Function In Spontaneously Hypertensive Rats Research Articles

O96 NICD LACTYLATION OF NOTCH SIGNALING IMPROVES MICROVASCULATION RAREFACTION IN HYPERTENSION

Background and Objective: Microvascular rarefaction is a key pathophysiologic basis of hypertension-related cardiovascular disease. Exercise decreases blood pressure and promotes angiogenesis related to inhibition of NOTCH signaling. The activation of the NOTCH pathway depends on the transcriptional regulation of its intracellular active fragment NICD after nuclear translocation. The post-translational modification status of proteins plays a crucial role in the nuclear translocation effect of transcription factors. Lactylation is influenced by the level of lactate in the body. Exercise can promote glycolysis in endothelial cells, and increase intracellular lactate levels. Therefore, we explored whether the beneficial effects of Exercise were mediated by promoting NICD lactylation, inhibiting the NOTCH signaling, and promoting angiogenesis. Methods: To test our hypotheses, WKYs (normotensive rats) and SHRs (spontaneously hypertensive rats) were given exercise for 12 weeks. Blood pressure was determined by the tail-cuff method, and cardiac function was assessed by echocardiography. Using rats’ retina, gastrocnemius, and myocardium detected microvascular density. The expression levels of NOTCH signaling pathway related proteins and angiogenesis related factors were measured by Western Blotting. The level of lactate was measured by using a lactate assay kit. Protein modification omics was used to detect the modification types and levels of NICD in microvascular endothelial cells, followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to detect the lactylation sites of NICD in microvascular endothelial cells. Results: Exercise in SHRs resulted in reduced blood pressure and concentric hypertrophy. Exercise promoted angiogenesis and improved microcirculation rarefaction. Exercise also reduced the production of NOTCH pathway related proteins and increased the expression level of angiogenesis related factors. The lactate level increased after exercise, and the lactylation level of NICD increased. Conclusions: In summary, Exercise decreases hypertension and improves cardiac function in SHRs. Our research results indicated that exercise increases lactate production and induces NICD lactylation, thereby inhibiting the NOTCH signaling, upregulating the expression of angiogenic factors, promoting angiogenesis, and lowering blood pressure.

Transcriptome and proteome analyses reveal that upregulation of GSTM2 by allisartan improves cardiac remodeling and dysfunction in hypertensive rats.

Long-term hypertension can lead to hypertensive heart disease, which ultimately progresses to heart failure. As an angiotensin receptor blocker antihypertensive drug, allisartan can control blood pressure, and improve cardiac remodeling and cardiac dysfunction caused by hypertension. The aim of the present study was to investigate the protective effects of allisartan on the heart of spontaneously hypertensive rats (SHRs) and the underlying mechanisms. SHRs were used as an animal model of hypertensive heart disease and were treated with allisartan orally at a dose of 25 mg/kg/day. The blood pressure levels of the rats were continuously monitored, their body and heart weights were measured, and their cardiac structure and function were evaluated using echocardiography. Wheat germ agglutinin staining and Masson trichrome staining were employed to assess the morphology of the myocardial tissue. In addition, transcriptome and proteome analyses were performed using the Solexa/Illumina sequencing platform and tandem mass tag technology, respectively. Immunofluorescence co-localization was conducted to analyze Nrf2 nuclear translocation, and TUNEL was performed to detect the levels of cell apoptosis. The protein expression levels of pro-collagen I, collagen III, phosphorylated (p)-AKT, AKT, p-PI3K and PI3K, and the mRNA expression levels of Col1a1 and Col3a1 were determined by western blotting and reverse transcription-quantitative PCR, respectively. Allisartan lowered blood pressure, attenuated cardiac remodeling and improved cardiac function in SHRs. In addition, allisartan alleviated cardiomyocyte hypertrophy and cardiac fibrosis. Allisartan also significantly affected the 'pentose phosphate pathway', 'fatty acid elongation', 'valine, leucine and isoleucine degradation', 'glutathione metabolism', and 'amino sugar and nucleotide sugar metabolism' pathways in the hearts of SHRs, and upregulated the expression levels of GSTM2. Furthermore, allisartan activated the PI3K-AKT-Nrf2 signaling pathway and inhibited cardiomyocyte apoptosis. In conclusion, the present study demonstrated that allisartan can effectively control blood pressure in SHRs, and improves cardiac remodeling and cardiac dysfunction. Allisartan may also upregulate the expression levels of GSTM2 in the hearts of SHRs and significantly affect glutathione metabolism, as determined by transcriptome and proteome analyses. The cardioprotective effect of allisartan may be mediated through activation of the PI3K-AKT-Nrf2 signaling pathway, upregulation of GSTM2 expression and reduction of cardiomyocyte apoptosis in SHRs.

