Biological function of miRNA-145-5p in angiotensin II induced renal inflammation

Objective:Chronic kidney disease(CKD)is a progressive disorder characterized by intricate structural and functional alterations in the kidneys,attributable to diverse causative factors.Notably,the therapeutic promise of miR-145-5p in addressing renal pathologies has been discerned.This investigation seeks to elucidate the functional role of miR-145-5p in injured kidneys by subjecting human glomerular mesangial cells(HGMCs)to stimulation with Angiotensin II(AngII).Materials and Methods:Cellular viability and the levels of inflammatory mediators were evaluated utilizing Cell Counting Kit-8(CCK-8),quantitative real-time polymerase chain reaction(qRT-PCR),and western blot methodologies,both in the presence of AngII incubation and in scenarios of miR-145p overexpression and downregulation.Furthermore,the cell cycle dynamics were elucidated through Fluorescence-activated Cell Sorting(FACS)analysis.Results:AngII incubation induced an upregulation of miR-145-5p and inflammatory factors including Intercellular Adhesion Molecule 1(ICAM-1),Interleukin 6(IL-6),Interleukin 8(IL-8),and Interleukin 1β(IL-1β).Additionally,it elevated the expression of Cyclin A2,Cyclin D1,and the G2/M cell cycle ratio.Conversely,inhibition of miR-145-5p heightened the levels of inflammatory factors and cell cycle regulators induced by AngII incubation.Reduced expression of miR-145-5p correlated with a downregulation of Interleukin 10(IL-10)expression,concurrently promoting HGMC proliferation under AngII stimulation.Moreover,ectopic miR-145-5p expression demonstrated a reduction in inflammatory factors,cell cyclin regulators,G2/M cell cycle ratio,and overall proliferation.Conclusion:MiR-145-5p exhibited inhibitory effects on the inflammatory response and proliferation induced by Angiotensin II in HGMCs,showcasing its potential as a therapeutic avenue for the treatment of kidney injury.

Impacts of angiotensin II on retinal artery changes in apolipoprotein E deficient mice

AIM:To investigate the impacts of angiotensin II(Ang II)on retinal artery changes in apolipoprotein E deficient(apoE^(-/-))mice.METHODS:ApoE^(-/-)male mice were infused by minipumps with Ang II at 1000 ng/kg·min(Ang II group)or saline(control group)for 28d.They were underwent ophthalmic fundus examination on day 0,14,and 28 of infusion.Histopathologic examination,ribonucleic acid(RNA)sequencing and local Ang II measurement of retinas were conducted.RESULTS:Ophthalmic fundus examination showed Ang II infusion promoted the formation of retinal arterial aneurysm-like lesions on day 28.Optical coherence tomography revealed the ganglion cell and inner plexiform layer(GCIPL)thickness in the control group was significantly thinner than that in Ang II group(P<0.001).Hematoxylin-eosin staining demonstrated diffused swelling of GCIPL layer and its disordered structure in Ang II group.Transmission electron microscopy showed Ang II infusion caused aggravation of atherosclerotic lesions,including increased swelling,roughness,disorganization of the retinal vasculature,and vacuoles formation.RNA-sequencing and gene ontology enrichment analysis demonstrated that the structure and function of cellular membrane might be disturbed and visual function might be compromised by Ang II.The local level of Ang II was higher in Ang II infusion group but did not show significant differences compared to the control group(P=0.086).CONCLUSION:Ang II infusion promotes the formation of retinal arterial aneurysm-like lesions in apoE^(-/-)mice,causing aggravation of atherosclerotic lesions,more severe disorganization of the retinal vasculature and disturbance of the cellular membrane.

Influence of Angiotensin II on α1-Adrenergic Receptors Function in Rat Aorta and Expression in Vascular Smooth Muscle Cells

