Kaempferol protects against cardiovascular abnormalities induced by nitric oxide deficiency in rats by suppressing the TNF-α pathway

Kaempferol is a natural flavonoid compound that exhibits various pharmacological actions. However, there are few reports regarding the role of kaempferol in cardiovascular abnormalities. This study aimed to assess whether kaempferol could prevent cardiovascular malfunction and hypertrophy provoked by chronic inhibition of nitric oxide (NO) formation in rats. Rats (180-200 g) were treated daily with Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) (40 mg/kg, in drinking water) for five weeks concomitant with kaempferol (oral administration) at a dose of 20 mg/kg or 40 mg/kg or lisinopril (5 mg/kg). Kaempferol partially prevented the progression of hypertension provoked by NO inhibition (p < 0.05). Left ventricular malfunction and hypertrophy present in hypertensive rats were alleviated by concurrent administration of kaempferol (p < 0.05). Furthermore, L-NAME rats had increased sympathetic nerve-mediated vasoconstriction and decreased acetylcholine-induced vasorelaxation and aortic wall thickening, which were resolved by kaempferol treatment (p < 0.05). Kaempferol restored tissue superoxide formation, malondialdehyde, catalase activity, plasma nitric oxide metabolites, tumor necrosis factor-alpha (TNF-α) and interleukin-6 in L-NAME rats (p < 0.05). Overexpression of tumor necrosis factor receptor 2 (TNFR2), phosphatidylinositol 3-kinases (PI3K), AKT serine/threonine kinase 1 (Akt1) and smad2/3 in heart tissue and upregulation of tumor necrosis factor receptor 1 (TNFR1), phosphorylated nuclear factor-kappaB (p-NF-κB) and transforming growth factor beta 1 (TGF-β1) in vascular tissue were suppressed by kaempferol (p < 0.05). In conclusion, kaempferol exerts antihypertensive, cardioprotective, antioxidant, and anti-inflammatory effects in NO-dependent hypertensive rats. The underlying mechanisms of kaempferol in preventing cardiovascular changes induced by L-NAME were due to the suppression of the TNF-α pathway.

Cardiovascular complications are resolved by tuna protein hydrolysate supplementation in rats fed with a high-fat diet

This study is aimed to investigate whether tuna protein hydrolysate (TPH) supplementation could alleviate cardiovascular complications induced by a high-fat diet (HFD) in rats. Rats were fed a HFD for 16 weeks and given TPH (100 mg/kg, 300 mg/kg, or 500 mg/kg) or metformin (100 mg/kg) (n = 8) for the last four weeks. TPH had the following effects: resolved their impaired glucose tolerance, hyperglycemia, dyslipidemia, obesity, and hypertension (p < 0.05); alleviated left ventricular dysfunction and hypertrophy (p < 0.05), and vascular dysfunction and hypertrophy (p < 0.05); adipocyte hypertrophy; increases in circulating leptin and tumor necrosis factor (TNF-α) were mitigated (p < 0.05); increased renin-angiotensin system (RAS), oxidative stress, and decreased nitric oxide metabolites were modulated (p < 0.05). TPH restored the expression of angiotensin II receptor type 1 (AT1R)/NADPH oxidase 2 (NOX2), endothelial nitric oxide synthase (eNOS), nuclear factor erythroid 2-related factor (Nrf2)/heme oxygenase-1 (HO-1), and peroxisome proliferator-activated receptor γ (PPARγ)/the nuclear factor kappa B (NF-κB) protein in cardiovascular tissue (p < 0.05). In metabolic syndrome (MS) rats, metformin and TPH had comparable effects. In conclusion, TPH alleviated cardiovascular complications related to MS. It suppressed RAS, oxidative stress, and inflammation that were associated with modulation of AT1R/NOX2, eNOS, Nrf2/HO-1, and PPARγ/NF-κB expression.