Abstract P3001: Regulation Of Perivascular Adipose Tissue By Follistatin In Hypertension

Follistatin lowers BP and improves resistance artery health in spontaneously hypertensive rats (SHR), a model of essential HTN. Functionally, follistatin improves smooth muscle contraction and endothelium-dependent relaxation. Structurally, increased medial collagen was inhibited. Vascular ROS were also reduced. Perivascular adipose tissue (PVAT) regulates vascular tone via release of vasoactive substances. Oxidative stress in PVAT, as in HTN, induces release of contractile agents. Transition from white to brown PVAT is associated with decreased risk of CVD. We analyze effects of follistatin on PVAT and its regulation of vessel function in SHR and normotensive Wistar Kyoto (WKY) rats. White and brown PVAT were dissected from treated rats; arteries were isolated from untreated donors. PVAT was introduced near strain-matched donor arteries and assessed for ROS levels and contractility using DHE and wire myography, respectively. In some vessels, endothelium was denuded to assess its contribution to contraction. Follistatin reduced ROS, hypercontractility, and improved relaxation in a PVAT-dependent manner. Brown PVAT induced significant anti-contractile and antioxidant effects. Elevated expression of adipose tissue browning markers and decreased adipocyte area with follistatin, support PVAT browning effects. Endothelium removal results in augmented vessel constriction, effects reduced by follistatin. Follistatin improves SHR smooth muscle tone in a PVAT-dependent manner, likely through the inhibition of vascular ROS and browning of PVAT. Future work will profile PVAT effects of follistatin through unbiased proteomic analysis. Although most vessels are surrounded by PVAT, studies of PVAT-vessel interaction in HTN are few. By characterizing PVAT dysfunction, we aim to outline specific PVAT-mediated pathways involved in lowering BP and improving vascular function and structure. Results will provide new insights into PVAT-targeted therapy for essential HTN, allowing potential translation of benefits to obesity and other diseases exhibiting PVAT dysfunction.

Acute exposure to chlorpyrifos differentially impacts survival and cardiovascular function of normotensive and hypertensive rats

Hypertension is the most important and well-known risk factor for cardiovascular disease (CVD). Recently, acute organophosphate (OP) poisoning has also been pointed as a CVD risk factor. Despite these evidence, no studies have contrasted the cardiovascular (CV) effects of OP poisoning under conditions of normotension and hypertension. We hypothesized that hypertensive rats would have a greater impairment of CV function after acute exposure to chlorpyrifos (CPF), an OP compound. 12-14 week-old male normotensive Wistar and Spontaneously Hypertensive rats (SHRs) were intraperitoneally (i.p.) injected with saline (NaCl 0.9%) or 20 mg.kg-1 of CPF, a previously shown sublethal dose in normotensive rats. 24-hour survival was recorded and through cannulation of the femoral artery and vein, we assessed blood pressure (BP) and heart rate (HR) recordings and chemically activated the Bezold-Jarisch Reflex (BJR), the Chemoreflex (CR), as well as assessed the cardiac autonomic tone (AUT). BJR was activated by phenylbiguanide (PBG; 1.5; 3; 6; 12; 24 μg/kg; i.v.) and the CR by potassium cyanide (KCN, 10, 20, 40 and 80 μg/ rat; i.v.) injections, while the AUT was assessed by pharmacological blockade with atenolol (4mg.kg-1, i.v) and atropine (2mg.kg-1, i.v). CPF acute exposure induced 33% mortality in SHR without leading to lethality in Wistar rats. CPF poisoning impaired the BJR hypotensive response in Wistar rats for all PBG doses tested (ΔDBP: - 33.83±4.88 vs. -14.16±2.68; -44.58±3.48 vs. -30.58±2.16; -66.16±2.50 vs. -36.16±2.54; -72.66±2.66 vs. -47.91±2.50; -78.66±2.35 vs.-61.58±2.40; p<0.05 Wistar saline vs Wistar CPF) and the bradycardic response at the dose of 6 and 12μg/kg, respectively (ΔHR: -268.66±14.77 vs. -216.66±11.11; -304.58±13.42 vs. -241.66±11.01; p<0.05 Wistar saline vs Wistar CPF), without affecting the SHR strain. No CPF-induced changes were observed for the CR and AUT between strains. Our findings show that, despite being sublethal in normotensive rats, CPF lead to mortality in hypertensive rats. However, contrary to our hypothesis, CPF poisoning did not further impaired CV function in SHR, but significantly worsen BJR function in Wistar rats. Despite not producing greater impairment in CV function, CPF poisoning leads to greater mortality under hypertension, which may impose a significant risk in individuals with this comorbidity. Aitken AV, was recipeint of Fapes Foundation scholarship. Minassa VS, Batista TJ were recipients of Capes Foundation scholarship. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Effects of hypertension and aging on brain function in spontaneously hypertensive rats: a longitudinal resting-state functional magnetic resonance imaging study.

