Qianfeng Jiang

e0039 Effects of Lisinopril on the activities and mRNA expression of ion pumps in aortic smooth muscle cells from spontaneously hypertensive rats

Objectives To explore the effects of Lisinopril upon the activities of Na+, K+-ATPase and Ca2+-ATPase and mRNA expression levels of Na+, K+-ATPase a1-subunit and plasma membrane Ca2+-ATPase isoform 1 (PMCA1) in cultured thoracic aorta vascular smooth muscle cells (ASMCs) isolated from spontaneously hypertensive rats (SHR). Methods ASMCs were divided into four groups: Wistar-Kyoto (WKY) control, SHR control, Lisinopril (1×10−5) intervened SHR group and Lisinopril (1×10−6) intervened SHR group. The activities of ion pumps were detected by spectrophotography and mRNA expressions were measured by real time PCR. The content of Angiotensin II (Ang II) in cells-cultured medium were detected by radioimmunoassay. Results The activities of Na+, K+-ATPase, Ca2+-ATPase and the mRNA expression levels of Na+, K+-ATPase a1-subunit and PMCA1 in ASMCs from SHR were significantly lower than those from WKY control (p<0.01). Lisinopril significantly increased the activities of Na+, K+-ATPase and Ca2+-ATPase and mRNA expression levels of Na+, K+-ATPase a1-subunit and PMCA1 in ASMCs from SHR (p<0.01). Ang II content of culture medium in ASMCs from SHR was significantly more than those from WKY control (p<0.05), Lisinopril attenuated Ang II content of ASMCs culture medium from SHR (p<0.05). Conclusions The decreased activities of Na+, K+-ATPase and Ca2+-ATPase may be related to their lower expression of the mRNA in ASMCs from SHR. The Lisinopril may increase the activities of two ion pumps and upregrulae the mRNA expression of Na+, K+-ATPase a1-subunit and PMCA1 in ASMCs from SHR through blocking the generation of Ang II.

e0037 Effects of enalapril and irbesartan on aorta remodelling and ion pumps in renovascular hypertensive rats

Objective To investigate the effects of single-drug or combination therapy of enalapril and irbesartan on aorta remodelling and its mechanisms. Methods Renovascular hypertensive rats (RHD) induced by two-kidney one-clip method were treated with normal saline (model group, n=6), enalapril [10 mg/ (kg d), n=6], irbesartan [50 mg/ (kg·d), n=6] and enalapril+irbesartan [5 mg/ (kg d)+25 mg/ (kg d), n=6] for 6 weeks. Six sham-operated rats were used as controls. Aortic morphology and structural changes in the media were observed by HE staining, immunohistochemistry and Masson staining. The content of Angiotensin II (Ang II) was measured by radioimmunoassay. The activities and mRNA levels of Na+ pump and Ca2+ pump in aortic media were determined by enzyme assay and real-time PCR respectively. Results The media area of aorta and the Ang II content were significantly increased in model group, while the activities and the mRNA levels of Na+ pump and Ca2+ pump in aortic media were obviously decreased, and Na+ pump and Ca2+ activities were increased in enalapril group and irbesartan group (p<0.01). The Ang II content was obviously decreased in enalapril group, while increased in irbesartan group (p<0.01). The mRNA levels of sodium pump a1-subunit and plasma membrane calcium pump isoform 1 (PMCA1) in aorta smooth muscle tissue were significantly increased in enalapril group (p<0.01). The amelioration of blood pressure, Na+ pump and Ca2+ pump activities, media area and thickness in combination group was significantly better than single-drug intervened group (p<0.01). Conclusion The amelioration of aorta remodelling induced by enalapril and irbesartan may be associated with the increase of Na+ pump and Ca2+ pump activities. There may be some synergistic effects on ameliorating of Na+ pump and Ca2+ pump activities and aorta remodelling from combination of the two drugs. The effect of enalapril on Na+ pump and Ca2+ pump activities may be mediated by increasing their mRNA expression.

e0595 AngiotensinII modulates ion pumps of smooth muscle cells derived from umbilical artery of human neonates with hypertensive family history