Angiotensin II (Ang II) is the main mediator of the Renin-Angiotensin-System acting on AT1 and other AT receptors. It is regarded as a pleiotropic agent that induces many actions, including functioning as a growth factor, and as a contractile hormone, among others. The aim of this work was to examine the impact of Ang II on the expression and function of α1-adrenergic receptors (α1-ARs) in cultured rat aorta, and aorta-derived smooth muscle cells. Isolated Wistar rat aorta was incubated for 24 h in DMEM at 37˚C, then subjected to isometric tension and to the action of added norepinephrine, in concentration-response curves. Ang II was added (1 × 10−5 M), and in some experiments, 5-Methylurapidil (α1A-AR antagonist), AH11110A (α1B-AR antagonist), or BMY-7378 (α1D-AR antagonist), were used to identify the α1-AR involved in the response. Desensitization of the contractile response to norepinephrine was observed due to incubation time, and by the Ang II action. α1D-AR was protected from desensitization by BMY-7378;while RS-100329 and prazosin partially mitigated desensitization. In another set of experiments, isolated aorta-derived smooth muscle cells were exposed to Ang II and α1-ARs proteins were evaluated. α1D-AR increased at 30 and 60 min post Ang II exposure, the α1A-AR diminished from 1 to 4 h, while α1B-AR remained unchanged over 24 h of Ang II exposure. Ang II induced an increase of α1D-AR at short times, and BMY-7378 protected α1D-AR from desensitization.

Angiotensin II administration in severe thrombocytopenia and chronic venous thrombosis:A case report

BACKGROUND The initial trials on angiotensin II(AT II)administration indicated a high incidence of thrombocytopenia and thrombosis,as well as a positive correlation between hyperreninemia and response to the medication.CASE SUMMARY We describe a case of a patient presenting with catecholamine resistant septic shock,thrombocytopenia,deep vein thrombosis,and normal renin concentration who responded immediately to AT II treatment.We observed no worsening of thrombocytopenia and no progression of thrombosis or additional thromboses during treatment.CONCLUSION Our case underscores the need for individualized assessment of patients for potential therapy with AT II.

MicroRNA-155 mediates endogenous angiotensin II type 1 receptor regulation:implications for innovative type 2 diabetes mellitus management

Type 2 diabetes mellitus(T2DM)is a lifelong condition and a threat to human health.Thorough understanding of its pathogenesis is acutely needed in order to devise innovative,preventative,and potentially curative pharmacological interventions.MicroRNAs(miRNA),are small,non-coding,one-stranded RNA molecules,that can target and silence around 60%of all human genes through translational repression.MiR-155 is an ancient,evolutionarily well-conserved miRNA,with distinct expression profiles and multifunctionality,and a target repertoire of over 241 genes involved in numerous physiological and pathological processes including hematopoietic lineage differentiation,immunity,inflammation,viral infections,cancer,cardiovascular conditions,and particularly diabetes mellitus.MiR-155 Levels are progressively reduced in aging,obesity,sarcopenia,and T2DM.Thus,the loss of coordinated repression of multiple miR-155 targets acting as negative regulators,such as C/EBPβ,HDAC4,and SOCS1 impacts insulin signaling,deteriorating glucose homeostasis,and causing insulin resistance(IR).Moreover,deranged regulation of the renin angiotensin aldosterone system(RAAS)through loss of Angiotensin II Type 1 receptor downregulation,and negated repression of ETS-1,results in unopposed detrimental Angiotensin II effects,further promoting IR.Finally,loss of BACH1 and SOCS1 repression abolishes cytoprotective,anti-oxidant,anti-apoptotic,and anti-inflam matory cellular pathways,and promotesβ-cell loss.In contrast to RAAS inhibitor treatments that further decrease already reduced miR-155 Levels,strategies to increase an ailing miR-155 production in T2DM,e.g.,the use of metformin,mineralocorticoid receptor blockers(spironolactone,eplerenone,finerenone),and verapamil,alone or in various combinations,represent current treatment options.In the future,direct tissue delivery of miRNA analogs is likely.

The Role for AVE0991 (MAS-Receptor Angiotensin II (1-7) Agonist) in Reducing Cisplatin-Induced Acute Kidney Injury on C57BL/6 Mice

Acute Kidney Injury (AKI) is a condition that causes nephrotoxicity in kidney tissues due to cisplatin-induced cancer treatments. Hence, it is proposed in this review that AVE0991 (a MAS-receptor Angiotensin II (1-7) agonist) may reduce cisplatin-induced acute kidney injury by promoting nitric oxide production.