To investigate the dynamic evolution of brain function under the comorbidities of hypertension and aging. Resting-state functional magnetic resonance imaging scans were longitudinally acquired at 10, 24, and 52weeks in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats. We computed the mean amplitude of low-frequency fluctuation (mALFF), mean regional homogeneity (mReHo), and functional connectivity (FC). There was no interaction between hypertension and aging on brain function. The main effect of aging reflects primarily the cumulative increase of brain activity, especially the increase of mALFF in amygdala and mReHo in cingulate cortex, accompanied by the decrease of brain activity. The main effect of hypertension reflects primarily decreased brain activity in default modal network, accompanied by increased brain activity. The main effect of aging shows reduced brain FC as early as 24weeks, and the main effect of hypertension shows higher brain FC in SHRs. The novel discovery is that 1 brain FC network increased linearly with age in SHRs, in addition to the linearly decreasing FC. Hypertension and aging independently contribute to spatiotemporal alterations in brain function in SHRs following ongoing progression and compensation. This study provides new insight into the dynamic characteristics of brain function.

Aerobic Exercise Training Improves Renal Injury in Spontaneously Hypertensive Rats by Increasing Renalase Expression in Medulla.

We aimed to examine the effects of aerobic exercise training on renal function in spontaneously hypertensive rats (SHR) and elucidate their possible mechanisms. Adult male SHR and age-matched Wistar-Kyoto rats (WKY) were divided into four groups: WKY sedentary group, SHR sedentary group, low-intensity training group, and medium-intensity training group. Using molecular and biochemical approaches, we investigated the effects of 14-week training on renalase (RNLS) protein levels, renal function, and apoptosis and oxidative stress modulators in kidney tissues. In vitro, angiotensin II (Ang II)-induced human kidney proximal epithelial cells (HK-2) were treated with RNLS, and changes in apoptosis and oxidative stress levels were observed. Our results show that moderate training improved renal function decline in SHR. In addition, aerobic exercise therapy significantly increased levels of RNLS in the renal medulla of SHR. We observed in vitro that RNLS significantly inhibited the increase of Ang II-inducedapoptosis and oxidative stress levels in HK-2. In conclusion, aerobic exercise training effectively improved renal function in SHR by promoting RNLS expression in the renal medulla. These results explain the possible mechanism in which exercise improves renal injury in hypertensive patients and suggest RNLS as a novel therapy for kidney injury patients.

The Vasoactive Effect of Perivascular Adipose Tissue and Hydrogen Sulfide in Thoracic Aortas of Normotensive and Spontaneously Hypertensive Rats.

The objective of this study was to investigate the vasoregulatory role of perivascular adipose tissue (PVAT) and its mutual interaction with endogenous and exogenous H2S in the thoracic aorta (TA) of adult normotensive Wistar rats and spontaneously hypertensive rats (SHRs). In SHRs, hypertension was associated with cardiac hypertrophy and increased contractility. Regardless of the strain, PVAT revealed an anticontractile effect; however, PVAT worsened endothelial-dependent vasorelaxation. Since H2S produced by both the vascular wall and PVAT had a pro-contractile effect in SHRs, H2S decreased the sensitivity of adrenergic receptors to noradrenaline in Wistar rats. While H2S had no contribution to endothelium-dependent relaxation in Wistar rats, in SHRs, H2S produced by the vascular wall had a pro-relaxant effect. We observed a larger vasorelaxation induced by exogenous H2S donor in SHRs than in Wistar rats. Additionally, in the presence of PVAT, this effect was potentiated. We demonstrated that PVAT of the TA aggravated endothelial function in SHRs. However, H2S produced by the TA vascular wall had a pro-relaxation effect, and PVAT revealed anti-contractile activity mediated by the release of an unknown factor and potentiated the vasorelaxation induced by exogenous H2S. All these actions could represent a form of compensatory mechanism to balance impaired vascular tone regulation.

