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Objective:To investigate the effects of early-life (intrauterine and breastfeeding period) exposure to angiotensin Ⅱ type 1 receptor autoantibody (AT 1-AA) on lipid metabolism in offspring rats. Methods:Thirty-two AT 1-AA negative healthy nonpregnant specific pathogen free female Sprague Dawley rats weighing 150-170 g were randomly divided into two groups. Those in the immune group ( n=16) were subcutaneously injected with the mixture of an equal volume of Freund's adjuvant and the second extracellular loop of human-derived angiotensin Ⅱ receptor type 1 (AT1R-ECⅡ) repeatedly to establish the AT 1-AA-positive rat model by active immunization and those in the control group ( n=16) with normal saline solution. Before each immunization, blood samples were collected from the tail of rats to detect serum AT 1-AA levels of those rats in both groups, and the AT 1-AA-positive rat model was successfully established when the serum AT 1-AA was positive and its level reached a plateau. After eight weeks of immunization, the female rats in the two groups were mated with healthy AT 1-AA-negative male rats to conceive. Serum samples were collected from the maternal and offspring rats at the gestation of 18 days (G18), postnatal 21 days (P21), and from the normally fed offspring rats from the time of weaning to 12 weeks old (W12). Active immunization was not performed on the offspring throughout the experiment. The serum AT 1-AA levels of maternal and offspring rats were determined by enzyme-linked immunosorbent assay, and serum AT1-AA was positive when the ratio of AT1-AA level of the immune group over the control group ≥2.1. The blood lipid levels of maternal and offspring rats were measured by an automatic biochemical analyzer. Serum AT 1-AA levels, total cholesterol (TC), high-density lipoprotein-cholesterol [instead of high-density lipoprotein (HDL)], low-density lipoprotein-cholesterol, and free fatty acid levels of the offspring and maternal rats were determined for correlation analysis. Two independent sample t-test, linear regression analysis, and analysis of variance were adopted for statistical analysis. Results:(1) The serum levels of AT 1-AA in maternal rats at G18 and P21 in the immune group were significantly higher than those in the control group (G18: 1.170±0.190 vs 0.114±0.016, t=14.64; P21: 0.988±0.283 vs 0.084±0.006, t=9.57; both P<0.001). (2) The serum levels of AT 1-AA in the offspring at G18 and P21 in the immune group were significantly higher than those in the control group (offspring at G18: 0.948±0.220 vs 0.105±0.010, t=10.10; male offspring at P21: 0.758±0.273 vs 0.080±0.002, t=7.46; female offspring at P21: 0.774±0.274 vs 0.084±0.005, t=7.55; all P<0.001), which showed a positive correlation with those in maternal rats at the same period (offspring at G18: R=0.78; male offspring at P21: R=0.82; female offspring at P21: R=0.82; all P<0.05). However, there was no significant difference in the serum AT 1-AA level in offspring at W12 between the immune and control group ( P>0.05). (3) The serum levels of TC at G18 and P21, and HDL at P21 in maternal rats in the immune group were all higher than those in the control group [TC at G18: (2.36±0.32) vs (1.95±0.24) mmol/L, t=2.70; P21: (2.82±0.50) vs (2.18±0.26) mmol/L, t=3.41; HDL at P21: (1.94±0.33) vs (1.57±0.23) mmol/L, t=2.80; all P<0.05]. (4) Compared with the offspring in the control group, there was no significant change in lipid metabolism at G18 and W12 in the offspring in the immune group (both P>0.05). The serum levels of TC and HDL in male and female offspring at P21 in the immune group were higher than their counterparts in the control[TC in male offspring: (2.38±0.52) vs (1.83±0.30) mmol/L, t=2.73; HDL in male offspring: (1.44±0.32) vs (1.07±0.18) mmol/L, t=2.98; TC in female offspring: (2.50±0.72) vs (1.70±0.26) mmol/L, t=3.16; HDL in female offspring: (1.41±0.33) vs (1.00±0.14) mmol/L, t=3.41; all P<0.05]. (5) The serum levels of TC and HDL in male and female offspring at P21 in the immune group showed no correlation with those in maternal rats at P21 (all R<0.5, all P>0.05). The serum levels of HDL in male and female offspring at P21 in the immune group had a positive correlation with their own serum TC levels (male offspring: R=0.98; female offspring: R=0.97; both P<0.001) and also with their own serum AT 1-AA levels (male offspring: R=0.74, P=0.023; female offspring: R=0.91, P=0.001). The serum levels of TC in male and female offspring at P21 in the immune group had a positive correlation with their serum AT 1-AA levels (male offspring: R=0.72, P=0.030; female offspring: R=0.90, P=0.001). Conclusion:The early-life exposure to AT 1-AA may cause abnormal expression of TC and HDL in offspring rats.