Limonin ameliorates cardiovascular dysfunction and remodeling in hypertensive rats

AIMS

Limonin is a tetracyclic triterpenoid isolated from citrus fruits. Here, the effects of limonin on cardiovascular abnormalities in nitric oxide-deficient rats induced by N^ω-Nitrol-arginine methyl ester (L-NAME) were explored.

MAIN METHODS

Male Sprague Dawley rats were given L-NAME (40 mg/kg, drinking water) for 3 weeks and then treated daily with polyethylene glycol (vehicle), limonin (50 or 100 mg/kg) or telmisartan (10 mg/kg) for two weeks.

KEY FINDINGS

Limonin (100 mg/kg) markedly reduced L-NAME-induced hypertension, cardiovascular dysfunction and remodeling in rats (P < 0.05). Increases in systemic angiotensin-converting enzyme (ACE) activity and angiotensin II (Ang II) and a reduction in circulating ACE2 were restored in hypertensive rats treated with limonin (P < 0.05). Reductions in antioxidant enzymes and nitric oxide metabolites (NOx) and increases in oxidative stress components induced by L-NAME were relieved by limonin treatment (P < 0.05). Limonin suppressed the increased expression of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in cardiac tissue and circulating TNF-α in rats that received L-NAME (P < 0.05). Changes in Ang II receptor type I (AT1R), Mas receptor (MasR), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB) and NADPH oxidase subunit 2 (gp91^phox) protein expression in cardiac and aortic tissue were normalized by limonin (P < 0.05).

SIGNIFICANCE

In conclusion, limonin ameliorated L-NAME-induced hypertension, cardiovascular dysfunction and remodeling in rats. These effects were relevant to restorations of the renin-angiotensin system, oxidative stress and inflammation in NO-deficient rats. The molecular mechanisms are associated with the modulation of AT1R, MasR, NF-ĸB and gp91^phox protein expression in cardiac and aortic tissue.

Mitigation effect of galangin against aortic dysfunction and hypertrophy in rats with metabolic syndrome

Vascular alterations induced by a high-fat diet (HFD) are involved in the development of hypertension. Galangin, a flavonoid, is the major active compound isolated from galangal and propolis. The objective of this study was to investigate the effect of galangin on aortic endothelial dysfunction and hypertrophy, and the mechanisms involved in HFD-induced metabolic syndrome (MS) in rats. Male Sprague-Dawley rats (220-240 g) were separated into three groups: control + vehicle, MS + vehicle, and MS + galangin (50 mg/kg). Rats with MS received HFD plus 15% fructose solution for 16 weeks. Galangin or vehicle was orally administered daily for the final four weeks. Galangin reduced body weight and mean arterial pressure in HFD rats (p < 0.05). It also reduced circulating fasting blood glucose, insulin, and total cholesterol levels (p < 0.05). Impaired vascular responses to the exogenous acetylcholine observed in the aortic ring of HFD rats were restored by galangin (p < 0.05). However, the response to sodium nitroprusside did not differ between the groups. Galangin enhanced the expression of the aortic endothelial nitric oxide synthase (eNOS) protein and increased circulating nitric oxide (NO) levels in the MS group (p < 0.05). Aortic hypertrophy in HFD rats was alleviated by galangin (p < 0.05). Increases in tumour necrosis factor-alpha (TNF-α), interleukin (IL)-6 levels, angiotensin-converting enzyme activity and angiotensin II (Ang II) concentrations in rats with MS were suppressed in galangin treated group (p < 0.05). Furthermore, galangin reduced the upregulation of angiotensin II type I receptor (AT1R) and transforming growth factor-beta (TGF-β) expression in rats with MS (p < 0.05). In conclusion, galangin alleviates metabolic disorders and improves aortic endothelial dysfunction and hypertrophy in the MS group. These effects were consistent with increased NO availability, reduced inflammation, and suppressing Ang II/AT1R/TGF-β signalling pathway.