Icarrin prevents cardiomyocyte apoptosis in spontaneously hypertensive rats by inhibiting endoplasmic reticulum stress pathways.

This study aimed to explore whether icarrin (ICA) can protect cardiomyocytes from hypertension-induced damage by inhibiting endoplasmic reticulum stress (ERS). Spontaneously hypertensive rats (SHRs) were orally administered water or ICA at 10, 20 and 40 mg/kg once daily for 12 weeks, and Wistar-Kyoto (WKY) rats were used as control. Changes in the growth and blood pressure of rats were assessed. Cardiac function was determined by ultrasound and the left ventricle mass was calculated. Myocardial tissue structure was assessed by haematoxylin and eosin staining, cardiomyocyte apoptosis was observed by TUNEL staining and the expression of ERS-related proteins was determined by western blotting. In the SHR group, blood pressure was significantly high, left ventricular function decreased and left ventricular mass index increased. Additionally, left ventricular cardiomyocyte hypertrophy, disordered myofilament arrangement and increased cardiomyocyte apoptosis were observed by histological staining. ERS-induced proteins associated with apoptosis, including GRP78, PERK, ATF-6, ATF-4, CHOP, DR5, Caspase 12, c-JUN and ASK-1 were found to be highly expressed. ICA treatment reduced blood pressure and regulated the expression of proteins induced by ERS. Cardiomyocyte apoptosis decreased and left ventricular function improved. ICA can inhibit ERS-induced apoptosis of cardiomyocytes and protect ventricular function in SHR.

CIHH protects the heart against left ventricular remodelling and myocardial fibrosis by balancing the renin-angiotensin system in SHR

AimThe aim of our study was to clarify the cardioprotection of chronic intermittent hypobaric hypoxia (CIHH) and the underlying mechanism in spontaneously hypertensive rats (SHR). Main methodsAdult male rats were divided into normal blood pressure Wistar-Kyoto rats (WKY) control (WKY-CON), WKY rats with CIHH treatment (WKY-CIHH), SHR control (SHR-CON) and SHR with CIHH treatment (SHR-CIHH) groups. SHR-CIHH and WKY-CIHH rats were subjected to hypobaric hypoxia simulating 4000-m altitude for 35 days, 5 h per day. Arterial blood pressure and cardiac function parameters, including ejection fraction, fractional shortening and left ventricular (LV) wall thickness, were evaluated. Cardiac pathomorphology and myocardial fibrosis were determined. The expression of angiotensin-converting enzyme (ACE), ACE2, Ang II, Ang1-7, AT1 receptor, Mas receptor, IL-6, TNF-α，IL-10, SOD and MDA were assayed in myocardium. Key findingsCIHH significantly decreased arterial blood pressure, alleviated LV hypertrophy, and improved cardiovascular function in SHR (P < 0.05–0.01). Also, CIHH protected SHR heart against morphological changes and fibrosis. In addition, CIHH significantly down-regulated the ACE/Ang II/AT1 receptor axis and up-regulated the ACE2/Ang1–7/Mas axis of renin-angiotensin system (RAS) in SHR (P < 0.05–0.01). CIHH significantly reduced IL-6, TNF-α, and MDA levels, but increased IL-10 and SOD in SHR myocardium (P < 0.05–0.01). SignificanceThe CIHH treatment protected the heart of SHR against LV remodelling and myocardial fibrosis, which might be carried out through a balance in the ACE/Ang II/AT1 axis and the ACE2/Ang1–7/Mas axis of the RAS to reduce inflammation, and inhibit oxidative stress.

Sinapine Thiocyanate Ameliorates Vascular Endothelial Dysfunction in Hypertension by Inhibiting Activation of the NLRP3 Inflammasome.

The increase of blood pressure is accompanied by the changes in the morphology and function of vascular endothelial cells. Vascular endothelial injury and hypertension actually interact as both cause and effect. A large number of studies have proved that inflammation plays a significant role in the occurrence and development of hypertension, but the potential mechanism between inflammation and hypertensive endothelial injury is still ambiguous. The purpose of this study was to explore the association between the activation of NLRP3 inflammasome and hypertensive endothelial damage, and to demonstrate the protective effect of sinapine thiocyanate (ST) on endothelia in hypertension. The expression of NLRP3 gene was silenced by tail vein injection of adeno-associated virus (AAVs) in spontaneously hypertensive rats (SHRs), indicating that activation of NLRP3 inflammasome accelerated hypertensive endothelial injury. ST not only protected vascular endothelial function in SHRs by inhibiting the activation of NLRP3 inflammasome and the expression of related inflammatory mediators, but also improved AngII-induced huvec injury. In summary, our results show that alleviative NLRP3 inflammasome activation attenuates hypertensive endothelial damage and ST ameliorates vascular endothelial dysfunction in hypertension via inhibiting activation of the NLRP3 inflammasome.