Objective To investigate sodium pump and calcium pump activities and mRNA expression level and the changes after AngiotensinII (AngII) treatment in human umbilical artery smooth muscle cells (HUASMCs) isolated from neonates with positive hypertensive family history (FH+) or with negative hypertensive family history (FH-). Methods Ion pump activities in cultured HUASMCs were detected by spectrophotography. The mRNA expression of sodium pump α1-subunit and plasma membrane Ca2+-ATPase isoform 1 (PMCA1) in FH+ and FH- HUASMCs was measured by RT-PCR. Results Sodium pump, calcium pump activities in FH+ HUASMCs were higher than those in FH- group (p<0.05), but the mRNA expression of sodium pump α1subunit and PMCA1 showed no difference between two groups. In FH- group, after 24-h treatment, AngII (1×10−7 mol/L) elevated the activities of sodium pump (4.62±0.26 vs 3.52±0.33) and calcium pump (4.00±0.31 vs 3.01±0.32), and up-regulated sodium pump α1-subunit mRNA expression (0.946±0.099 vs 0.697±0.050, n=5, p<0.01), however higher concentration AngII (1×10−6 mol/L) suppressed the activities of sodium (2.47±0.27) and calcium pump (1.79±0.27), and down-regulated sodium pump mRNA expression (0.445±0.065). Whereas, in FH+ groups, both concentration (10−6 and 10−7 mol/l) of AngII suppressed the activities of sodium pump (3.49±0.34, 2.21±0.23 vs 4.70±0.44) and calcium pump (2.85±0.31, 1.87±0.16 vs 4.27±0.48), but only AngII (10−7 mol/l) down-regulated their mRNA expression (α1-subunit: 0.515±0.133 vs 0.885±0.097, PMCA1: 0.165±0.049 vs 0.397±0.046, n=5, p<0.01). Conclusions The activity of sodium pump and calcium pump is increased in FH+ HUASMCs. AngII inhibits both Na+ and Ca2+ ion pumps activities and mRNA expression in FH+ HUASMCs, and may have biphasic effects on ion pump activities and mRNA expression in FH- hUASMCs.

e0340 Actions of Irbesartan on ATPase activity and angiotensin ii in blood vessels from renal hypertensive rats

Objective To explore the effects of irbesartan on activities of Na+-K+-ATPase, Ca2+-ATPase, Angiotensin II (AngII) and vascular remodelling in renal hypertensive rats (RHRs). Methods Renovascular hypertension was induced by two kidney-one clip method. Eighteen RHRs were randomly divided into 3 groups: RHR model group (n=6), irbesartan treated group [50 mg/(kg d), n=6], withdrawal group (n=6). Six rats were included in sham operation group. Blood pressure was measured before and after using irbesartan. Thicknesses of vascular wall (TVW) of thoracic aorta and mesenteric artery were measured after 8 weeks. ATPase activities were determined by enzymatic colorimetric method. AngII level was detected by radioimmunoassay. Results Compared to the sham operation group, blood pressure, TVW, AngII levels of plasma and blood vessels were increased in RHR. The activities of Na+-K+-ATPase and Ca2+-ATPase were decreased in RHR. Blood pressure and the TVW of mesenteric artery were significantly decreased by irbesartan treatment. An increased AngII level and activity of Ca2+-ATPase in thoracic aorta and mesenteric artery were also found [thoracic aorta: (11.9±1.9) vs (7.5±1.6) μmol Pi/(h·mg pro); mesenteric artery: (11.6±1.9) vs (8.2±0.8) μmol Pi/(h·mg pro), both p<0.01]. No change of Na+-K+-ATPase activity was found after irbesartan treatment. After one-week discontinuation of treatment, blood pressure was significantly elevated, the activity of Ca2+-ATPase of thoracic aorta [(7.6±1.4) μmol Pi/(h·mg pro)] and mesenteric artery [(6.9±1.3) μmol Pi/(h·mg pro)] was decreased (both p<0.01). There was a significant negative correlation between AngII and the activity of Ca2+-ATPase in RHR. Conclusions The vascular remodelling of RHR may be associated with decreased vascular ATPases activities. Irbesartan can reverse vascular remodelling partially by increasing Ca2+-ATPase activity.