Effects of chronic peripheral pretreatment with an angiotensin II type-1 receptor blocker on apoptosis-related molecules in rats with cerebral ischemia/reperfusion injury

Chronic systemic treatment with blockers of angiotensin II type-1 （AT1） receptors inhibits ischemia-induced apoptosis and reduces ischemic neuronal damage. However, the molecular mechanisms of AT1 receptor blockers in modulating neuronal apoptosis remain poorly understood. Pretreatment with irbesartan significantly suppressed cell apoptosis at 1-7 days following cerebral ischemia/reperfusion, increased levels of brain-derived neurotrophic factor, and elevated the ratios of Bcl-2/Bax and phosphorylated cyclic adenosine monophosphate response element-binding protein （pCREB）/CREB in the ischemic cortex at 1 day after reperfusion, as well as suppressing caspase-3 activation. Cerebral ischemia increased the mRNA expression of AT1 and AT2 receptors in the ischemic cortex, whereas irbesartan blocked this increase in AT1 expression but potentiated the expression of AT2. Therefore, this AT1 receptor blocker was neuroprotective by increasing the ratios of Bcl-2/Bax and pCREB/CREB, increasing brain-derived neurotrophic factor levels, inhibiting caspase-3 activation, and modulating AT receptor expression.

INTERLEUKIN 10 INHIBITS THE RAT VSMC PROLIFERATION AND COLLAGEN SECRETION STIMULATED BY ANGIOTENSIN II

Objective. To study the effect of interleukin 10 (IL- 10) on the angiotensin II (AngII) stimulated rat VSMC proliferation and collagen secretion, and furthermore, explore its mechanism. Methods. On cultured VSMC of rat, 3H- thymine (3H- TdR) and 3H- proline incorporations were used to evaluate the DNA and collagen synthesis, respectively. Western blot and immunoprecipitation were applied to assay the expression and activity of focal adhesion kinase (FAK), respectively. Results. IL- 10 (10－ 8～ 10－ 10g/ml) inhibited the increase of 3H- TdR and 3H- proline incorporation as well as FAK activity, which was induced by 10－ 7mol/L AngII (P< 0.05 or P< 0.01). IL- 10 also obviously downregulated the synthesis and secretion of collagen by AngII stimulated VSMC. But there was no difference in the protein expression of FAK among all the groups (P >0.05). Conclusion. IL- 10 antagonizes the VSMC proliferation and collagen synthesis by regulating FAK activity stimulated by AngII.

Spectrofluorimetric method for determination of some angiotensin II receptor antagonists

A simple, rapid, accurate and highly sensitive spectrofluorimetric method has been developed for determination of some angiotensin II receptor antagonists (AIIRA’s), namely Losartan potassium (Los-K), Irbesartan (Irb), Valsartan (Val) and Candesartan cilexetil (Cand) in pure forms as well as in their pharmaceutical dosage forms. All the variables affecting the relative fluorescence intensity (RFI) were studied and optimized. Under the optimum conditions, linear relationships with good correlation coefflcients (0.9982–0.9991) were obtained over the concentration range from 0.006 mg/mL to 1.7 mg/mL. Good accuracy and precision were successfully obtained for the analysis of tablets containing each drug alone or combined with hydrochlorothiazide (HCTZ) without interferences from the co-formulated HCTZ or the additives commonly present in tablets.

ROLE OF CALCINEURIN IN ANGIOTENSIN II- INDUCED CARDIAC MYOCYTE HYPERTROPHY OF RATS

The present study investigated the role of calcineurin in angiotensin II(AngII)- induced cardiac myocyte hypertrophy of rats. Method. The primary cardiac myocytes were cultured under the standard conditions. The calcineurin activity in AngII- treated cardiomyocytes was tested by using PNPP;protein synethsis rate was assessed by 3H- leucine incorporation; atrial natriuretic factor(ANF) mRNA level was determined by Northern blot analysis. Cell viability was estimated by lactate dehydrogenase(LDH) levels in cultured medium and by dyed cell numbers. Result. After stimulation of 10,100 and 1 000nmol/L of AngII, calcineurin activities in the cardiomyocytes were increased by 13％ ,57％ (P Conclusion. During AngII- induced cardiac myocyte hypertrophy, calcineurin signal pathway is activated, and inhibition of the pathway can attenuate AngII- induced cardiac myocyte hypertrophy, which suggests that the calcineurin signal pathway may play an important role in AngII- induced myocardial hypertrophy of rats.

