CG200745 is a novel inhibitor of histone deacetylases (HDACs), initially developed for treatment of various hematological and solid cancers. Because it is water-soluble, it can be administered orally. We hypothesized that the HDAC inhibitor, CG200745, attenuates cardiac hypertrophy and fibrosis in deoxycorticosterone acetate (DOCA)-induced hypertensive rats. For establishment of hypertension, 40 mg/kg of DOCA was subcutaneously injected four times weekly into Sprague-Dawley rats. All the rats used in this study including those in the sham group had been unilaterally nephrectomized and allowed free access to drinking water containing 1% NaCl. Systolic blood pressure was measured by the tail-cuff method. Blood chemistry including sodium, potassium, glucose, triglyceride, and cholesterol levels was analyzed. Sections of the heart were visualized after trichrome and hematoxylin and eosin stain. The expression of hypertrophic genes such as atrial natriuretic peptide A (Nppa) and atrial natriuretic peptide B (Nppb) in addition to fibrotic genes such as Collagen-1, Collagen-3, connective tissue growth factor (Ctgf), and Fibronectin were measured by quantitative real-time PCR (qRT-PCR). Injection of DOCA increased systolic blood pressure, heart weight, and cardiac fibrosis, which was attenuated by CG200745. Neither DOCA nor CG200745 affected body weight, vascular contraction and relaxation responses, and blood chemistry. Injection of DOCA increased expression of both hypertrophic and fibrotic genes, which was abrogated by CG200745. These results indicate that CG200745 attenuates cardiac hypertrophy and fibrosis in DOCA-induced hypertensive rats.
Animals ; Blood Pressure ; Body Weight ; Cardiomegaly* ; Chemistry ; Cholesterol ; Connective Tissue Growth Factor ; Desoxycorticosterone ; Desoxycorticosterone Acetate ; Drinking Water ; Eosine Yellowish-(YS) ; Fibronectins ; Fibrosis* ; Glucose ; Heart ; Hematoxylin ; Histone Deacetylase Inhibitors* ; Histone Deacetylases* ; Histones* ; Hypertension ; Methods ; Potassium ; Rats* ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Relaxation ; Sodium ; Triglycerides

OBJECTIVETo investigate whether brain reactive oxygen species mediate sympathoexcitation and arterial pressure elevation in DOCA-salt hypertensive rats.

METHODSDOCA-salt hypertensive model was established in male SD rats by subcutaneous injection of DOCA after uninephrectomy and drinking 1% NaCl solution for 4 weeks. The baseline mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded in the rats under mild anesthesia, and MAP changes following intravenous hexamethonium injection were observed. The responses of MAP, HR and RSNA to intracerebroventricular administration of tempol (20 µmol/L in 10 µl) were evaluated; plasma NE level was measured with ELISA, and ROS level and NAD(P)H oxidase activity in the hypothalamus were detected using chemiluminescence assay.

RESULTSMAP and plasma NE levels were significantly increased in DOCA-salt rats as compared with those in the control group (P<0.01). In DOCA-salt hypertensive rats, intravenous hexamethonium injection induced a blood pressure reduction 240% of that in control rats, and significantly increased the levels of superoxide anion and NAD(P)H oxidase activity in the hypothalamus. Intracerebroventricular microinjection of tempol also resulted in more significant changes of MAP, HR and RSNA in DOCA-salt rats than in the control group (P<0.01).

CONCLUSIONSympathoexcitation due to increased NAD(P)H oxidase-derived ROS levels in the hypothalamus may mediate arterial pressure elevation in DOCA-salt hypertensive rats.

Animals ; Antioxidants ; Arterial Pressure ; Blood Pressure ; Brain ; metabolism ; Cyclic N-Oxides ; pharmacology ; Desoxycorticosterone ; Desoxycorticosterone Acetate ; Disease Models, Animal ; Heart Rate ; Hypertension ; Kidney ; innervation ; Male ; NADPH Oxidases ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; metabolism ; Sodium Chloride ; Spin Labels ; Superoxides ; metabolism ; Sympathetic Nervous System

