To investigate the mechanisms of splanchnic hyperdynamics in portal hypertension (PHT), angiotensin Ⅱ(A-Ⅱ) receptor maximal binding capacity (Bmax) and dissociation constants (Kd) of splanchnic blood vessels in rats with prehepatic PHT were studied by radioligand binding analysis. The results showed that the A-Ⅱ receptor Bmax in the superior mesenteric artery and portal vein of PHT animals (206.9±39.3 fmol/mg protein and 31.5±9.2 fmol/mg protein respectively) was all significantly lower than that of the controls (297.2±44.7 fmol/mg protein and 53.4±12.1 fmol/mg protein respectively, Ｐ＜0.01). The A-Ⅱ receptor Kd in the superior mesenteric artery was markedly increased in PHT animals (1.03±0.11 nmol/L) compared with that in controls (0.88±0.08 nmol/L, Ｐ＜0.05). In the portal vein, the A-Ⅱ receptor Kd in PHT animals was slightly higher than in controls, but no significant difference was observed between the two groups. These results suggest that the vascular hyporesponsiveness to A-Ⅱ in PHT is caused partially by a reduction in number and a decrease in affinity of vascular A-Ⅱ receptors, and these changes may possibly lead to the formation of hyperdynamic circulation.
摘要:目的: 探讨激活转录因子(ATF1)在血管紧张素Ⅱ(AngⅡ)诱导血管平滑肌细胞(VSMCs)中NOX1基因表达增加的作用。 方法 :体外培养大鼠主动脉VSMCs,用荧光实时定量逆转录PCR(Realtime RTPCR)检测NOX1基因表达的量,Western Blot检测ATF1蛋白在AngⅡ的刺激是否引起NOX1基因的高表达并用RNA干扰(RNAi)技术转染VSMCs使ATF1基因沉默来观察NOX1的表达。 结果 :AngⅡ能够诱导 NOX1基因的表达增加以及增强ATF1的磷酸化及活性,ATF1基因沉默反过来可抑制AngⅡ诱导的NOX1基因表达的增加。 结论 :在大鼠的VSMCs中,ATF1是介导NOX1基因表达的一个必须的转录因子。Abstract: Objective: To detect the role of activating transcription factor (ATF1) involved in angiotensinⅡ(AngⅡ) stimulated NOX1 gene expression.Methods :Rat aortic vascellum smooth muscle cells(VSMCs) were cultured in vitro.Use Realtime RTPCR to measure the expression of NOX1 gene.Western Blot Analysis was carried out to test the activity of ATF1 protein. RNA interference was used and transfected into VSMCs to knockdown ATF1 gene expression, and then measured NOX1 gene expression.Results : AngⅡ stimulated NOX1 gene expression and phosphorylation of ATF1 Gene silencing of ATF1 attenuated the upregulation of NOX1 mRNA by AngⅡ. Conclusion :ATF1 is an essential transcription factor that mediates expression of NOX1 gene in VSMCs by AngⅡ.
目的:探讨血管紧张素Ⅱ受体拮抗剂(ARB)对PAF患者P波离散度的影响。方法:观察48 例阵发性AF患者的最宽P 波和P 波离散度,并与ARB干预治疗3 个月后进行对比分析。结果:ARB治疗3个月后最宽P波、P 波离散度及P 波离散度≥40 ms的例数与治疗前比较差异有统计学意义 (Plt;0.05或lt;0.01)。结论:ARB能减轻PAF患者心房结构重构及电重构,减少AF的发生。
Objective To investigate the preventive effect of simvastatin，a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor，on hypoxic pulmonary hypertension and the relation between it and the angiotensin Ⅱ receptor-1（AT1R） expression in pulmonary arteriole.Methods Thirty male Sprague-Drawley rats were randomly allocated into three groups：a control group，a hypoxic group and a simvastatin preventive group.The animal model of hypoxic pulmonary hypertension was established by exposing the rats to normobaric hypoxic condition（8 h×6 d×3 w），and the preventive group were treated with simvastatin 10 mg/kg before hypoxic processing while the control and hypoxic groups were treated with sodium chloride.The mean pulmonary pressure（mPAP），serum cholesterol concentration，right ventricular hypertrophy index [RV/（LV+S）]，percentage of the wall thickness in the external diameter（WT%），percentage of the wall area in the total vascular area（WA%），and the AT1R expression in pulmonary arterioles were measured.Results When compared with the hypoxic group，in the preventive group，the mPAP and RV/（LV+S）obviously reduced [（22.6±3.86）mm Hg vs （29.3±2.27）mm Hg，（25.13±0.75）% vs （33.18±1.58）%，Plt;0.01 respectively]，the indices of wall thickness of rat pulmonary arteriole and area also decreased significantly [WT%：（15.98±1.96）% vs （25.14±1.85）%；WA%：（54.60±3.94）% vs 74.77±4.52）%；Plt;0.01 respectively]，and the positive degree of AT1R still lessened noticeably（1.23±0.09 vs 1.57±0.13，Plt;0.01）.All of the indices above in the hypoxic group increased markedly compared with the control group（Plt;0.01 respectively）.However，the differences of serum cholesterol among three groups were not significant（Pgt;0.05）.Conclusions Simvastatin can suppress the expression of AT1R in pulmonary vessel and prevent hypoxic pulmonary hypertension.