Effect of gestational protein restriction on left ventricle hypertrophy and heart angiotensin II signaling pathway in adult offspring rats

Maternal protein restriction may be a risk factor for cardiovascular disorders in adulthood. The RAS (renin-angiotensin-system) plays a pivotal role in cardiac remodeling. Components of the RAS, including angiotensin II (AngII) and its receptors type 1 (AT1R) and 2 (AT2R) are expressed in the heart. This study investigates whether gestational protein restriction alters the expression and localization of AT1R and AT2R and RAS signaling pathway proteins in parallel with left ventricle hypertrophy and systemic hypertension in male offspring. Dams were kept on normal (NP, 17% protein) or low (LP, 6% protein) protein diet during pregnancy. Systolic blood pressure (SBP) of male offspring was measured from the 8th to 16th week and left ventricles of 16-wk-old rats were processed for histology, morphometric, immunoblotting and immunohistochemistry. LP offspring showed a significant reduction in birth body weight and SBP increased significantly from the 8th week. Left ventricle mass and cardiomyocytes area were also significantly higher in LP animals. Widespread perivascular fibrosis was not detected in the heart tissue. Analysis by immunoblotting and immunohistochemistry demonstrated a significant enhance in cardiomyocyte expression of AT1R and ERK1 in LP offspring. Expression of PI3K in LP was significantly reduced in cardiomyocytes and in the intramural coronary wall, while AT2R expression was unchanged in the NP group. We also found reduced LP expression of JAK2 and STAT3. In conclusion, our data also suggest that changes in the RAS may play a role in the ventricular growth through upregulation of the AT1-mediated ERK1/2 response, despite unchanged AT2R expression.

Involvement of Angiotensin II Type 1 Receptor and Calcium Channel in Vascular Remodeling and Endothelial Dysfunction in Rats with Pressure Overload

Vascular remodeling is an adaptive response to various stimuli,including mechanical forces,inflammatory cy tokines and hormones.In the present study,we investigated the role of angiotensinII type 1 receptor(ATIR)and calcium channel in carotid artery remodeling in response to increased biomechanical forces by using the transverse aortic constriction(TAC)rat model.TAC was induced on ten week-old male Sprague Dawley rats and these models were treated with ATIR blocker olmesartan(1 mg/kg/day)or/and calcium channel blocker(CCB)amlodipine(0.5 mgkgday)for 14 days.After the treatment,the right common carotid artery proximal to the band(RCCA-B)was collected for further assay.Results showed that olmesartan,but not amlodipine,significantly prevented TAC-induced adventitial hyperplasia.Similarly,olmesartan,but not amlodipine,significantly prevented vascular inflammation,as indicated by increased tumor necrosis factor a(TNF-a)and increased p65 phosphorylation,an indicator of nuclear factor K-light-chain-enhancer of activated B cells(NFkB)activation in RCCA-B.In contrast,both olmesartan and amlodipine reversed the decreased expression of endothelial nitric oxidase synthase(eNOS)and improved endothelium-dependent vasodilation,whereas combination of olmesartan and amlodipine showed no further synergistic protective effects.These results suggest that AT1R was involved in vascular remodeling and inflammation in response to pressure overload,whereas ATIR and subsequent calcium channel were involved in endothelial dysfunction.

EFFECT OF ANGIOTENSIN II RECEPTOR ANTAGONIST AND ENDOTHELIN RECEPTOR ANTAGONIST ON NITROGLYCERIN TOLERANCE IN RATS

Objective. To investigate whether angiotensin II receptor antagonist and endothelin receptor antagonist can improve the nitroglycerin (Nit) tolerance in vivo. Methods. Twenty- four rats were divided into 4 groups (n=6,each): Control group, Nitroglycerin (Nit) group, Nit＋ bosentan group and Nit＋ losartan group. Nitroglycerin tolerance was induced by 2- day treatment of nitroglycerin patch (0.05 mg/h). AngiotensinⅡ receptor antagonist losartan ( 10 mg· kg－ 1· d－ 1 ) and endothelin receptor antagonist bosentan ( 100 mg· kg－ 1· d－ 1 ) were given by gavage for 2 days respectively. Results. The least hypotensive response to sodium nitroprusside (SNP) was observed in Nit group . The effective percentages of hypotensive response to SNP were increased in both Nit＋ losartan group and Nit＋ bosentan group compared with Nit group [(31.95± 4.45 )％ vs (21.00± 3.69 )％ , P< 0.01 and (33.18± 6.16 )％ vs (21.00± 3.69 )％ , P< 0.01 ,respectively]. The maximal vessel relaxation induced by SNP was the same in 4 different groups but the highest EC50 (concentration which produces 50％ of the maximal response to SNP) was found in tolerant group[(34± 10) nmol/ L,P < 0.01 .The ET- 1 amounts in plasma and vascular tissue were markedly increased by 54％ and 60％ in Nit group compared with those in control group(P< 0.01).The ET- 1 amounts in plasma and vascular tissue were decreased by 30％ and 37％ in Nit＋ losartan group compared with those in Nit group (P< 0.01). Conclusion. Endothelin receptor antagonist and angiotensinⅡ receptor antagonist could prevent against the Nit tolerance .

