Ventricular remodeling by Scutellarein treatment in spontaneously hypertensive rats

OBJECTIVE: To observe reversal of ventricular remodeling by the protein kinase C inhibitor Scutellarein in spontaneously hypertensive rats (SHRs). METHODS: Twelve SHRs were randomly divided into two groups. Scutellarein and saline (10 mg x kg(-1) x d(-1)) were given by intraperitoneal injection to two groups of rats separately. Systolic blood pressure (SBP) and ventricular weight index (LVW/BW, RVW/BW) were measured. A polarization microscope and an image analyzer system (IAS) were used to observe changes in cardiovascular structure and to count the content of cardiac muscle interstitial collagen. RESULTS: The pathologic changes in the left ventricle in the Scutellarein group rats (SHR(D)) improved to varying degrees, including hypertrophy of the cardiac muscle and collagen volume fraction. CONCLUSION: Scutellarein can reverse ventricular remodeling, improve myocardial stiffness and protect heart cardiac muscle.

Endothelin-1, an important mitogen of smooth muscle cells of spontaneously hypertensive rats

OBJECTIVE: To study the features of vascular smooth muscle cell (VSMC) proliferation induced by endothelin-1 (ET-1). METHODS: VSMCs of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were cultured and treated with ET-1. Basic fibroblast growth factor (bFGF) gene expression was measured using both Northern blot and an enzyme-linked immunoassay. RESULTS: ET-1 resulted in an increase in bFGF transcripts at 8 - 24 h; bFGF levels were significantly higher in VSMCs treated with ET-1 than in those not treated. However, VSMCs growth responses in SHR and WKY were different. Smooth muscle cells of SHR were hyper-responsive to ET-1. Maximal bFGF mRNA levels were elevated 3.5-fold at 4 h of stimulation in WKY and 8-fold at 8h in SHR4. Moreover, the proliferation of VSMCs induced by ET-1 was inhibited by antisense phosphorothioate oligodeoxynucleotides (10 micromol/L AS-bFGF) but not sense bFGF oligomers at the same concentrations, being reduced by 80% in SHR and 40% in WKY vs control, respectively. Furthermore, the effect of AS-bFGF oligomers on SHR SMC proliferation is significantly greater than on WKY SMC proliferation. CONCLUSION: ET-1 may be required for exaggerated vascular growth responses in SHR and bFGF may be involved.

Influence of Valsartan on myocardial apoptosis in spontaneously hypertensive rats

OBJECTIVE: To explore the pathogenic changes of myocardial apoptosis in heart hypertrophy during hypertension and evaluate the anti-apoptosis effect of Valsartan. METHODS: Thirty spontaneously hypertensive rats (SHRs) were divided into two groups: 15 treated with Valsartan (20 mg x kg(-1) x d(-1)) (SHR + Valsartan group), the others with placebo (SHR + placebo group), with 15 normal Wistar rats as control. Systolic blood pressure was measured by the tail-cuff method. The observation period was from 8 to 16 weeks of age. Cardiac apoptosis was evaluated by a Terminal Deoxynucleotidyl Transferase-Mediated dUTP-biotin Nick End Labeling (TUNEL) assay. RESULTS: Mean blood pressure values were 127 +/- 2 mm Hg in controls, 163 +/- 6 mm Hg in the SHR + Valsartan group and 193 +/- 7 mm Hg in the SHR + placebo group at 16 weeks of age, whereas the blood pressure in 8-week-old SHR and Wistar rats were 175 +/- 3 mm Hg and 125 +/- 5 mm Hg, respectively. The ratio of the heart weight over body weight declined in Wistar (3.07 +/- 0.03 mg/g) and SHR + Valsartan groups (3.22 +/- 0.19 mg/g) compared with the SHR + placebo group (4.02 +/- 0.31 mg/g) (P

Endothelin receptor antagonist combined with a calcium channel blocker attenuates renal injury in spontaneous hypertensive rats with diabetes

OBJECTIVE: To investigate the effects of the mixed endothelin receptor antagonist, bosentan, combined with the long-acting calcium channel blocker, amlodipine, compared to the angiotensin-converting enzyme inhibitor, cilazapril, on the progressive renal injury in spontaneous hypertensive rats (SHR) with diabetes. METHODS: Diabetic hypertensive rats (SHR-DM) were induced by streptozotozin injected in male SHR (7-week-old),and divided into an untreated and three treated groups: 1) cilazapril treated group; 2) bosentan+amlodipine treated group; and 3) amlodipine treated group. Wistar Kyoto rats (WKY) and SHR rats served as normotensive and hypertensive control, respectively. The mean arterial blood pressure, renal function, endothelin and angiotensin II levels as well as the protein expression of renal extracellular matrix components and transforming growth factor (TGF)-beta1 were determined at the end of the 4th week. RESULTS: Mean arterial blood pressure significantly increased in SHR and SHR-DM rats compared to WKY rats. All the therapies reduced the blood pressure to normal levels. However, the enhanced urinary protein excretion, the decreased creatinine clearance as well as the increased plasma and intrarenal endothelin and angiotens in II levels were found in the untreated SHR-DM and prevented by treatment with bosentan+amlodipine and cilazapril. Similarly, these two kinds of therapies in SHR-DM abolished the overexpression of renal TGF-beta1 by Western blot analysis and reduced the accumulation of collagen type IV, laminin and fibronectin proteins by an immunochemical approach. Amlodipine monotherapy had no detectable effects on the above parameters. CONCLUSION: Bosentan combined with amlodipine can offer similar renoprotective effects on that of cilazapril and may be a potent therapy to attenuate renal injury by reducing renal protein levels of TGF-beta1 in diabetes with a hypertensive state.