Abstract 13013: Grk4-mediated Adiponectin Receptor-1 Phosphorylative Desensitization as a Novel Mechanism of Reduced Renal Sodium Excretion in Hypertension

Introduction: Hypertensive patients have impaired sodium excretion. However, the mechanisms are incompletely understood. There is interaction between kidney and adipose tissue. Whether and how adiponectin, one of adipokines, contributes to impaired sodium excretion in hypertension has not been previously investigated. Hypothesis: Adiponectin promotes natriuresis and diuresis and their impairment is involved in hypertension. Methods: We used Wistar-Kyoto (WKY) rats, spontaneously hypertensive rats (SHRs), GRK4g142A&gt;V transgenic mice to test the natriuresis-effect of adiponectin through intrarenal arterial infusion. Renal proximal tubule (RPT) cells, adiponectin knock out (Adipo-/-) mice, mutant plasmid were used. Results: We demonstrate that sodium excretion was reduced in Adipo-/- mice. The intrarenal arterial infusion of adiponectin induced natriuresis and diuresis in WKY rats, which was impaired in SHRs. Adiponectin inhibited Na+-K+-ATPase activity in RPT cells from WKY rats but not from SHRs. Increased adiponectin receptor phosphorylation and subsequent uncoupling from Gai, rather than altered adiponectin receptor expression, were responsible for the loss of adiponectin-mediated inhibition of RPT Na+-K+-ATPase activity, impaired natriuresis and diuresis in SHRs. Mutation of the AdipoR1 phosphorylation site restored its linkage to Gai and the adiponectin-mediated inhibition of Na+-K+-ATPase activity in RPT cells from SHRs. Finally, we identified G protein-coupled receptor kinase 4 (GRK4) as the cause of adiponectin receptor hyper-phosphorylation. GRK4g142A&gt;V transgenic mice replicated the abnormal adiponectin function in SHRs, whereas down-regulation of GRK4 by renal-ultrasound directed siRNA restored the adiponectin-mediated sodium excretion and reduced the blood pressure in SHRs. Conclusions: The stimulatory effect of adiponectin on sodium excretion is impaired in hypertension, which is attributable to increased renal GRK4 expression and subsequent adiponectin receptor hyper-phosphorylation. Targeting GRK4/adiponectin receptor/Gai may restore the impaired adiponectin-mediated sodium excretion in hypertension, thus representing a novel strategy against hypertension.

PDE5 inhibition improves cardiac morphology and function in SHR by reducing NHE1 activity: Repurposing Sildenafil for the treatment of hypertensive cardiac hypertrophy

Previously, we have shown that an increased cGMP-activated protein Kinase (PKG) activity after phosphodiesterase 5 (PDE5) inhibition by Sildenafil (SIL), leads to myocardial Na+/H+ exchanger (NHE1) inhibition preserving its basal homeostatic function. Since NHE1 is hyperactive in the hypertrophied myocardium of spontaneous hypertensive rats (SHR), while its inhibition was shown to prevent and revert this pathology, the current study was aimed to evaluate the potential antihypertrophic effect of SIL on adult SHR myocardium. We initially tested the inhibitory capability of SIL on NHE1 in isolated cardiomyocytes of SHR by comparing H+ efflux during the recovery from an acid load. After confirmed that effect, eight-month-old SHR were chronically treated for one month with SIL through drinking water. Compared to their littermate controls, SIL-treated rats presented a decreased NHE1 activity, which correlated with a reduction in its phosphorylation level assigned to activation of a PKG-p38 MAP kinase-PP2A signaling pathway. Moreover, treated animals showed a decreased oxidative stress that appears to be a consequence of a decreased mitochondrial NHE1 phosphorylation. Treated SHR showed a significant reduction in the pro-hypertrophic phosphatase calcineurin, despite slight tendency to decrease hypertrophy was detected. When SIL treatment was prolonged to three months, a significant decrease in myocardial hypertrophy and interstitial fibrosis that correlated with a lower myocardial stiffness was observed. In conclusion, the current study provides evidence concerning the ability of SIL to revert established cardiac hypertrophy in SHR, a clinically relevant animal model that resembles human essential hypertension.