Differential Effects of Angiotensin II on Intra-Renal Hemodynamics in Rats;Contribution of Prostanoids, NO and K⁺Channels

Many agents are known to cause qualitative and quantitative differences in intrarenal blood flow. This study tested the hypothesis that angiotensin II (AII) evokes a differential effect on cortical (CBF) and medullary blood flow (MBF) and that AT2 receptor mediates AII-induced increase in renal MBF by mechanisms related to nitric oxide (NO) and prostanoids. AII (100, 300 and 1000 ng/kg/min) increased mean arterial blood pressure (MABP) by 24% ± 7% (p G nitro-L-arginine (L-NNA), an inhibitor of NO synthase (100 mg/L in drinking water) enhanced AII effects on MABP (169 ± 75, p ATP channel blocker, did not affect intra-renal hemodynamics elicited by AII. Blockade of AT2 receptors with PD123319 (50 μg/kg/min) did not change basal or AII-induced changes MABP or CBF but blunted AII-induced increase in MBF by 60% ± 11 % (p 2 receptor agonist, elicited a reduction in MABP and increases in CBF and MBF that were abolished or attenuated by PD123319. These findings demonstrate that AII elicited differential changes in intrarenal blood flow;an AT1-mediated reduction in CBF but an AT2-mediated increase in MBF. The AT2 receptor-mediated increase in MBF involves guanylase cyclase, NO and dilator prostanoids but not KATP channels.

Antagonism of Angiotensin II AT1 Receptor and Silencing of CD44 Gene Expression Inhibit Cardiac Fibroblast Activation via Modulating TGF-<i>β</i>1/Smad Signaling Pathway

Angiotensin II (Ang II) is known to elicit cardiac fibrosis by activating the AT1 receptor and CD44 expression in the in vivo model. However, the cellular/molecular mechanisms underlying cardiac fibrosis are still not well understood. This study examines the roles of the AT1 receptor and CD44 gene expression in collagen synthesis through Ang II stimulated cardiac fibroblasts. Fibroblasts were isolated from the neonatal rat hearts;the activation of fibroblasts was evaluated using the assays of cell viability and migration, and silencing of CD44 gene expression was conducted with small interfering RNA (siRNA). Results showed that Ang II significantly increases the cell proliferation and migration in a dose-dependent manner. Upon activation, the protein levels of TGF-β1, Smad2, Smad4 and collagen I were significantly increased (all p < 0.05 vs. unstimulated cells), but these changes were significantly downregulated by the AT1 receptor blocker, telmisartan (all p < 0.05 vs. Ang II activated cells). Furthermore, mRNA and protein level of CD44 were upregulated, and there was a linear correlation between CD44 and TGF-β1 as demonstrated by Pearson correlation analysis (r = 0.955, p < 0.01). Gene transfection of fibroblasts with Ad-CD44 siRNA, as evidenced by low levels of CD44 mRNA and protein, significantly reduced the production of collagen I. In summary, these results indicate that the proliferation, migration and collagen production from Ang II activated cardiac fibroblasts are potentially mediated by the AT1 receptor and CD44. Such a signaling mechanism could be crucial for the production of collagen and the development of tissue fibrosis in the heart.