Effects of Thai native chicken breast meat consumption on serum uric acid level, biochemical parameters, and antioxidant activities in rats

This study aimed to evaluate the effect of a high protein diet comprising breast meat from commercial broiler (BR), Thai native (PD), and commercial broiler × Thai native crossbred (KKU-ONE) chicken on serum uric acid, biochemical parameters, and antioxidant activities in rats. Male Sprague–Dawley rats were divided into four groups. The control group received a standard chow diet, and the other three groups were fed a high protein diet (70% standard diet + 30% BR, PD, or KKU-ONE chicken breast) for five weeks. The PD- and KKU-ONE-fed rats had lower plasma total cholesterol and triglyceride levels than the control rats. A decrease in HDL-c was also observed in rats fed a diet containing BR. Liver weight, liver enzyme, plasma ALP, xanthine oxidase activity, serum uric acid, creatinine, superoxide production, and plasma malondialdehyde levels increased in BR-fed rats. The findings of this study might provide evidence to support the use of Thai native and Thai native crossbred chicken breast meat as functional foods.

Cardiorenal dysfunction and hypertrophy induced by renal artery occlusion are normalized by galangin treatment in rats

Galangin is a polyphenolic compound found in Alpinia officinarum and propolis. This study investigated the effect of galangin on blood pressure, the renin angiotensin system (RAS), cardiac and kidney alterations and oxidative stress in two-kidney one-clipped (2K-1C) hypertensive rats. Hypertension was induced in male Sprague Dawley rats (180-220 g), and the rats were given galangin (30 and 60 mg/kg) and losartan (10 mg/kg) for 4 weeks (n = 8/group). Galangin decreased hypertension and cardiac dysfunction and hypertrophy, which was related to the reducing circulation angiotensin converting enzyme (ACE) activity and angiotensin II concentration (p < 0.05). These effects were consistent with the reduced overexpression of angiotensin II receptor type 1 (AT₁R), transforming growth factor beta 1 (TGF-β1) and collagen type I (Col I) protein in cardiac tissue (p < 0.05). Additionally, renal artery occlusion, procedure-induced kidney dysfunction and fibrosis were attenuated in the galangin-treated group. Galangin treatment normalized the overexpression of AT₁R and NADPH oxidase 4 (Nox-4) protein and normalized the downregulation of nuclear factor-erythroid Factor 2-related Factor 2 (Nrf-2) and haem oxygenase 1 (HO-1) in 2K-1C rats (p < 0.05). Galangin exhibited antioxidative effects, as it reduced systemic and tissue oxidative stress markers and increased catalase activity in 2K-1C rats (p < 0.05). In conclusion, galangin attenuated hypertension, renin-angiotensin system activation, cardiorenal damage and oxidative stress induced by renal artery stenosis in rats. These effects might be associated with modulation of the expression of AT₁R, TGF-β1 and Col I protein in the heart as well as AT₁R/Nox-4 and Nrf-2/HO-1 protein in renal tissue in hypertensive rats.

Nobiletin resolves left ventricular and renal changes in 2K-1C hypertensive rats

This study investigated the effects of nobiletin on cardiorenal changes and the underlying mechanisms involved in two-kidney, one-clip (2K-1C) hypertension. 2K-1C rats were treated with nobiletin (15 or 30 mg/kg/day) or losartan (10 mg/kg/day) for 4 weeks (n = 8/group). Nobiletin (30 mg/kg) reduced high levels of blood pressure and circulating angiotensin II and angiotensin-converting enzyme activity in 2K-1C rats. Left ventricular (LV) dysfunction and remodelling in 2K-1C rats were alleviated in the nobiletin-treated group (P < 0.05). Nobiletin reduced the upregulation of Ang II type I receptor (AT₁R)/JAK (Janus kinase)/STAT (signal transducer and activator of transcription) protein expression in cardiac tissue of 2K-1C rats (P < 0.05). The reduction in kidney function, and accumulation of renal fibrosis in 2K-1C rats were alleviated by nobiletin (P < 0.05). Overexpression of AT₁R and NADPH oxidase 4 (Nox4) protein in nonclipped kidney tissue was suppressed in the nobiletin-treated group (P < 0.05). The elevations in oxidative stress parameters and the reductions in antioxidant enzymes were attenuated in 2K-1C rats treated with nobiletin (P < 0.05). In summary, nobiletin had renin-angiotensin system inhibitory and antioxidant effects and attenuated LV dysfunction and remodelling via restoration of the AT₁R/JAK/STAT pathway. Nobiletin also resolved renal damage that was related to modulation of the AT₁R/Nox4 cascade in 2K-1C hypertension.