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Objective:To evaluate the relationship between edaravone-induced inhibition of pressure overload-induced myocardial remodeling and angiotensin Ⅱ type 1 receptor (AT1R)/mitogen activated protein kinases (MAPKs)/steroidogenic acute regulatory protein (StAR) signaling pathway in rats.Methods:Thirty-six clean-grade healthy male Sprague-Dawley rats, aged 2 months, weighing 200-220 g, were divided into 3 groups ( n=12 each) using a random number table method: sham operation group (S group), pressure overload group (POL group) and edaravone group (E group). The cardiac pressure overload was induced by ligation of thoracic aorta for 8 weeks.After the model preparation, 0.9% sodium chloride 10 ml/kg was intraperitoneally injected daily in group POL, and edaravone 10 mg/kg was given instead in group E for 8 consecutive weeks.After the model was successfully established, the left ventricular ejection fraction (EF) and ventricular shortening fraction (FS) were measured by two-dimensional ultrasound.The animals were sacrificed by bloodletting, and the heart weight/body weight ratio (HW/BW ratio) was calculated.Myocardial tissues were obtained for determination of the cross-sectional area (MSA) after HE staining, the collagen volume fraction (CVF) (using Masson′s staining), the expression of AT1R and StAR (by immunohistochemistry), extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 MAPK phosphorylation levels (p-ERK1/2/ERK1/2 ratio and p-p38 MAPK/p38 MAPK ratio) (by Western blot) and the aldosterone content (by enzyme-linked immunosorbent assay). Results:Compared with group S, the HW/BW ratio, MSA and CVF were significantly increased, EF and FS were decreased, AT1R and StAR expression was up-regulated, and p-ERK1/2/ERK1/2 ratio, p-p38 MAPK/p38 MAPK ratio and aldosterone content were increased in group POL ( P<0.05). Compared with POL group, the HW/BW ratio, MSA and CVF were significantly decreased, EF and FS were increased, AT1R and StAR expression was down-regulated, and p-ERK1/2/ERK1/2 ratio, p-p38 MAPK/p38 MAPK ratio and aldosterone content were decreased in group E ( P<0.05). Conclusion:The mechanism of edaravone-induced inhibition of pressure overload-induced myocardial remodeling is probably associated with inhibiting the activation of AT1R/MAPKs/StAR signaling pathway in rats.
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Brain renin-angiotensin system (RAS) is closely associated with many pathophysiological processes of cardiocerebrovascular diseases,including stroke.The activation of the different components in RAS will produce specific biological effects.This article reviews the roles of brain RAS in the pathophysiological processes of ischemic stroke,especially the neuroprotective effect of ACE2/Ang-(1-7)/Mas axis.
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Angiotensin Ⅱ (Ang Ⅱ) is the main effector of the renin-angiotensin system (RAS). As a major regulator of blood pressure and cardiovascular homeostasis, Ang Ⅱis involved in the regulation of cell growth, proliferation and apoptosis. Ang Ⅱtype 1 receptor (AGTR1) is the important part of the RAS by mediating most of the Ang Ⅱ actions. Recently evidence suggested that AGTR1 correlated with tumor angiogenesis and poor patient outcome in cancer. Therefore, AGTR1 blockers have the potential to suppress the tumor angiogenesis and metastasis. This article intents to summarize the progression of the relationship between AngⅡ,AGTR1 and some malignant tumors.