Polymyxin B Alleviates Angiotensin II-Induced Stress Fiber Formation and Cellular Hypertrophy

Polymyxin B is widely used antibiotic in the clinic for resistant Gram-negative infections. In addition, polymyxin B-immobilized hemoperfusion cartridge has been used for endotoxin removal therapy in patients with septic shock. The aim of this study was to investigate the anti-fibrotic and anti-cellular hypertrophic effects of polymyxin B, and further to explore its possible mechanism. Polymyxin B (3, 10 μM) significantly inhibited stress fiber formation induced by angiotensin II (Ang II) in rat heart-derived H9c2 cells. Furthermore, polymyxin B (1 - 10 μM) showed a potent inhibitory effect on Ang II-induced cellular hypertrophy in H9c2 cells. Under the mechanism study, the inhibitory activities of polymyxin B against kinases involved in cellular hypertrophy such as AKT1, CAMK, GRK5, GSK3β, MLCK, PKC, PKD2, AMPK, ROCK2, p70S6K, SGK1were evaluated. Polymyxin B possesses a potent G protein related kinase 5 (GKR5) inhibitory activity with IC50 value of 1.1 μM, and has an ATP non-competitive inhibitory mode. Taken together, these results indicate that polymyxin B alleviates Ang II-induced stress fiber formation and cellular hypertrophy, and propose that one mechanism underlying these effects involves inhibition of the GRK5 pathway.

The Significance of Angiotensin Converting Enzyme Inhibitor or Angiotensin II Receptor Blocker Use in Sudden Cardiac Death

Objectives: To investigate the relationship between the use of angiotensin converting enzyme (ACE) inhibitor or angiotensin II receptor blocker (ARB) and hyperkalemia in patients diagnosed with sudden cardiac death. Methods: We examined oral ACE inhibitor or ARB use among cardiopulmonary arrest patients brought by ambulance to our emergency room during a 5-year period from January 2012 to December 2016. The cause of death was determined to be sudden cardiac death, despite temporary return of spontaneous circulation after starting cardiopulmonary resuscitation. Subjects were dichotomized into 2 groups, those taking and those not taking an ACE inhibitor or ARB. Variables determined retrospectively included serum potassium, estimated glomerular filtration rate as an index of kidney function and time from cardiopulmonary arrest to return of spontaneous circulation. The Mann-Whitney U-test was used to compare continuous data, and the chi-square test to compare categorical data between groups. The results are expressed as the median plus range. Statistical significance was assumed at p Results: Thirty-five patients met the inclusion criteria. The mean age was 77.1 years (range, 35 - 93 years), and there were 26 males and 9 females. Eleven subjects were ACE inhibitor or ARB users, and 24 were non-users. The serum potassium level was significantly higher in users than non-users (median, 6.2 mEq/L (range, 4.5 - 10.0) vs. 5.2 mEq/L (range, 3.6 - 8.3);p = 0.001). The estimated glomerular filtration rate was significantly lower in users than non-users (median, 25.1 mL/min/1.73 m2 (range, 4.6 - 60.3) vs. 46.9 mL/min/1.73 m2 (range, 19.8 - 97.1);p = 0.009). There was no significant difference in time from cardiopulmonary arrest to return of spontaneous circulation between the 2 groups (median, 24 minutes (range, 3 - 111) vs. 29 minutes (range, 10 - 54);p = 0.355). Conclusion: It is possible that hyperkalemia induced by ACE inhibitor or ARB use is a cause of sudden cardiac death, especially in patients with chronic kidney disease.

Angiotensin-converting enzyme 2 alleviates liver fibrosis through the renin-angiotensin system

The present letter to the editor is related to the study titled‘Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells’.Angiotensin-converting enzyme 2 can alleviate liver fibrosis by regulating autophagy of hepatic stellate cells and affecting the renin-angiotensin system.

Protective Effect and Mechanism of Kuntai Capsule on Angiotensin II-Induced Hypertension in Ovariectomized Rats