Clitoria ternatea (Linn.) flower extract attenuates vascular dysfunction and cardiac hypertrophy via modulation of Ang II/AT1 R/TGF-β1 cascade in hypertensive rats

BACKGROUND

Clitoria ternatea (CT) (the Fabaceae family) has been reported to elicit several biological responses, such as anti-inflammation and anti-depression effects. This study evaluated the effect of CT flower extract on blood pressure, vascular function, and left ventricular hypertrophy in a two-kidney, one-clip (2K-1C) rat model. Hypertensive rats were treated with CT extract at various doses (100, 300, or 500 mg kg^-1  day^-1 ) or losartan (10 mg kg^-1  day^-1 ) for 4 weeks (n = 8/group).

RESULTS

CT extract reduced blood pressure in a dose-dependent manner, and CT extract at a dose of 300 mg kg^-1 was an effective concentration (P < 0.05). Augmentation of contractile responses to electrical field stimulation and impairment of vascular responses to acetylcholine in mesenteric vascular beds and aortic rings of 2K-1C rats were suppressed by treatment with CT extract or losartan (P < 0.05). Serum angiotensin-converting enzyme activity and plasma angiotensin II concentration were high in 2K-1C rats but alleviated by CT extract or losartan treatment (P < 0.05). Increases in superoxide production and lipid peroxidation were attenuated in 2K-1C rats treated with CT extract or losartan compared with the untreated group (P < 0.05). Increased plasma concentration of nitric oxide metabolites was found in hypertensive rats that received CT extract or losartan. CT extract or losartan suppressed the overexpression of Ang II receptor subtype I (AT₁ -R) and transforming growth factor-β1 (TGF-β1) in 2K-1C rats.

CONCLUSION

CT extract had antihypertensive effects that were associated with improving vascular function and cardiac hypertrophy in 2K-1C rats. The mechanisms involved suppression of the renin-angiotensin system, of oxidative stress, and of the AT₁ R/TGF-β1 cascade. © 2021 Society of Chemical Industry.

Galangin alleviates vascular dysfunction and remodelling through modulation of the TNF-R1, p-NF-κB and VCAM-1 pathways in hypertensive rats

Galangin is a natural flavonoid isolated from ginger, honey and propolis.

AIMS

To investigate the effect of galangin on blood pressure, vascular changes, sympathoexcitation, oxidative stress and inflammation in rats treated with N^G-nitro-l-arginine methyl ester (l-NAME).

MATERIALS AND METHODS

Male Wistar rats (220-250 g) were given l-NAME (0.5 mg/mL in drinking water) to induce hypertension for 5 weeks. They were treated with vehicle, galangin (30 or 60 mg/kg), or amlodipine (10 mg/kg) for the final two weeks (n = 6/group).

KEY FINDINGS

Galangin significantly reduced blood pressure and improved the impairment of endothelium-dependent vasodilation in hypertensive rats. Sympathoexcitation, including enhancement of contractile responses to electrical field stimulation, increases in intensity of tyrosine hydroxylase and plasma norepinephrine concentration in hypertensive rats, was attenuated by galangin treatment. Galangin also reduced systemic and vascular oxidative damage and increased plasma nitric oxide levels in the hypertensive groups. Aortic remodelling accompanied by aortic wall hypertrophy and fibrosis observed in hypertensive rats were alleviated by galangin treatment. Furthermore, galangin exhibited an anti-inflammatory effect by suppressing the upregulation of tumour necrosis factor receptor 1 (TNF-R1), phospho-nuclear factor kappa B (p-NF-κB) and vascular cell adhesion protein 1 (VCAM-1) in aortic tissue and reducing plasma tumour necrosis factor alpha (TNF-α) in l-NAME rats. In conclusion, galangin had antihypertensive effects that were relevant to attenuating endothelial dysfunction, sympathoexcitation and vascular remodelling. These effects might be contributed by antioxidant and anti-inflammatory capacities and modulation of the TNF-R1, p-NF-κB and VCAM-1 pathways in hypertensive rats.