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Objective To detect the expressions of angiotensin-receptor-1 (AT1R) and hypoxia-inducible factor (HIF)-1αin glomeruli and juxtaglomerular apparatus of different types of lupus nephritis (LN) patients, and analyze the correlation between them with systemic lupus erythematosus disease activity index (SLEDAI) complement 3, serum creatinine and 24-hour proteinuria in order to explore the role of the two factors in the pathogenesis of lupus nephritis (LN). Methods Between May 2010 and April 2016, a total of 90 patients with LN and 8 healthy controls were selected from Department of Rheumatology, Qujing Affiliated Hospital of Kunming Medical University and the First Affiliated Hospital of Kunming Medical University. The expressions of AT1R and HIF-1αin renal biopsy specimens were measured by streptavidin-perosidase (SP) of immunohistochemical stains. Pathological graphic analysis system was used for semi-quantitative estimate. Levels of SLEDAI, C3, serum creatinin and 24-hour proteinuria were also detected. Finally the relationshipbetween the two factors with clinical data was analyzed. The ANOVA test was used for intergroup comparison, and SNK-q test was used for the two groups comparison. Pearson's analysis was used for correlation analysis. Results The AT1R [(10.55 ±0.31)% vs (7.04 ±0.11)%] and HIF-1α [(10.51 ±0.52)% vs (8.96 ±0.31)%] in the glomeruli of typeⅠLN was significantly higher than healthy controls(all P<0.05). In the early phase of LN, RAS was activated and tissues were ischemic and hypoxic. The highest expression of AT1R (18.22 ± 2.11)% and HIF-1α (19.48 ±0.61)% in glomeruli was found in type Ⅳ LN, especially in juxtaglomerular apparatus, AT1R (19.98 ±0.21)% and HIF-1α(24.90 ±0.70)%. AT1R was positively correlated with HIF-1αin the glomer-ulus (r=0.949, P<0.01) and juxtaglomerular apparatus (r=0.762, P<0.05). AT1R and HIF-1αin juxtaglomerular apparatus was positively correlated with 24-hour proteinuria (r=0.756, P<0.05 and r=0.802, P<0.05). Conclusion High expressions of AT1R and HIF-1α have been shown in active LN biopsies. It proves that RAS is activated by ischemia and hypoxia, then it up-regulates HIF-1α expression. Our results suggest that the two factors may be associated with disease activity of LN.
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Objective To detect the expressions of angiotensin-receptor-1 (AT1R) and hypoxia-inducible factor (HIF)-1αin glomeruli and juxtaglomerular apparatus of different types of lupus nephritis (LN) patients, and analyze the correlation between them with systemic lupus erythematosus disease activity index (SLEDAI) complement 3, serum creatinine and 24-hour proteinuria in order to explore the role of the two factors in the pathogenesis of lupus nephritis (LN). Methods Between May 2010 and April 2016, a total of 90 patients with LN and 8 healthy controls were selected from Department of Rheumatology, Qujing Affiliated Hospital of Kunming Medical University and the First Affiliated Hospital of Kunming Medical University. The expressions of AT1R and HIF-1αin renal biopsy specimens were measured by streptavidin-perosidase (SP) of immunohistochemical stains. Pathological graphic analysis system was used for semi-quantitative estimate. Levels of SLEDAI, C3, serum creatinin and 24-hour proteinuria were also detected. Finally the relationshipbetween the two factors with clinical data was analyzed. The ANOVA test was used for intergroup comparison, and SNK-q test was used for the two groups comparison. Pearson's analysis was used for correlation analysis. Results The AT1R [(10.55 ±0.31)% vs (7.04 ±0.11)%] and HIF-1α [(10.51 ±0.52)% vs (8.96 ±0.31)%] in the glomeruli of typeⅠLN was significantly higher than healthy controls(all P<0.05). In the early phase of LN, RAS was activated and tissues were ischemic and hypoxic. The highest expression of AT1R (18.22 ± 2.11)% and HIF-1α (19.48 ±0.61)% in glomeruli was found in type Ⅳ LN, especially in juxtaglomerular apparatus, AT1R (19.98 ±0.21)% and HIF-1α(24.90 ±0.70)%. AT1R was positively correlated with HIF-1αin the glomer-ulus (r=0.949, P<0.01) and juxtaglomerular apparatus (r=0.762, P<0.05). AT1R and HIF-1αin juxtaglomerular apparatus was positively correlated with 24-hour proteinuria (r=0.756, P<0.05 and r=0.802, P<0.05). Conclusion High expressions of AT1R and HIF-1α have been shown in active LN biopsies. It proves that RAS is activated by ischemia and hypoxia, then it up-regulates HIF-1α expression. Our results suggest that the two factors may be associated with disease activity of LN.
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Objective To study the relationship of angiotensin Ⅱ type 1 receptor (AT1R) autoantibody (AT1-AA) and renal cell apoptosis induced by caspase-12 in diabetic nephropathy (DN)rats.Methods High-sucrose and high-fat diet and intraperitoneal injection of streptozotocin (35 mg/kg) were utilized to establish DN rat model.Serum AT1-AA was detected by enzyme-linked immunosorbent assay (ELISA) and renal cell apoptosis was detected by TUNEL staining.Furthermore,the mRNA levels of the endoplasmic reticulum stress (ERS) chaperone protein glucose regulated protein 78 (GRP78) and ERS-associated apoptosis protein caspase-12 were measured by real-time quantitative PCR.Additionally,the levels of GRP78 and caspase-12 protein were measured by Western blotting.Results The renal cell apoptosis rate in DN group was increased significantly (P ＜ 0.01),and the renal cells apoptosis rate in AT1-AA positive DN group was higher than that in AT1-AA negative DN group [(20.05±1.71)％ vs (13.24±4.93)％,P ＜ 0.01].The mRNA expressions of GRP78 and caspase-12 in DN group,in comparison to NC group,were increased significantly (P ＜ 0.01),as well as the proteins (P ＜ 0.01).And the expression of these mRNA and proteins had significant increment in AT1-AA positive DN rats when compared with AT1-AA negative DN rats (P ＜ 0.05).Conclusions AT1-AA can induce ERS in the renal tissue of DN rats,and promote renal cell apoptosis likely via the modulation of caspase-12 signaling pathway.