Objective To explore the protective effect and mechanism of Kuntai(KT)Capsule on angiotensin II(Ang II)-induced hypertension in ovariectomized(OVX)rats.Methods Fifty-four rats were randomly divided into 6 groups according to a random number table,9 in each group:control,OVX sham+Ang II,OVX,OVX+Ang II,OVX+Ang II+E2,and OVX+Ang II+KT.OVX rats model was constructed by retroperitoneal bilateral ovariectomy.After 4 weeks of pretreatment with KT Capsule[0.8 g/(kg·d)and 17-β-estradiol(E2,1.2 mg/(kg·d)]respectively,Ang II was injected into a micro-osmotic pump with a syringe to establish a hypertensive rat model.Blood pressure of rat tail artery was measured in a wake state of rats using a non-invasive sphygmomanometer.Blood pressure changes were compared between the intervention groups(OVX+Ang II+KT,OVX+Ang II+E2)and the negative control group(OVX+Ang II).Serum malondialdehyde(MDA)level and superoxide dismutase(SOD)activity were detected respectively.The expressions of oxidative stress-related protein superoxide dismutase2(SOD2)and anti-thioredoxin(TRX),autophagy marker protein[beclin1,light chain(LC)3 II/I ratio and autophagy canonical pathway protein phosphatidylinositol 3-kinase(PI3K)/serine/threonine kinase(AKT)-mammalian target of rapamycin(mTOR)]were evaluated by Western blotting.Results Compared with the OVX+Ang II group,the systolic blood pressure of OVX+Ang II+KT group was significantly lowered(P<0.05)but not the diastolic blood pressure.Besides,SOD2 and TRX protein levels in mycardial tissues were significantly reduced in the OVX+Ang II+KT group compared with the OVX+Ang II group(P<0.05).Oxidative stress serum markers MDA and SOD were down-and up-regulated in the OVX+Ang II+KT group,respectively(P<0.05).Compared with OVX+Ang II group,the levels of cardiac proteins beclin-1 and LC3II/LC3 I in OVX+Ang II+KT group were also up-regulated(P<0.05),and the expression levels of p-PI3K,p-AKT and mTOR protein were down-regulated(P<0.05).Conclusion KT could protect blood pressure of Ang II-induced OVX rats by inhibiting oxidative stress and up-regulating protective autophagy.

Sulfur Dioxide Inhibits Extracellular Signal-regulated Kinase Signaling to Attenuate Vascular Smooth Muscle Cell Proliferation in Angiotensin II-induced Hypertensive Mice

Background： Clarifying the mechanisms underlying vascular smooth muscle cell （VSMC） proliferation is important for the prevention and treatment of vascular remodeling and the reverse of hyperplastic lesions. Previous research has shown that the gaseous signaling molecule sulfur dioxide （SO2） inhibits VSMC proliferation, but the mechanism for the inhibition of the angiotensin Ⅱ （Angll）-induced VSMC proliferation by SO, has not been fully elucidated. This study was designed to investigate if SO2 inhibited VSMC proliferation in mice with hypertension induced by Angll. Methods： Thirty-six male C57 mice were randomly divided into control, Angll, and Angll ＋ SO2 groups. Mice in Angll group and Angl I ＋ SO2 group received a capsule-type Angll pump implanted under the skin of the back at a slow-release dose of 1000 ng-kg^-1min In addition, mice in Angll ＋ SO2 received intraperitoneal injections of SO., donor. Arterial blood pressure of tail artery was determined. The thickness of the aorta was measured by elastic fiber staining, and proliferating cell nuclear antigen （PCNA） and phosphorylated-extracellular signal-regulated kinase （P-ERK） were detected in aortic tissues. The concentration of SO~ in serum and aortic tissue homogenate supernatant was measured using high-performance liquid chromatography with fluorescence determination. In the in vio＇o study, VSMC of A7R5 cell lines was divided into six groups： control, Angll, Angll ＋ SO2 PD98059 （an inhibitor of ERK phosphorylation）, Angll ＋ PD98059, and Angll ＋ SO, ＋ PD98059. Expression of PCNA, ERK, and P-ERK was determined by Western blotting. Results： In animal experiment, compared with the control group, Angll markedly increased blood pressure （P 〈 0.01 ） and thickened the aortic wall in mice （P 〈 0.05） with an increase in the expression of PCNA （P 〈 0.05）. SO2 however, reduced the systemic hypertension and the wall thickness induced by AnglI （P 〈 0.05）. It inhibited the increased expression of PCNA and P-ERK induced by AnglI （P 〈 0.05）. In cell experiment, PD98059, an ERK phosphorylation inhibitor, blocked the inhibitory effect of SO, on VSMC proliferation （P 〈 0.05）. Conclusions： ERK signaling is involved in the mechanisms by which SO, inhibits VSMC proliferation in Angll-induced hypertensive mice via ERK signaling.