e0121 The effects of endothein-1 and BQ-123 on ATPase activity and mRNA expression in aortic smooth muscle cells from spontanously hypertensive rats

Aim To study the effects of endothelin-1 (ET-1) and BQ-123 (ETA receptor antagonist) on activities and mRNA expression of ATPase in aortic smooth muscle cells (ASMCs) from spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Methods The ASMCs were isolated from SHR and WKY rats. The ATPase activities of cultured ASMCs were determined by spectrophotography. The mRNA levels of Na+, K+-ATPase α1-subunit and plasma membrane Ca2+-ATPase isoform 1 (PMCA1) were measured by semiquantitative reverse transcription PCR (RT-PCR). Results 3 different concentrations of ET-1 (1×10−9, 1×10−8 and 1×10−7 mol/l) significantly attenuated the activities of Na+, K+-ATPase and Ca2+-ATPase and PMCA1 mRNA expression (all p<0.01) in ASMCs from SHR. Three different concentrations of BQ-123 (1×10−8, 1×10−7 and 1×10−6 mol/l) obviously prevented ET-1 mediated the inhibition of two kinds ATPase activities (all p<0.01) and downregulation of PMCA1 mRNA expression (p<0.01). But the mRNA expression level of Na+, K+-ATPase α1-subunit had no alteration after intervened by ET-1 (p>0.05). Conclusions ET-1 may suppress Na+, K+-ATPase, Ca2+-ATPase activities via ETA receptor. The influence of ET-1 on Ca2+-ATPase activity may partially occur in the transcriptional level. BQ-123 can inhibit the effect of ET-1 on two kinds ATPase activities of ASMCs in SHR by blocking the ETA receptor.

e0038 Effects of Angiotensin II on ATPases in aortic vascular smooth muscle cells from Wistar-Kyoto rats and spontaneously hypertensive rats

Aim To explore the effects of Angiotensin II on the activities of Ca2+-ATPase, Na+, K+-ATPase and mRNA expression levels of the plasma membrane Ca2+-ATPase isoform 1 (PMCA1) and Na+, K+-ATPase α1-subunit in cultured thoracic aortic vascular smooth muscle cells (AMSCs) from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR). Methods AMSCs isolated from 14-week-old male WKY rats and SHR were cultured and treated with different concentrations (1×10−9, 1×10−8, 1×10−7 mol/l) of Angiotensin II. The activities of Ca2+-ATPase, Na+, K+-ATPase were measured by biochemistry and enzymology. RT-PCR assay was employed to determine the relative levels of PMCA1 and Na+, K+-ATPase α1-subunit mRNA in AMSCs. Results Low and moderate concentration of Angiotensin II significantly increased the activity of Ca2+-ATPase and up-regulated PMCA1 mRNA level in AMSCs from Wistar-Kyoto rats, while high concentration of Angiotensin II inhibited Ca2+-ATPase activity and down-regulated PMCA1 mRNA level. Three different concentration of Angiotensin II significantly decreased the activity of Ca2+-ATPase and PMCA1 mRNA level in AMSCs from SHR. Three different concentrations of Angiotensin II stimulated the activity of Na+, K+-ATPase and increased its α1-subunit mRNA expression in AMSCs from WKY rats. Low and moderate concentration of Angiotensin II did not affect the activity of Na+, K+-ATPase in SHR, while high concentration of Angiotensin II significantly suppressed the activity and α1-subunit mRNA level of Na+, K+-ATPase. Conclusions In WKY rats, Angiotensin II may have biphasic effects on Ca2+-ATPase activity and PMCA1 mRNA expression, and may promote the activity and α1 subunit mRNA expression of Na+, K+-ATPase in a dose-dependent manner in AMSCs. In SHR, Angiotensin II can inhibit Ca2+-ATPase activity and PMCA1 mRNA expression, and only high dose of Angiotensin II can suppress the activity and α1 subunit mRNA expression of Na+, K+-ATPase in AMSCs.