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Objective To examine the expression of autoantibodies against angiotensin Ⅱ type 1 receptor (AT1-AAs),monocyte chemoattractant protein-1 (MCP-1) and high-sensitivity C-reactive protein (hs-CRP) in patients of acute coronary syndrome (ACS),and study the role of AT1-AAs in plaque stability and pathogenesis of ACS.Methods Sixty patients with ACS were selected as ACS group,60 patients with stable angina pectoris (SAP) were selected as SAP group,and 60 healthy people were selected as control groups.The epitopes of the second extracellular loop of angiotensin Ⅱ type 1 receptor (165-191) were synthesized and used as antigen to screen the serum autoantibodies by enzyme-linked immunosorbent assay (ELISA).The peripheral blood levels of MCP-1 and hs-CRP were also evaluated.Results The positive rates of AT1-AAs in ACS group,SAP group and control group were 45.0％(27/60),21.7％(13/60) and 5.0％(3/60),respectively.The positive rates of AT1-AAs in ACS group and SAP group were significantly higher than those in control group,the positive rate of AT1-AAs in ACS group was significantly higher than that in SAP group,and there were statistical differences (P ＜ 0.01).The MCP-1 and hs-CRP levels in ACS group and SAP group were significantly higher than those in control group,the MCP-1 and hs-CRP levels in ACS group were significantly higher than those in SAP group,and there were statistical differences (P ＜ 0.01).The MCP-1 and hs-CRP levels in AT1-AAs positive patients in ACS group and SAP group were significantly higher than those in AT1-AAs negative patients,and there were statistical differences (P ＜0.01).Conclusions AT1-AAs may play an important role in the pathogenesis of ACS.Inducing the expression of inflammatory factor through AT1-AAs maybe an important mechanism for plaque instability.
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Objective To investigate the correlation of angiotensin Ⅱ type 1 receptor (AT1R) gene polymorphism with AT1R expression levels and brain edema after hypertensive intracerebral hemorrhage .Methods 45 operative patients with hypertensive intracerebral hemorrhage in the Affiliated Yongchuan Hospital of Chongqing Medical Univercity from December 2011 to August 2012 were collected as the experimental group and 45 operative patients with refractory epilepsy weres selected as the control group .The venous blood in the two groups were collected for detecting the AT 1R gene polymorphism ;The brain tissue was taken from lesions in operation ,then AT1R mRNA concentration was determined by RT-PCR and the AT1R protein level was determined by Western blot ;Head CT was performed on postoperative 1 ,3 ,5 d;the degree of cerebral edema was reflected by CT value . Results The levels of two kinds of genotype AT1R mRNA in the experimental group had no statistically significant difference(P>0 .05);the operative area CT value of AC genotype was significantly lower than that of AA genotype with statistical difference (P<0 .05);the ATIRmRNA of various genotypes ,protein level and cerebral edema in the control group had no statistical differences . Conclusion The AT 1R gene polymorphism has no obvious correlation with the concentration expression of AT 1R mRNA in the brain tis-sue;there is correlation between AT 1R protein level and AT 1R protein level and the cerebral edema degree in the brain tissue .
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Angiotensin (Ang Ⅱ),a main effector peptide of the renin-angiotensin system (RAS),mediates a hormonal action in the maintenance of blood pressure and electrolyte levels,and thus fluid homeostasis.Recent studies have implicated that it correlates with tumor growth,angiogenesis,metastasis and it has drawn more and more attention.Many studies show that Ang Ⅱ-AT1R/AT2R play crucial roles in tumor growth,metastasis,invasion and tumor angiogenesis,which are formed new targets for treating malignant tumors.