BACKGROUND: The present study was designed to evaluate the possible renoprotective effects of tamoxifen in deoxycorticosterone acetate (DOCA)-salt hypertensive (DSH) rats and its role in inflammation and fibrosis in the kidney. METHODS: Male Sprague-Dawley rats, weighing 180 to 200 g, were used. All rats underwent unilateral nephrectomy. One week later, one group of rats (n = 8) was implanted with DOCA strips (200 mg/kg) and another group of rats (n = 8) was implanted with DOCA strips with co-treated with tamoxifen (10 mg/kg) through gavage feeding. Rats that did not implanted DOCA strips served as controls (n = 6). Two weeks later, the systolic blood pressure (SBP) was measured by tail-cuff method. The protein expression of transforming growth factor-beta (TGF-beta), Smad, alpha-smooth muscle actin (alpha-SMA), E-cadherin, ED-1, cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) was determined in the kidney by immunoblotting. The mRNA expression of tumor necrosis factor-alpha (TNF-alpha), monocyte chemotactic protein-1 (MCP-1), and vascular cell adhesion molecule-1 (VCAM-1) was determined by real-time polymerase chain reaction. RESULTS: In DSH rats, SBP was increased, which was not affected by tamoxifen treatment. Serum creatinine level was comparable in DSH rats compared with controls, which was not affected by tamoxifen treatment. In DSH rats, the protein expression of TGF-beta, Smad 2/3, Smad 4, alpha-SMA, ED-1, COX-2, iNOS was increased compared with controls, and these changes were attenuated by tamoxifen treatment except that of TGF-beta. The mRNA expression of TNF-alpha, MCP-1, and VCAM-1 was increased, and expression of MCP-1 and VCAM-1 was counteracted by tamoxifen treatment. CONCLUSIONS: Tamoxifen is effective in preventing the progression of nephropathy in DSH rats, the mechanism of which is associated with anti-inflammation and anti-fibrotic effects.
Actins ; Animals ; Blood Pressure ; Cadherins ; Chemokine CCL2 ; Creatinine ; Cyclooxygenase 2 ; Desoxycorticosterone Acetate ; Desoxycorticosterone* ; Fibrosis ; Humans ; Hypertension ; Immunoblotting ; Inflammation ; Kidney ; Male ; Methods ; Muscles ; Nephrectomy ; Nitric Oxide Synthase Type II ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Tamoxifen* ; Transforming Growth Factor beta ; Tumor Necrosis Factor-alpha ; Vascular Cell Adhesion Molecule-1

The present study investigated the changes that occurred in the mammalian target of rapamycin (mTOR) signaling pathway in the kidney as a result of deoxycorticosterone acetate (DOCA)-salt hypertension. Rats were implanted with DOCA strips (200 mg/kg) 1 week after unilateral nephrectomy and were then supplied with 0.9% saline to drink. Four weeks after DOCA implantation, systolic blood pressure (SBP) was measured by use of the tail-cuff method. The expression levels of phosphorylated phosphatidylinositol-3-kinase (PI3K), Akt, and mTOR, as well as the protein expression levels of ED-1 and cyclooxygenase-2 (COX-2), transforming growth factor-beta1 (TGF-beta1), alpha-smooth muscle actin (SMA), caspase-3, Bax, and Bcl-2, were then examined in the kidney by semiquantitative immunoblotting. DOCA-salt hypertensive rats were found to have significantly increased SBP as well as an increased kidney weight-to-body weight ratio. Moreover, the phosphorylation of PI3K, Akt, and mTOR was increased in the kidney of DOCA-salt hypertensive rats compared with the control, as was the protein expression of ED-1, COX-2, TGF-beta1, and alpha-SMA. The expression levels of caspase-3 and Bax were increased significantly, whereas Bcl-2 expression was decreased. In conclusion, the phosphorylation of PI3K/Akt/mTOR was increased in the kidney of DOCA-salt hypertensive rats.
Actins ; Animals ; Blood Pressure ; Caspase 3 ; Cyclooxygenase 2 ; Desoxycorticosterone ; Hypertension ; Immunoblotting ; Kidney ; Muscles ; Nephrectomy ; Phosphorylation ; Rats ; Sirolimus ; Transforming Growth Factor beta1

