion Pumps of Smooth Muscle Cells Derived from Umbilical Artery of Human Neonates with Hypertensive Family History

背景细胞膜离子泵活性和血管紧张素Ⅱ(AngⅡ)异常在高血压发病过程中起重要作用。有高血压家族史(FH+)的青少年红细胞膜钠泵和钙泵活性比无高血压家族史(FH-)的对照组低,而在有高血压家族史的人动脉平滑肌细胞,离子泵活性变化以及AngⅡ干预对其的影响尚不清楚。目的探讨有无高血压家族史人脐动脉血管平滑肌细胞(HUASMCs)钠泵、钙泵活性及其mRNA表达的异同以及AngⅡ干预对上述指标的影响。方法选取有无高血压家族史新生儿脐带各7根,用组织块贴壁法培养其脐动脉平滑肌细胞,设置AngⅡ空白对照组和高、低两个剂量组,采用生化酶学方法和逆转录聚合酶链反应技术分别测量其细胞膜钠泵(Na+,K+-ATP酶)、钙泵(Ca2+-ATP酶)活性和mRNA相对表达量。结果未用AngⅡ时,FH+组HUASMCs质膜钠泵、钙泵活性均高于FH-组(均P<0.05),但其质膜钠泵α1亚单位mRNA表达和质膜Ca2+-ATP酶(PMCA)亚型1(PMCA1)mRNA表达无差异。AngⅡ干预后,在FH-组,AngⅡ(1×10-7mol/L)能提高两种离子泵活性(均P<0.01)和上调钠泵α1亚单位mRNA表达水平(P<0.01),AngⅡ(1×10-6mol/L)能抑制两种离子泵活性和下调钠泵mRNA表达水平(均P<0.01);在FH+组,AngⅡ(1×10-7mol/L)能抑制两种离子泵活性(均P<0.01)和下调其mRNA表达(P<0.05),AngⅡ(1×10-6mol/L)对两种离子泵活性的抑制更为明显(均P<0.01),但对Na+,K+-ATP酶α1亚单位和PMCA1的mRNA的相对表达量无影响。结论FH+的HUASMCs质膜钠泵和钙泵活性增高;AngⅡ抑制FH+的HUASMCs离子泵活性。

Background Ion pump activity in cells membrane plays an important role in hypertension pathogenesis.Erythrocyte membrane Na＋-K＋-ATPase and Ca2＋ pump activities in children with positive hypertensive family history （FH＋） are lower than that in children with negative hypertensive family history （FH-）.However, the alteration of ion pump activities induced by Ang Ⅱ in human umbilical artery smooth muscle cells （HUASMCs） with FH＋ or FH- is not clear.ObjectiveTo investigate Na＋, K＋-ATPase and Ca2＋-ATPase activities and mRNA expression level and the changes after Ang Ⅱ treatment in HUASMCs isolated from neonates with FH＋ or FH-. MethodsATPase activities in cultured HUASMCs were detected by spectrophotography. The mRNA expression of Na＋, K＋-ATPase α1-subunit and plasma membrane Ca2＋-ATPase isoform 1 （PMCA1） in FH＋ and FH- HUASMCs was measured by RT-PCR. ResultsNa＋, K＋-ATPase, Ca2＋-ATPase activities in FH＋ HUASMCs were higher than those in FH- group （P0.05）, but the mRNA expression of Na＋, K＋-ATPase α1-subunit and PMCA1 showed no difference between two groups.In FH- group, 24 hours after treatment, Ang Ⅱ （1×10-7 mol/L） elevated the activities of sodium pump and calcium pump, and up-regulated sodium pump mRNA expression （P〈0.01）; however higher concentration Ang Ⅱ （1×10-6 mol/L） suppressed the activities of sodium and calcium pump, and down-regulated sodium pump mRNA expression.Whereas, in FH＋ groups both concentration（10-6 and 10-7 mol/L） of Ang Ⅱ suppressed the activities of sodium pump and calcium pump （P〈0.01）, but only Ang Ⅱ （10-7 mol/L） down-regulated their mRNA expression （P〈0.05）.ConclusionThe activity of Na＋, K＋-ATPase and Ca2＋-ATPase are increased in FH＋ HUASMCs.Ang Ⅱ inhibits both Na＋ and Ca2＋ ion pumps activities in FH＋ HUASMCs.