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Objective To study the correlation between the renin-angiotensin-aldosterone system angiotensinogen (AGT) gene M235T,angiotensin Ⅱ type 1 receptor (AGTR1) gene Al166C,aldosterone synthase (CYP11B2) gene -344C/T polymorphisms and large-artery atherosclerotic (LAA) stroke in a southern Chinese Han population.Methods Polymerase chain reaction and gene sequencing technology were used for the genotyping in patients with LAA and normal controls with AGT gene M235T,AGTR1 gene A1166C,and CYP11B2 gene - 344C/T polymorphisms in a southern Chinese Han population,and to determine the correlation between the 3 gene polymorphisms and LAA by binary logistic regression analysis.Results A total of 107 patients with LAA and 142 healthy controls were included in the study.The frequencies of the AGT gene 253TT genotype (66.36％ vs.50.70％,x2 =6.122,P =0.047) and T allele (79.44％ vs.70.07％ ％,x2 =5.581,P =0.018) in the LAA group were significantly higher than those in the control group.The frequencies of the AGTR1 gene 1166CC genotype (0％ vs.0％,x2 =1.494,P =0.222) and C allele (7.48％ vs.4.93％,x2 =1.399,P =0.237) in the LAA group were no significantly differences with those in the control group.The frequencies of the CYP11B2 gene - 344CC genotype (9.35％ vs.4.23％,x2 =3.603,P =0.165) and C allele (27.10％ vs.26.06％,x2 =0.069,P =0.793) in the LAA group were no significant differences with those in the control group.Binary logistic regression analysis showed that there was no significant correlation between the three gene polymorphisms and the simple LAA diseases.The frequencies of AGT gene 235TT genotype (68.00％ vs.41.90％,x2 =12.446,P =0.002) and T allele (79.33％ vs.64.76％,x2 =8.993,P =0.003) in the LAA patients complicated with hypertension were significantly higher than those in the normotensive control group.Logistic regression analysis showed that the odds ratio (OR) exposed to TT genotype was 2.153 (95％ confidence interval [CI] 0.789-5.872).The OR of T allele was 2.089 (95％ CI 1.285-3.396).Conclusions The AGT gene M235T polymorphism is not associated with the simple LAA in the southern Chinese Han population,but it may be associated with the risk of LAA complicated with hypertension;CYP11B2 gene -344C/T polymorphism and AGTR1 gene A1166C polymorphism are not associated with the onset of LAA in the southern Chinese Han population.
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Objective To investigate the expression of autoantibodies to the angiotensin Ⅱ type Ⅰreceptor (AT1-AA) and endothelin-1 (ET-1) in pregnant women's blood and explore their correlation with the pathogenesis of preeclampsia.Methods Ninety pregnant women who delivered from June 2011 to December 2011 in the First Affiliated Hospital of Zhengzhou University were chosen as the study objects.They were divided into mild preeclampsia group (n =30),severe preeclampsia group (n =30) and normal group (control group,n =30).The levels of AT1-AA and ET1 in maternal peripheral blood and umbilical cord blood were detected by ELISA,and the mRNA expression levels of AT1-AA and ET1 in placenta tissues were determined by reverse transcription (RT) PCR.Moreover,the correlation clinical indexes were detected and analysed.Results (1) The levels of AT1-AA and ET1 in maternal peripheral blood of preeclampsia [mild group:(114 ± 19) ng/L and (31 ± 9) ng/L,severe group:(145 ± 15) ng/L and (38 ± 10) ng/L] were both significantly higher than that of control group [(59 ± 5) ng/L,(17 ±4) ng/L].In addition,compared with mild group,the levels of AT1-AA and ET1 in severe group were significantly higher (P ＜0.05).(2) The levels of AT1-AA and ET1 in umbilical cord blood of preeclampsia [mild group:(105 ± 14) ng/L and (35 ±6) ng/L,severe group:(118 ± 14) ng/L and (40 ±5) ng/L] were significantly higher than that of control group [(61 ± 12) ng/L,(24 ± 5) ng/L].In addition,compared with mild group,the levels of AT1-AA and ET1 in severe group were significantly higher (P ＜0.05).(3) The mRNA expression levels of AT1-AA and ET1 in placenta tissues of mild group (0.313 ± 0.039,0.296 ±0.028) and severe group (0.568 ±0.052,0.577 ±0.046) were significantly higher than that in control group (0.198 ± 0.017,0.137 ± 0.012),and the levels in severe group were significantly higher than that in mild group (P ＜0.05).(4) There was an evident positive correlation between AT1-AA and ET1 levels of preeclampsia women's peripheral blood,umbilical cord blood and placenta (P ＜ 0.05).(5) The level of AT1-AA in umbilical cord blood of preeelampsia pregnant women was positively correlated with S/D value of umbilical artery (P ＜ 0.05),and negatively correlated with the weight of the birth and the placental (P ＜ 0.05).Conclusion The AT1-AA in the blood of pregnant women plays an important role in promoting the generation and development of preeclampsia by increasing the ET1 secretion.