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.

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. 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 (eNOS) and Ang (1-7) levels, as well as ACE2, Mas receptor and neuronal nitric oxide synthase (nNOS) protein expression. 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), eNOS and NO. Moreover, HEBSP significantly elevated the expression levels of ACE2, Mas receptor and nNOS. These beneficial effects were elevated in the high-dose HEBSP group. HEBSP improved erectile function in SHRs by upregulating the ACE2/Ang (1-7)/Mas receptor axis, eNOS and nNOS pathways.

Calcitriol ameliorated autonomic dysfunction and hypertension by down-regulating inflammation and oxidative stress in the paraventricular nucleus of SHR

The hypothalamic paraventricular nucleus (PVN) plays crucial roles in central cardiovascular regulation. Increasing evidence in humans and rodents shows that vitamin D intake is important for achieving optimal cardiovascular function. The purpose of this study was to investigate whether calcitriol, an active form of vitamin D, improves autonomic and cardiovascular function in hypertensive rats and whether PVN oxidative stress and inflammation are involved in these beneficial effects. Male spontaneously hypertensive rats (SHR) and normotensive control Wistar Kyoto (WKY) rats were treated with either calcitriol (40 ng/day) or vehicle (0.11 μL/h) through chronic PVN infusion for 4 weeks. Blood pressure and heart rate were recorded continuously by radiotelemetry. PVN tissue, heart and plasma were collected for molecular and histological analysis. Compared to WKY rats, SHR exhibited increased systolic blood pressure, sympathetic drive, and cardiac hypertrophy and remodeling. These were associated with higher mRNA and protein expression levels of high mobility box 1 (HMGB1), receptor for advanced glycation end products (RAGE), toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), proinflammatory cytokines, NADPH oxidase subunit in the PVN. In addition, increased norepinephrine in plasma, elevated reactive oxygen species levels and activation of microglia in the PVN were also observed in SHR. Chronic calcitriol treatment ameliorated these changes but not in WKY rats. Our results demonstrate that chronic infusion of calcitriol in the PVN ameliorates hypertensive responses, sympathoexcitation and retains cardiovascular function in SHR. Reduced inflammation and oxidative stress within the PVN are involved in these calcitriol-induced effects.

Role of Granulocyte-colony Stimulating Factor in the Protection of Cerebral Vascular Endothelium, White Matter, and Cognition.

Granulocyte-colony stimulating factor (G-CSF) has protective effects on many neurological diseases. The effects of G-CSF on vascular endothelium and White Matter (WM) injury in Cerebral Small Vessel Disease (CSVD) were explored in this study via a model of spontaneously hypertensive rat (SHR) in order to elucidate the mechanism of G-CSF in Vascular Cognitive Impairment (VCI). 24-week-old male SHRs were randomly divided into the treatment group and model group, with the same age Wistar rats as the control group. The novel object recognition test (NORT) and Morris water maze were conducted after 7 days of G-CSF(50ug/kg) or normal saline treatment to examine their non-spatial and spatial cognitive functions. After that, a transmission electron microscope (TEM) and FLB staining were used to observe the vascular endothelial cell and WM damage. Furthermore, the expression of VEGF, MMP-9, Caspase-3, TUNEL and BrdULaminin in the cortical area was detected by immunostaining methods. Our results showed that G-CSF promoted the expression of VEGF and BrdU+-Laminin+ endothelial cells, but down-regulated the level of MMP-9, thus significantly repaired the cerebral vascular endothelial cells and perivascular structure in SHR. The WM damage, the expression of caspase-3 and the apoptosis rate decreased after G-CSF treatment. Ultimately, G-CSF improved the non-spatial cognitive function in SHR rather than the spatial cognitive function. Therefore, our findings indicated that G-CSF might facilitate the improvement of non-spatial cognitive function in CSVD by repairing endothelial cells and alleviating WM damage.

Tianma Gouteng Decoction Exerts Cardiovascular Protection by Upregulating OPG and TRAIL in Spontaneously Hypertensive Rats.