Mechanism and effect of Shijueming (Concha Haliotidis) on serum calcium in spontaneously hypertensive rats

OBJECTIVE： To observe the impact of Shijueming （Concha Haliotidis） on spontaneously hypertensive rats via blood pressure, serum calcium, vascular smooth muscle membrane L-type calcium channel α1 C subunit （CaL-α1C）, plasma membrane calci- um-ATPase （PMCA） mRNA expression, and the L-type calcium channel in vascular smooth muscle cells. METHODS： Twelve-week-old male rats with sponta- neous hypertension were divided into three groups： a Shijueming （Concha Haliotidis） group （group 1）, a nifedipine group （group 2）, and a dis- tilled water group （group 3）. All were given a four-week treatment. Blood pressure and dissocia- tive serum calcium were examined before treat- ment. Blood pressure was taken every week during treatment. Atomic absorption spectrometry was used to examine dissociative serum calcium. Re-verse transcription-polymerase chain reaction was used to examine the expression of CaL-α1C and PM- CA1 mRNA. The patch clamp technique was used to examine the electrophysiological characteristics of the vascular smooth muscle cell calcium chan- nels. RESULTS： After treatment, blood pressure of the Shijueming （Concha Halioticlis） group lowered but not significantly （P〉0.05）. Blood pressure of the nifedipine group lowered significantly （P〈0.05）. Blood pressure of the distilled water group re- mained high. The concentration of serum calcium in the Shijueming （Concha Haliotidis） and the dis- tilled water groups lowered （P〈0.05）. Expression of CaL-α1C mRNA in the nifedipine group decreased compared with the distilled water group （P〈0.01）. There was the decreasing trend in the Shijueming （Concha Haliotidis） group, but it was not statistically significant. Shijueming （Concha Haliotidis） also had effects on the expression of PMCA1 mRNA but with- out statistical significance. However, there was a significant decreasing effect on vascular smooth muscle cell Ica-L flow. CONCLUSION： This study indicated that Shijuem- ing （Concha Haliotidis） could increase serum calci- um and decrease blood pressure. It may work by in- fluencing calcium channels, expression of PMCA1 mRNA, and regulating ion calcium channels and calcium-ATPase.

Upregulation of the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor axis by a combination of Yinyanghuo(Herba Epimedii Brevicornus) and Cheqianzi(Semen Plantaginis) improves erectile function in spontaneously hypertensive rats

OBJECTIVE:To evaluate the effects of a combination of Yinyanghuo(Herba Epimedii Brevicornus)(HEB)and Cheqianzi(Semen Plantaginis)(SP)on erectile dysfunction caused by essential hypertension in spontaneously hypertensive rats(SHRs),and to elucidate the role of the angiotensin-converting enzyme 2-angiotensin-(1-7)-Mas receptor(ACE2/Ang[1-7]/Mas receptor)axis in this process.METHODS:A total of 24 SHRs were randomly assigned to three groups:SHR-control,low-dose(12.5 g/kg)and high-dose(25 g/kg)HEB+SP(HEBSP).Eight Wistar-Kyoto rats were used as normal controls.HEBSP was administered by oral gavage for 28 d.Erectile function was measured once a week using the Heaton test.After 4 weeks of treatment,the corpus cavernosum was harvested from each rat to measure nitric oxide(NO),nitric oxide synthase(e NOS)and Ang(1-7)levels,as well as ACE2,Mas receptor and neuronal nitric oxide synthase(n NOS)protein expression.RESULTS:After 4 weeks of treatment,HEBSP significantly increased erectile function in the treated group compared with SHR-control group(P<0.01).Additionally,HEBSP treatment significantly increased cavernosal levels of Ang(1-7),e NOS and NO.Moreover,HEBSP significantly elevated the expression levels of ACE2,Mas receptor and n NOS.These beneficial effects were elevated in the high-dose HEBSP group.CONCLUSION:HEBSP improved erectile function in SHRs by upregulating the ACE2/Ang(1-7)/Mas receptor axis,e NOS and n NOS pathways.