Diosmetin Ameliorates Vascular Dysfunction and Remodeling by Modulation of Nrf2/HO-1 and p-JNK/p-NF-κB Expression in Hypertensive Rats

Diosmetin is a citrus flavonoid that has antioxidant and anti-inflammatory effects. This study examined the effect of diosmetin on blood pressure and vascular alterations and its underlying mechanisms in experimentally hypertensive rats. Male Sprague rats were administered Nω-nitro-l-arginine methyl ester L-NAME for five weeks and were given diosmetin at doses of 20 or 40 mg/kg or captopril (5 mg/kg) for two weeks. Diosmetin alleviated hypertension, improved endothelial dysfunction, and suppressed the overactivity of sympathetic nerve-mediated vasoconstriction in aorta and mesentery hypertensive rats (p < 0.05). Increases in plasma and aortic tissue malondialdehyde (MDA) and carotid superoxide generations and reductions of plasma superoxide dismutase, catalase, and nitric oxide in hypertensive rats were ameliorated by diosmetin (p < 0.05). Diosmetin increased the protein expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in hypertensive rats. Furthermore, diosmetin mitigated hypertrophy and collagen accumulation of the aortic wall in L-NAME rats. It exhibited an anti-inflammatory effect by reducing interleukin-6 (IL-6) accumulation and by overexpressing the phospho-c-Jun N-terminal kinases (p-JNK) and the phospho-nuclear factor-kappaB (p-NF-κB) proteins in the aorta (p < 0.05). Captopril was a positive control substance and had similar effects to diosmetin. In summary, diosmetin reduced blood pressure and alleviated vascular abnormalities in L-NAME-treated rats. These effects might be related to antioxidant and anti-inflammatory effects as well as to the modulation of the expression of the Nrf2/HO1 and p-JNK/NF-κB proteins.

Diosmetin attenuates metabolic syndrome and left ventricular alterations via the suppression of angiotensin II/AT receptor/gp91phox/p-NF-κB protein expression in high-fat diet fed rats

Diosmetin, a monomethoxyflavone, is isolated from citrus fruits. The objective of this research was to test the biological role of diosmetin on parameters of metabolic syndrome (MS) and left ventricular (LV) alterations in rats fed with a high-fat (HF) diet. MS was induced by feeding male Sprague-Dawley rats with a HF diet plus 15% fructose in drinking water for 16 weeks. MS rats were given diosmetin (20 or 40 mg per kg per day) or metformin (100 mg per kg per day) for the final four weeks. Diosmetin attenuated signs of MS including, hypertension, hyperglycemia, insulin resistance, and dyslipidemia in rats that received the HF diet (p < 0.05). A decreased stroke volume, ejection fraction, fractional shortening, LV hypertrophy and fibrosis present in the MS group were alleviated by diosmetin treatment (p < 0.05). Diosmetin also suppressed angiotensin-converting enzyme activity, plasma angiotensin II (Ang II) levels and angiotensin II type 1 (AT1) receptor protein expression in MS rats. Increases in superoxide (O2˙-) formation, plasma malondialdehyde, plasma nitrate and nitrite and gp91phox expression induced by a HF diet were ameliorated in the diosmetin treated group. Inflammation indicated by an increased phospho nuclear factor kappa B (p-NF-κB) protein expression and cardiac TNF-α concentration was reduced in MS rats receiving diosmetin (p < 0.05). Metformin also attenuated MS, cardiac abnormalities relevant to decreasing the renin-angiotensin system stimulation, reactive oxygen species and inflammation in MS rats (p < 0.05). Diosmetin alleviated MS and LV dysfunction and remodeling in HF diet-induced MS rats. These results could be associated with the suppression of the Ang II/AT1 receptor/gp91phox/p-NF-κB protein pathway.