Tianma Gouteng Decoction (TGD) is widely used in traditional Chinese medicine for the treatment of hypertension and its related complications, but its mechanisms remain incompletely defined. We now aim to assess the protective effect of TGD against cardiovascular damage and to investigate its characteristics and underlying mechanisms. Blood pressure was determined in TGD-treated spontaneously hypertensive rats (SHR) by noninvasive measurements. Echocardiography was performed to assess cardiac function and structure and sirius red staining to evaluate cardiac fibrosis, and the degree of vascular remodeling was evaluated. Additionally, vasoconstriction and relaxation factor expression changes were examined by means of ELISA. Protein expression changes were verified by western blot. Compared with untreated SHR, TGD-treated SHR exhibited cardiovascular traits more akin to those of the normotensive Wistar Kyoto (WKY) rats. That is, they had lower diastolic blood pressure, systolic blood pressure and mean BP, and increased expression of vasodilation factor. We also found that TGD reduces ventricular and vascular remodeling and improves cardiac function in SHR. Finally, we tested the antiapoptosis effect TGD exerts in SHR, ostensibly by upregulating the expression of OPG, TRAIL, and death receptor 5 (DR5) and downregulating caspases 8, 7, and 3. TRAIL may also exert antiapoptotic and prosurvival effects by upregulating AKT expression. Therefore, TGD may reverse cardiovascular remodeling in SHR by upregulating the expression of OPG and TRAIL, upregulating AKT, and inhibiting apoptosis, at least in part. For the first time, we have shown that OPG and TRAIL play complimentary cardioprotective roles in SHR.

Qingxuan Jiangya Decoction () Prevents Blood Pressure Elevation and Ameliorates Vascular Structural Remodeling via Modulating TGF-β 1/Smad Pathway in Spontaneously Hypertensive Rats.

To elevate the effects of Qingxuan Jiangya Decoction (, QXJYD) on hypertension and vascular structural remodeling (VSR) in spontaneously hypertensive rats (SHRs), and investigate the underlying mechanisms. SHRs (n=8) were given intra-gastric administration with 60 mg/kg of QXJYD or saline, daily for 8 weeks, while rats in SHR-control (n=8) and WKY (n=8) groups were received equal volumes of saline solution. Systolic blood pressures (SBP), diastolic blood pressures (DBP) and mean blood pressures (MBP) were measured once a week. The levels of angiotensin II (Ang II), endothelin 1 (ET-1) and plasma renin activity (PRA) were tested by enzyme-linked immunosorbent assay (ELISA) and radioimmunoassay, respectively. The effect of QXJYD on VSR was determined by examining the media thickness and the ex vivo contractility of thoracic aortic. The proliferation and fibrosis of vascular smooth muscle cells (VSMCs) were examined via immunohistochemical (IHC) staining for proliferating cell nuclear antigen (PCNA), collagen I and collagen III, respectively. The mRNA and protein expressions of transforming growth factor β 1 (TGF-β 1), Smad3 and phosphorylation of Smad3 in thoracic aorta tissues were determined by real-time polymerase chain reaction (PCR) and Western blot assay, respectively. QXJYD treatment led to a significant decrease of the elevation of blood pressure in SHRs and reduced the levels of Ang II, ET-1 and PRA in the serum (P<0.05). In addition, QXJYD treatment remarkably ameliorated VSR and vascular function in SHRs. Moreover, QXJYD inhibited VSMC proliferation and fibrosis by suppressing the expression of PCNA, collagen I and collagen III in thoracic aortic. Furthermore, QXJYD inhibited the expression of TGF-β 1, Smad3 and the phosphorylation of Smad3, respectively (P<0.05). QXJYD reversed VSR by inhibiting VSMC proliferation and collagen deposition via regulation of TGF-β 1/Smad signaling pathway, which may, in part, illuminate its anti-hypertensive activities.

Effects of Tetrahydrobiopterin Combined with Nebivolol on Cardiac Diastolic Function in SHRs.

This study aimed to evaluate the effects of combined use of tetrahydrobiopterin (BH4) and nebivolol on cardiac diastolic dysfunction in spontaneously hypertensive rats (SHRs). Twelve-week-old male SHRs were treated with BH4, nebivolol, or a combination of both. Left ventricle function was evaluated, and reactive oxygen species (ROS) production (including dihydroethidium (DHE) and 3-nitrotyrosine (3-NT)), nitric oxide synthase (NOS) activity and the level of NO in myocardial tissue were determined. The expression levels of endothelial NOS (eNOS), phospholamban (PLN), sarcoplasmic reticulum Ca2+ ATPase (SERCA2a), β3-adrenoceptor, cyclic guanosine monophosphate (cGMP), and protein kinase G (PKG) were assayed. Treatment with BH4, nebivolol, or both reversed the noninvasive indexes of diastolic function, including E/E' and E'/A', and the invasive indexes, including time constant of isovolumic left ventricle (LV) relaxation (tau), -dP/dtmin, -dP/dtmin/LV systolic pressure (LVSP), and LV end-diastolic pressure (LVEDP) in SHRs. mRNA and protein expression levels of eNOS dimer, phosphorylated PLN, SERCA2a, cGMP, and PKG in the myocardium of treated SHRs were significantly up-regulated compared with those in control rats (p < 0.05 or p < 0.01). The expression levels of 3-NT and DHE were reduced in all treated groups (p < 0.05 or p < 0.01). Notably, combined use of BH4 and nebivolol had better cardioprotective effects than monotherapies. BH4 or nebivolol has a protective effect on diastolic dysfunction in SHRs, and BH4 combined with nebivolol may exert a synergistically cardioprotective effect through activation of β3-adrenoceptor and the NO/cGMP/PKG signaling pathway.