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Objective To investigate the effects of cytokines on the expression of angiotensin Ⅱ type 1 receptor (AT1R) in vascular smooth muscle cells (VSMCs) in rats. Methods Primary cultured VSMCs from SD rat thoracic aorta were cultured in serum-free DMEM for 24 h, and then in DMEM supplemented with 10% fetal bovine serum for another 12 h. The cultured VSMCs were randomly divided into 5 groups (n =6 each): control group (group C); 10% cytokine group (group L); 50% cytokine group (group N); 100% cytokine group (group H) and L-arginine methy ester (L-NAME), an inhibitor of nitric oxide synthase) group. In group C, the cellswere cultured continuously for 12 h. In L, N and H groups, 10%, 50% and 100% cytokines (IL-1β 50 ng/ml +TNF-α 100 ng/ml + IFN-γ 500 ng/ml) were added to the culture medium respectively and the cells were then incubated for 12 h. In group L-NAME, 100% cytokines + L-NAME 5 mmol/L were added to the culture medium and the cells were then incubated for 12 h. The expression of AT1R mPNA and protin was determined by RT-PCR and Western blot respectively.Results Cytokines down-regulated AT1R mRNA and protein expression in a concentration-dependent manner (P ＜ 0.05 or 0.01). L-NAME reversed cytokines-induced changes in AT1R mRNA and protein expression ( P ＜ 0.01). Conclusion Cytokines can down-regulate the expression of AT1R in rat VSMCs and the mechanism is related to the NO synthesis.
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Objective To investigate the interference and associated mechanism of hnman tissue kallikrein (HK) gene on renal interstitial fibrosis in rats with 5/6 nephrectomy. Methods Human kallikrein cDNA was packed in a recombinant adeno-associated virus(rAAV)-based plasmid vector. The rAAV-HK was produced by transfection in 293 cells. Twenty-four male Wistsr rats were divided into sham operation and operation groups. The rats with 5/6 nephrectomy were randomly divided into simple operation, control and experiment groups. The rats in experiment group received single dose rAAV-HK via the tail vein with 1×1011 pfu. Before nephrectomy and every month after surgery until the rats were sacrificed, the caudal arterial pressure was measured using tail cuff blood pressure determinator. Three months after HK gene delivery, the rats were sacrificed. The expression of HK in rats was assessed by RT-PCR, Western blot and enzyme-linked immunosorbent assay (ELISA). The pathological changes of renal interstitium were evaluated by Masson stainning, and the distribution of bradykinin B2 receptor (BKB2R) and angiotensin Ⅱ typel receptor (ATIR) was examined by immunohistochemistry. The expressions of BKB2R, AT1R, p-MAPK protein in renal tissue were detected by Western blot. Results Three months after HK gene delivery, the systolic blood pressure of experiment group was significantly decreased compared with the control group [(163±13) nun Hg vs (217±16) mm Hg, P<0.01](1 mm Hg=0.133 kPa). Compared with sham rats, the rats in simple operation group and control group had much more renal interstitial collagen deposition and more serious fibrosis performance, but renal interstitial collagen deposition and fibrosis were significantly ameliorated in the rats of experiment group. In addition, the tubulointerstitial injury index of HK transgenic rats was significantly lower than that of the rats in control group (1.33±0.73 vs 3.01±0.62, P<0.01). Up-regnlating expression of bradykinn B2 receptor protein and down-regulating expression of AT1 receptor and p-MAPK protein were found in renal tissues of experimental group after three months (P<0.05). Conclusion HK gene delivery significantly alleviates renal interstitial fibrosis in rats with 5/6 nephrectomy through regulating the expression of bradykinin B2 receptor, AT1 receptor and p-MAPK in renal tissue.