Imperatorin alleviates metabolic and vascular alterations in high-fat/high-fructose diet-fed rats by modulating adiponectin receptor 1, eNOS, and p47phox expression

In the present study, the therapeutic effects of imperatorin on metabolic and vascular alterations and possible underlying mechanisms were investigated in high-fat/high-fructose diet (HFFD)-fed rats. Male Sprague-Dawley rats were fed a high-fat diet plus 15% fructose in drinking water for 16 weeks. HFFD-fed rats were treated with imperatorin (15 or 30 mg/kg/day) for the last 4 weeks. In HFFD-fed rats, imperatorin significantly reduced obesity, hypertension, dyslipidemia, and insulin resistance. Imperatorin markedly improved vascular endothelial function and alleviated changes in vascular morphology. Furthermore, imperatorin treatment significantly increased the plasma levels of the nitric oxide metabolite and adiponectin, and upregulated adiponectin receptor 1 and endothelial nitric oxide synthase (eNOS) protein expression in the thoracic aorta. Imperatorin treatment decreased vascular superoxide anion production and downregulated aortic NADPH oxidase subunit p47phox protein expression. These findings indicated that imperatorin alleviates HFFD-induced metabolic and vascular alterations in rats. The possible underlying mechanism may involve the restoration of adiponectin receptor 1 and eNOS expression and suppression of p47phox expression.

Butterfly Pea Flower (Clitoria ternatea Linn.) Extract Ameliorates Cardiovascular Dysfunction and Oxidative Stress in Nitric Oxide-Deficient Hypertensive Rats

In this study, we examine whether Clitoria ternatea Linn. (CT) can prevent Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced cardiac and vascular dysfunction in rats. Male Sprague Dawley rats were given L-NAME (40 mg/kg, drinking water) and orally administered with CT extract (300 mg/kg/day) or lisinopril (2.5 mg/kg/day) for 5 weeks. The main phytochemical components of the CT extract were found to be flavonoids. The CT extract alleviated the high blood pressure in rats receiving L-NAME. Decreased vasorelaxation responses to acetylcholine and enhanced contractile responses to sympathetic nerve stimulation in aortic rings and mesenteric vascular beds of L-NAME treated rats were ameliorated by CT extract supplementation. Left ventricular hypertrophy and dysfunction were developed in L-NAME rats, which were partially prevented by CT extract treatment. The CT extract alleviated upregulated endothelial nitric oxide synthase expression, decreased plasma nitrate/nitrite levels, and increased oxidative stress in L-NAME rats. It suppressed high levels of serum angiotensin-converting enzyme activity, plasma angiotensin II, and cardiac angiotensin II type 1 receptor, NADPH oxidases 2, nuclear factor-kappa B, and tumor necrosis factor-alpha expression. The CT extract, therefore, partially prevented L-NAME-induced hypertension and cardiovascular alterations in rats. These effects might be related to a reduction in the oxidative stress and renin-angiotensin system activation due to L-NAME in rats.

Genistein Prevents Nitric Oxide Deficiency-Induced Cardiac Dysfunction and Remodeling in Rats