Renal sodium and water reabsorption occurs through epithelial sodium transporters and aquaporin (AQP) water channels in various segments of tubules. We have demonstrated altered regulation of these transporters and channels in various pathophysiological conditions. In nephrotic syndrome and liver cirrhosis, expression of epithelial sodium channels (ENaC) was increased in the late distal convoluted tubule, connecting tubule, and collecting duct. In spontaneously hypertensive rats, the expression of Na,K-ATPase as well as that of ENaC was increased. In contrast, AQP1-3 and sodium transporters was decreased in the kidney from deoxycorticosterone acetate-salt hypertension. In two-kidney, one clip hypertension, the expression of Na,K-ATPase, NHE3, NKCC2 and ENaC subunits was decreased in the clipped kidney while remained unchanged in the contralateral kidney. We have also shown an increased activity of renal atrial natriuretic peptide system in postobstructive natriuresis/ diuresis. In acute kidney injury (cisplatin-, gentamicin- and ischemia/reperfusion-induced), the expression of Na,K-ATPase, NHE3, NKCC2 and AQP1-3 was decreased. The altered regulation of sodium transporters and AQP may be causally related with various kidney diseases and hypertension.
Acute Kidney Injury ; Aquaporins ; Desoxycorticosterone ; Diuresis ; Epithelial Sodium Channels ; Hypertension ; Kidney ; Kidney Diseases ; Liver Cirrhosis ; Nephrotic Syndrome ; Rats, Inbred SHR ; Sodium

Renal sodium and water reabsorption occurs through epithelial sodium transporters and aquaporin (AQP) water channels in various segments of tubules. We have demonstrated altered regulation of these transporters and channels in various pathophysiological conditions. In nephrotic syndrome and liver cirrhosis, expression of epithelial sodium channels (ENaC) was increased in the late distal convoluted tubule, connecting tubule, and collecting duct. In spontaneously hypertensive rats, the expression of Na,K-ATPase as well as that of ENaC was increased. In contrast, AQP1-3 and sodium transporters was decreased in the kidney from deoxycorticosterone acetate-salt hypertension. In two-kidney, one clip hypertension, the expression of Na,K-ATPase, NHE3, NKCC2 and ENaC subunits was decreased in the clipped kidney while remained unchanged in the contralateral kidney. We have also shown an increased activity of renal atrial natriuretic peptide system in postobstructive natriuresis/ diuresis. In acute kidney injury (cisplatin-, gentamicin- and ischemia/reperfusion-induced), the expression of Na,K-ATPase, NHE3, NKCC2 and AQP1-3 was decreased. The altered regulation of sodium transporters and AQP may be causally related with various kidney diseases and hypertension.
Acute Kidney Injury ; Aquaporins ; Desoxycorticosterone ; Diuresis ; Epithelial Sodium Channels ; Hypertension ; Kidney ; Kidney Diseases ; Liver Cirrhosis ; Nephrotic Syndrome ; Rats, Inbred SHR ; Sodium

PURPOSE: Baroreceptor reflex regulation has been shown to reset towards a higher blood pressure level. This study was designed to assess alterations of chronotropic baroreflexes in two-kidney, one clip (2K1C) and deoxycorticosterone acetate (DOCA)-salt hypertensive rats. METHODS: Arterial pressure and heart rate (HR) were monitored continuously during intravenous infusions of phenylephrine or sodium nitroprusside. Ensuing reflex HR responses during each drug infusion were determined in two ways: (a) at 10 s intervals (time analysis), and (b) with every 10 mmHg change in pressure (pressure analysis). RESULTS: Both pressor and depressor responses produced by phenylephrine or sodium nitroprusside were comparable between normotensive and hypertensive rats. Both reflex tachycardia and bradycardia were attenuated in 2K1C hypertensive rats as compared with normotensive rats, whereas no significant differences were shown in DOCA-salt hypertensive rats. CONCLUSION: These results indicate that chronotropic baroreflexes are impaired in 2K1C hypertensive rats, but not in DOCA-salt hypertensive rats.
Animals ; Arterial Pressure ; Baroreflex ; Blood Pressure ; Bradycardia ; Desoxycorticosterone ; Dihydrotachysterol ; Heart Rate ; Hypertension ; Infusions, Intravenous ; Nitroprusside ; Phenylephrine ; Rats ; Reflex ; Tachycardia