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Objective To clarify the signaling mechanisms underlying angiotensin Ⅱ biphasic regulation of renal proximal Na+-HCO3- transport. Methods Different concentration Ang Ⅱ to the responses of Na+-HCO3- cotransporter (NBC) activity in isolated proximal tubules, with or without ATR, MAPK, cPLA2α, P450 blockade was compared in wild-type and Ang Ⅱ type 1a receptor (AT1aR)-deficient mice. The phospholipase of ERK was examined by Western blotting. AT1aR mRNA was examined by RT-PCR from kidney proximal tubules. Results (1)In isolated wild-type mouse, renal proximal tubules showed biphasic effects of Ang Ⅱ on NBC activity. Low concentration Ang Ⅱ (10-10 mol/L) increased NBC activity, but high concentration Ang Ⅱ (10-6 mol/L) decreased NBC activity. Olmcsartan (AT1 antagonist) blocked both stimnlatory and inhibitory effects of Ang Ⅱ on NBC activity, but PD98059 (mitogen-activated protein kinase inhibitor) blocked only the stimulatory effect of low concentration Ang Ⅱ ( 10-10 mol/L). (2)In AT1aR-deficient mice, only the stimulatory effect by high concentration of Ang Ⅱ (10-6 mol/L) was observed, which was blocked by olmesartan and PD98059. (3)In wild-type mice, pharmacological blockade of cPLA2 or P450 converted the inhibition effect by high concentration Ang Ⅱ (10-6 mol/L) to the stimulation, which was blocked by olmesanan and PD98059. These results indicated that the extracellular sigual-regulated kinase (ERK) activation via AT1 mediated only the stimulatory effect of Ang Ⅱ, while the cPLA2α/P450 activation via AT1 mediated the inhibitory effect of Ang Ⅱ independently of ERK. The analysis of ERK phosphorylation by Ang Ⅱ also supported a view that the cPLA2α/P450 pathway worked to suppress the ERK activation. Conclusions Ang Ⅱ activates ERK and cPLA2α with different concentration dependency via AT1. The balance between ERK and cPLA2α activities determines the final responses to Ang Ⅱ in intact proximal tubules.
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Objective To explore the glomerular change of renin-angiotensin system (RAS) expression in ATIaR gene knockout mice and its effects on extracellular matrix (ECM) remodeling under diabetic condition. Methods ATlaR knockout mice were generated previously. Hyperglycemia was induced by peritoneal injection of streptozotocin in ATIaR knockout mice and wild type mice. Normal AT1aR knockout mice and wild type mice were used as control group. Twelve weeks later, kidneys were harvested and frozen quickly in dry ice-acetone. Glomendi were collected by laser capture microdissection and total RNA was extracted, mRNA expression of AT1aR, AT1bR, AT2R, angiotensinogen, ACE, renin, and CYP11B2 was assessed by real-time PCR. ECM accumulation was evaluated by PAS staining. Protein levels of transforming growth factor β1(TGF-β1), type 1 plasminogen activator inhibitor(PAI-1), monocyte chemotactie protein 1(MCP-1) and renin were semi-quantitated by immunostaining. Results Compared to the wild type, mRNA expression of AT1bR, angiotensinogen, renin, CYP11B2 within glomeruli was upregulated significantly in ATlaR knockout mice (P<0.05), but no change of ACE expression was found in these two groups. AT2R protein was poorly detected in AT1aR knockout glomeruli and downregulated in wild type glomemli. ECM accumulation was significanfly increased associated with the parallel increase in TGF-β1, PAI-1, MCP-1 and renin within glomendi (P <0.05). Conclusions AT1aR gene knockout cannot improve ECM deposition in diabetic nephropathy. The compensate change of RAS components may be involved in this scenario: upregulation of AT1bR, downregulation of AT2R. CYP11B2 and renin may function in a novel pathway.
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ObjectiveTo investigate the effect of all-trans retinoic acid (atRA) on the renin-angiotensin system (RAS) in 5/6 renal ablation model. MethodsAtRA was administered to 5/6 renal ablation rats by three dosages: 5 mg·kg-1·d-1 (n=8), 10 mg·kg-1d-1 (n=8) and 20 mg·kg-1 d-1 (n=8) and vehicle (vehicle group, n=8) for 10 weeks. Healthy rats consisted of shamoperation group (n =8). The level of renin and angiotensin Ⅱ in renal tissues were measured by radioimmunoassary. The level of angiotensin type 1 receptor (AT1R) in remnant renal cortex was measured by Western blot. The mRNA expression levels of two subunits of activative protein 1(AP-1),c-jun and c-fos was quantitated by real-time PCR. ResultsAfter 10 weeks of atRA treatment by gavarge, artery blood pressure decreased (P＜0.05). AtRA reduced the levels of renin (P＜0.05) and angiotensin Ⅱ (P＜0.05) in kidney and down-regulated the expression of AT1R protein in renal cortex. Larger dose of atRA (20 mg·kg-1·d-1) performed higher activity in inhibiting renin and AT1R. Compared with vehicle group, atRA could significantly inhibit the expression of renal c-jun and c-fos mRNA (P＜0.05). Conclusion atRA can decrease the over-expression of main components of RAS.