Genistein is an isoflavone found in soybeans. This study evaluates the protective effects of genistein on N^ω-nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertension, cardiac remodeling, and dysfunction in rats. Male Wistar rats were treated with L-NAME 40 mg/kg/day together for 5 weeks, with or without genistein at a dose of 40 or 80 mg/kg/day or lisinopril 5 mg/kg/day (n = 8 per group). Genistein prevented L-NAME-induced hypertension in rats. Increases in the left ventricular weight, metalloproteinase-2, metalloproteinase-9, and collagen type I intensity were observed in L-NAME rats, and these changes were attenuated in the genistein-treated group. Genistein reduced circulating angiotensin-converting enzyme activity and angiotensin II concentrations in L-NAME rats. L-NAME increased plasma and cardiac malondialdehyde and vascular superoxide generations, as well as reductions of serum and cardiac catalase activities in rats. Plasma nitrate/nitrite were protected in the genistein-treated group. Genistein prevented the L-NAME-induced overexpression of angiotensin II receptor type I (AT₁R), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit 2 (gp91^phox), and transforming growth factor beta I (TGF-β1) in hypertensive rats. In conclusion, genistein exhibited a cardioprotective effect in hypertensive rats in this study. The molecular mechanisms might be mediated by suppression of oxidative stress through the Ang II/AT₁R/NADPH oxidase/TGF-β1 signaling pathway.

Nobiletin alleviates high-fat diet-induced nonalcoholic fatty liver disease by modulating AdipoR1 and gp91phox expression in rats

Nobiletin, one of the polymethoxylated flavonoids isolated from citrus peels, is reported to possess various biological activities. The current study investigates the effect and possible mechanisms of nobiletin on nonalcoholic fatty liver disease (NAFLD) in high-fat diet (HFD)-fed rats. Male Sprague-Dawley rats were administrated with HFD and fructose (15%) in drinking water for 16 weeks to induce NAFLD. HFD-fed rats were treated with nobiletin (20 or 40 mg/kg/day) or vehicle for the last 4 weeks. Treatment of HFD-fed rats with nobiletin significantly reduced systolic blood pressure, adiposity, hyperlipidemia, insulin resistance, hepatic lipids content, NAFLD activity score and liver fibrosis. Nobiletin significantly increased plasma adiponectin levels, together with up-regulation of liver adiponectin receptor 1 (AdipoR1) expression. Additionally, decreased malondialdehyde levels and increased superoxide dismutase activity in plasma and hepatic tissue, consistent with down-regulation of liver NADPH oxidase subunit gp91phox expression, were also observed after nobiletin treatment. Furthermore, high dose of nobiletin exhibited higher therapeutic effect as a compared to low dose. These findings suggest that nobiletin alleviates HFD-induced NAFLD and metabolic dysfunction in rats. There might be an association between the observed inhibitory effect of nobiletin on NAFLD and modulation of AdipoR1 and gp91phox.

Cratoxylum formosum dyer extract alleviates testicular damage in hypertensive rats

The effects of a Cratoxylum formosum (Jack) Dyer ssp. (CF) extract on testicular damage were assessed in hypertensive rats. N^ω -nitro-L-arginine methyl ester hydrochloride (L-NAME; 40 mg kg^-1  day^-1 ) was administered for 5 weeks to induce hypertension in male Sprague-Dawley rats, and treated with CF extract (100, 300 or 500 mg kg^-1  day^-1 ) or sildenafil (5 mg kg^-1  day^-1 ) during the final 2 weeks (n = 8/group). Biochemical components of the CF extract were identified and mainly contained phenolic compounds. The CF extract significantly reduced systolic blood pressure and alleviated impaired sperm quality and seminiferous tubular morphology in hypertensive rats. CF extract restored reduced serum testosterone and protein expression of steroidogenic acute regulatory protein (StAR), nuclear factor erythroid-related factor 2 (Nrf2), and haem oxygenase 1 (HO-1) in L-NAME rats. Hypertensive rats presented decreased antioxidant enzyme activities, and increased testicular and plasma malondialdehyde (MDA) levels and superoxide production, all of which were normalised by CF extract. Furthermore, endothelial nitric oxide synthase (eNOS) expression in testicular tissue and plasma nitrate/nitrite levels were restored in hypertensive rats administered CF extract. Conclusion: CF extract alleviated testicular damage in hypertensive rats. Potential molecular mechanisms may involve suppression of oxidative stress and restoration of StAR, Nrf2, HO-1 and eNOS expression in hypertensive rats.