Objective To investigate the role of angiotensin-II type 1 receptor ( AT1) antagonist in treatment of acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) . Methods Animal model of ALI/ARDS was induced by cecal ligation and perforation ( CLP) . ALI/ARDS animals received a separate intraperitoneal injection of several concentrations( 5, 10, 15, 20, 25 mg/kg) of AT1 inhibitor losartan after CLP, then the changes of lung injury and 7-day survival were measured. Results Oxygenation index and lung wet to dry weight ratio ( W/D) showed an improving trend when losartan was administered at doses of 5 to 15 mg/kg in ALI/ARDS rats, but aggravated above the dose of 15 mg/kg. Losartan ( 15 mg/kg) treatment significantly alleviated pulmonary edema after CLP operation, and decreased serumlevels of TNF-α, IL-6, andIL-1β [ TNF-α: ( 554. 1 ±62. 7 ) pg/mL vs. ( 759. 2 ±21. 5 ) pg/mL, P lt; 0. 01; IL-6: ( 1227. 3 ±130. 0) pg/mL vs. ( 2670. 4 ±174. 1) pg/mL, P lt; 0. 01; IL-1β: ( 444. 0 ±38. 6) pg/mL vs. ( 486. 6 ±61. 7)pg/mL, P lt; 0. 05] . 7-day survival rate also increased in losartan treatment group at a dose of 15 mg/kg( 6. 7% vs. 0 ) . Conclusions The AT1 inhibitor, losartan, can significantly prevent lung injury in ALI/ARDS after CLP, and improve the 7-day survival rate.
Vascular smooth muscle cells (VSMCs) phenotype switching plays an essential role in the pathogenesis of various vascular diseases. The present study aims to investigate the role of receptor-interacting protein kinases 1(RIPK1) in VSMCs phenotypic switching induced by Angiotensin Ⅱ(Ang Ⅱ). Expression of mRNA and protein of RIPK1, markers of VSMCs phenotypic switching and secretion, phosphorylation of the P65 subunit of NF-κB were measured by real-time PCR and Western blot. Meanwhile, EdU incorporation assay and wound scratch assay were performed to determine the cell proliferation and migration respectively. At the same time, Necrostatin-1(Nec-1, an known RIPK1 inhibitor) and RIPK1-specific small interference RNA (siRNA) were used to inhibit the expression of RIPK1. The experimental data demonstrated that the mRNA and protein levels of RIPK1 and P65 phosphorylation were increased significantly in the process of VSMC phenotypic switching induced by Ang II. Moreover, the expression of RIPK1 and P65 phosphorylation were significantly down-regulated in VSMCs pretreated with Nec-1 or trans-fected with RIPK1-siRNA. Furthermore, the proliferation, secretion and migration of VSMCs were also markedly suppressed after inhibition of RIPK1 by Nec-1 or its specific siRNA. The results suggested that RIPK1 might be involved in VSMC phenotypic switching induced by Ang II, which was possibly via up-regulating the NF-κB signaling pathway.