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Objective To investigate the effect of 12-lipoxygenase (12-LO) on the angiotensinⅡtype 1 receptor(ATlR) expression in mesangial cells (MC).Methods p38 MAPK activation and ECM protein expression were determined using AngⅡ-stimulated MC derived from normal and 12-LO knockout mice.AT1R expression was determined using 12-LO product 12(S)- HETE-stimulated MC,MC transfected with 12-LO gene and microdissected glomeruli derived from 12-LO knockout mice.RT-PCR and Western blot were used for evaluating mRNA and protein expression respectively.Results AngⅡstimulation increased p38 MAPK activation and ECM protein expression in normal MC,but not in MC derived from 12-LO knockout mice.Time-dependent and dose-dependent experiment showed that 12 (S)- HETE increased AT1R protein' expression in MC. Similarly,12 (S)-HETE increased AT1R mRNA expression in MC compared with control MC (P＜0.01). Furthermore,AT1R expression was lower in glomeruli derived from 12-LO knockout mice relative to genetic controls (P＜0.01) and MC stably overexpressing 12-LO had greater AT1R protein and mRNA expression relative to control MC (P＜0.01).Conclusion 12-LO activation can upregulate ATIR expression in MC.
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BACKGROUND: The purpose of this study was to investigate whether brain AT1 receptor stimulation contributes as a hypertensive mechanism to deoxycorticosterone acetate (DOCA)-salt hypertension. METHODS: 1) Acute injection:Losartan (1 mg/4 uL) or artificial cerebrospinal fluid (aCSF) was injected into the lateral cerebral ventricle (icv) of conscious control uninephrectomized Wistar rats or rats with DOCA-salt at 2 or 4 weeks, and mean arterial pressure (MAP) and heart rates (HR) were recorded. 2) Chronic injection:Using osmotic minipump, losartan (1 mg/kg/d) or aCSF was injected to a sham group or three DOCA-salt rat groups [icv-aCSF, icv-losartan, sc-losartan (subcutaneous) groups] for 4 weeks, after which the MAP and HR were recorded in addition to the weights of the left (LV) and right ventricles (RV) and kidneys. RESULTS: 1) Acute injection: In rats treated with DOCA-salt, resting MAP significantly increased compared to the control group [144+/-6 mmHg (2 weeks), 170+/-5 mmHg (4 weeks) vs 115-120 mmHg (controls)]. MAP decreased significantly (2 weeks, 4 weeks) at 4, 8, 24 hours after icv injection of losartan to the level of the control group. 2) Chronic injection: The general trend showed that MAP decreased more in the icv-losartan group than in the icv-aCSF group (127+/-15.2 mmHg vs 141.1+/-5.5 mmHg, p=0.0578). In all DOCA-salt groups, no differences in RV weight were found. In the icv-aCSF and sclosartan groups, the kidney weight increased compared to the control group, but there was no difference in LV and kidney weight between the icv-losartan group and the control group. CONCLUSION: Normalization of MAP after acute or chronic icv administration of the AT1 receptor antagonist suggests that the stimulation of the brain AT1 receptor plays a significant role in the development and maintenance of hypertension in the DOCA-salt hypertensive rat model. Losartan icv injection appeared to have a protective effect on the heart and kidney.
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Animals , Rats , Angiotensin II , Arterial Pressure , Brain , Cerebral Ventricles , Cerebrospinal Fluid , Desoxycorticosterone , Heart , Heart Rate , Heart Ventricles , Hypertension , Kidney , Losartan , Models, Animal , Rats, Wistar , Receptor, Angiotensin, Type 1 , Weights and MeasuresABSTRACT
Objective To observe the expression of both type 1 (AT1) and type 2 (AT2) receptors of angiotensin Ⅱ (AngⅡ) in human hypertrophic scars, and to explore theirs role in collagen synthesis of fibroblasts in human hypertrophic scars. Methods The expression of both AT1 and AT2 receptors in fibroblasts of hypertrophic scars was detected with immunohistochemical staining and radioligand receptor binding assay. Collagen synthesis was examined in cultured in vitro fibroblasts of hypertrophic scars by measuring [~3H]proline incorporation into collagenous proteins. Results Positive staining signals of both AT1 and AT2 receptors were found in fibroblasts of hypertrophic scars. Similar results were also got in cultured in vitro fibroblasts of hypertrophic scars, expression level of AT1 and AT2 receptors were 10.69?2.15fmol/10~6cells and 4.9?1.05fmol/10~6cells respectively. In cultured in vitro fibroblasts, AngⅡ may accelerate the collagen synthesis significantly (P