The deoxycorticosterone acetate (DOCA)-salt rat is known as a model of volume dependent hypertension and characterized by increased cardiac endothelin-1 (ET-1) content. Recently, it has been reported that rosiglitazone (RGT), a peroxisome proliferator-activated subtype gamma receptor agonist, shows blood pressure lowering effect. We investigated whether DOCA-salt hypertension is associated with altered expression of heat shock proteins (HSP) and ET-1 in the heart, aorta, and kidney, and whether RGT changes HSP expression and ET-1 in association with its blood pressure lowering effect. Two weeks after the silastic DOCA (200 mg/kg) strips implantation, DOCA-salt rats were randomly divided to receive control diet with or without RGT (10 mg/kg/day) for another 2 weeks. The mRNA expression of ET-1 was determined by real time polymerase chain reaction. The expression of HSP was determined by semiquantitative immunoblotting. In DOCA-salt rats, systolic blood pressure was markedly increased, while creatinine clearance decreased. RGT treatment attenuated high blood pressure and decreased creatinine clearance in DOCA-salt rats. The mRNA expression of ET-1 was increased in DOCA-salt rats compared to controls, which was counteracted by RGT treatment. The protein expression of HSP70, HSP32, and HSP25 was increased in the kidney and heart in DOCA-salt rats, which was attenuated by RGT treatment in the kidney, but not in the heart. In conclusion, increased expression of ET-1 may play a role in the pathogenesis of hypertension in DOCA-salt rats, which was counteracted by the treatment of RGT. Up-regulation of HSP70, HSP32, and HSP25 in the kidney and heart may play a role in organ protection against a variety of stresses.
Animals ; Aorta ; Blood Pressure ; Creatinine ; Desoxycorticosterone ; Diet ; Dimethylpolysiloxanes ; Endothelin-1 ; Endothelins ; Heart ; Heat-Shock Proteins ; Hot Temperature ; Hypertension ; Immunoblotting ; Kidney ; Peroxisomes ; Rats ; Real-Time Polymerase Chain Reaction ; RNA, Messenger ; Thiazolidinediones ; Up-Regulation

The present study was aimed at investigating the role of type II 11beta-hydroxysteroid dehydrogenase (IIbeta- HSD II) in the development of hypertension. Two-kidney, one-clip (2K1C), deoxycorticosterone acetate (DOCA)/salt, or NG-nitro-L-arginine methyl ester (L-NAME) hypertension was induced in male Sprague- Dawley rats. Four weeks later, the expression of 11beta-HSD II mRNA was determined in the kidney by Northern blot analysis. The plasma level of aldosterone was measured by radioimmunoassay. In 2K1C hypertension, the expression of 11beta-HSD II was decreased in the clipped kidney and increased in the non-clipped kidney. The expression was increased in the remnant kidney of DOCA/salt hypertension, while decreased in the kidneys of L-NAME hypertension. The plasma level of aldosterone was increased, decreased, and remained unchanged in 2K1C, DOCA/salt, and L-NAME hypertension, respectively. The down-regulation of 11beta-HSD II may contribute to the sodium retention, thereby increasing the blood pressure in 2K1C and L-NAME hypertension. On the contrary, the up-regulation in DOCA/salt hypertension may play a compensatory role to dissipate the sodium retention.
11-beta-Hydroxysteroid Dehydrogenases* ; Aldosterone ; Animals ; Blood Pressure ; Blotting, Northern ; Desoxycorticosterone ; Down-Regulation ; Humans ; Hypertension* ; Kidney* ; Male ; NG-Nitroarginine Methyl Ester ; Plasma ; Radioimmunoassay ; Rats* ; RNA, Messenger ; Sodium ; Up-Regulation

There are growing evidences suggesting a pivotal role of oxidative stress in the pathophysiology of preeclampsia. We investigated oxidative stress in the rat model of preeclampsia, and in clinical cases. Pregnant female rats were injected intraperitoneally with deoxycorticosterone acetate (DOCA) and given 0.9% saline as drinking water during their pregnancy. We assessed plasma F2-isoprostane (8-iso-PGF2alpha) and malondialdehyde (MDA) in a rat model, and the same markers in the plasma of maternal blood and fetal cord blood in pregnant women with preclampsia. Blood samples from the umbilical arteries and veins were collected separately. The concentrations of MDA were increased in the preeclampsia groups of animal and humans, compared with the control group; it was significantly increased in the umbilical artery and vein of the preeclampsia group. The concentrations of F2-isoprostane were elevated in the preeclampsia groups of animal and humans, compared with the control group, and the increase in F2-isoprostane concentration was prominent in the umbilical vein than umbilical artery of the preeclampsia group. Therefore, it appears that the placenta has an important role in the pathophysiology of preeclampsia, and the F2-isoprostanes of the umbilical vein may serve as a relatively reliable marker for ischemic/hypoxic injury to the fetus during the perinatal period.
Animals ; Desoxycorticosterone ; Drinking Water ; F2-Isoprostanes ; Female ; Fetal Blood ; Fetus ; Humans ; Malondialdehyde ; Models, Animal* ; Oxidative Stress ; Placenta ; Plasma ; Pre-Eclampsia* ; Pregnancy ; Pregnant Women ; Rats* ; Umbilical Arteries ; Umbilical Veins ; Veins