Regulation of DNA methylation and 2-OG/TET signaling by choline alleviated cardiac hypertrophy in spontaneously hypertensive rats

DNA methylation is a well-defined epigenetic modification that regulates gene transcription. However, the role of DNA methylation in the cardiac hypertrophy seen in hypertension is unclear. This study was performed to investigate genome-wide DNA methylation profiles in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats (WKY), and the cardioprotective effect of choline. Eight-week-old male SHRs received intraperitoneal injections of choline (8 mg/kg/day) for 8 weeks. SHRs showed aberrant methylation distribution on chromosomes and genome regions, with decreased methylation levels at CHG and CHH sites. A total of 91,559 differentially methylated regions (DMRs) were detected between SHRs and WKY rats, of which 28,197 were demethylated and 63,362 were methylated. Choline treatment partly restored the DMRs in SHRs, which were related to 131 genes. Gene ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis of DMRs suggested that choline partly reversed the dysfunctions of biological processes, cellular components and molecular functions in SHRs. Moreover, the inhibition of 2-oxoglutarate accumulation by choline, thereby inhibiting excessive activation of ten-eleven translocation methylcytosine dioxygenase enzymes, may correlate with the beneficial effects of choline on methylation levels, cardiac hypertrophy and cardiac function of SHRs, as indicated by decreased heart rate and blood pressure, and increased ejection fraction and fractional shortening. This study provides the first genome-wide DNA methylation profile of the hypertrophic myocardium of SHRs and suggests a novel role for this epigenetic modification in hypertension. Choline treatment may represent a promising approach for modification of DNA methylation and optimization of the epigenetic profile for antihypertensive therapy.

CARDIOPROTECTIVE EFFECT OF THE RED PALM OIL SUPPLEMENTATION ON THE CARDIAC OXIDATIVE STRESS, NITRIC OXIDE SYNTHASE AND HEART FUNCTION IN THE RATS SUFFERING FROM HYPERTENSION

Objective: We know from our previous study that myocardial protein connexin 43 (Cx43), responsible for intercellular communication, and protein kinase C epsilon which directly phosphorylates Cx43 on the serine 368, were significantly decreased in spontaneously hypertensive rats (SHR) what was also associated with increased incidence to malignant arrhythmias. Antioxidant rich red palm oil (RPO) significantly normalized all of these parameters. Therefore, we further aimed to investigate whether intake of RPO may affect endothelial dysfunction, antioxidant enzymes and heart function in SHR. Design and method: In accordance with the rules issued by the State Veterinary Administration of the Slovak Republic and European Union Council Directive 86/609/EEC we used in our experiment 3-months-old, male SHR and normotensive Wistar-Kyoto control rats fed standard rat chow without or with RPO (0.2 ml/day/5 weeks). Left ventricular tissue was used to examine expression of antioxidant enzymes such as superoxide dismutases (SOD1, SOD2) and glutathione peroxidases (GPx) as well as activity of nitric oxide synthase (NOS). Functional parameters of the heart were measured during basal conditions and at the early-phase of post-ischemic reperfusion by Langendorff-perfused system. Results: RPO supplementation significantly normalized higher blood pressure and total NOS activity as well as increased lowered expression of mitochondrial SOD2 in SHR hearts during basal condition. RPO intake resulted in the suppression of elevated heart rate, increase of reduced coronary flow and enhancement of systolic and diastolic heart function at the early-phase of post-ischemic reperfusion. Conclusions: We can conclude that SHR benefit from RPO intake due to its apparent anti-arrhythmic effects by Cx43 modulation, reduction of blood pressure, enhancement of oxidative stress and protection of heart function that was deteriorated by post-ischemic reperfusion.