Hesperidin inhibits L-NAME-induced vascular and renal alterations in rats by suppressing the renin-angiotensin system, transforming growth factor-β1, and oxidative stress

The protective effect of hesperidin on vascular and renal alterations and possible underlying mechanisms involved in N^ω -nitro-L-arginine methyl ester hydrochloride (L-NAME)-induced hypertensive rats were investigated in this study. Male Sprague-Dawley rats were administered L-NAME (40 mg/kg/day), L-NAME plus hesperidin (30 mg/kg/day), and L-NAME plus captopril (2.5 mg/kg/day) for 5 weeks. Hesperidin and captopril significantly prevented L-NAME-induced hypertension, vascular and renal dysfunction, intrarenal artery remodelling, glomerular extracellular matrix accumulation, and renal fibrosis. The preventive treatment with hesperidin and captopril also significantly decreased serum angiotensin-converting enzyme activity and plasma transforming growth factor-β1 (TGF-β1) levels and downregulated angiotensin II receptor type I and TGF-β1 protein expression in the kidneys. In addition, decreased malondialdehyde levels and increased superoxide dismutase activity in the plasma and kidney were observed after co-treatment with hesperidin or captopril. These findings suggest that hesperidin inhibits L-NAME-induced vascular and renal alterations in rats. The possible mechanism may be related to the suppression of the activation of the renin-angiotensin system and expression of TGF-β1, and reduction of oxidative stress.

Syzygium gratum Extract Alleviates Vascular Alterations in Hypertensive Rats

Background and Objectives: Syzygium gratum (SG) is a local vegetable and widely consumed in Thailand. Previously, a strong antioxidative effect of SG extract has been reported. The effects of SG extract on hypertension have remained unknown. The effect of SG aqueous extract on blood pressure and vascular changes were examined in L-NAME-induced hypertensive rats (LHR), and its potential active constituents were also explored. Materials and Methods: Male Sprague Dawley rats were allocated to control, L-NAME (40 mg/kg/day), L-NAME + SG (100, 300, 500 mg/kg/day), or captopril (5 mg/kg/day) groups. The components of SG extract were analyzed. Results: The analysis of aqueous SG extract was carried out using HPLC-Mass spectroscopy, and phenolic compounds could be identified as predominant components which might be responsible for its antihypertensive effects observed in the LHR model (p < 0.05). Additionally, SG extract also improved vascular responses to acetylcholine and decreased vascular remodeling in LHR (p < 0.05). Enhancements of eNOS expression and plasma nitric oxide metabolite levels, and attenuation of angiotensin converting enzyme (ACE) activity and plasma angiotensin II levels were observed in the LHR group treated with SG. Moreover, SG exhibited strong antioxidant activities by reducing vascular superoxide generation and systemic malondialdehyde in LHRs. Captopril suppressed high blood pressure and alleviated vascular changes and ACE activity in LHRs, similar to those of the SG extract (p < 0.05). Conclusion: Our results suggest that the SG extract exhibited antihypertensive effects, which is relevant to alleviation of vascular dysfunction and vascular remodeling of LHRs. These effects might be mediated by phenolic compounds to inhibit ACE activity and scavenge reactive oxygen species in LHR.

Tangeretin mitigates l-NAME-induced ventricular dysfunction and remodeling through the AT1R/pERK1/2/pJNK signaling pathway in rats

Tangeretin alleviates ventricular alterations in l-NAME hypertensive rats.

Nobiletin alleviates vascular alterations through modulation of Nrf-2/HO-1 and MMP pathways in l-NAME induced hypertensive rats

Nobiletin alleviates l-NAME-induced vascular dysfunction and remodeling and superoxide production in rats.

Hesperidin Prevents Nitric Oxide Deficiency-Induced Cardiovascular Remodeling in Rats via Suppressing TGF-β1 and MMPs Protein Expression

Hesperidin is a major flavonoid isolated from citrus fruits that exhibits several biological activities. This study aims to evaluate the effect of hesperidin on cardiovascular remodeling induced by n-nitro l-arginine methyl ester (l-NAME) in rats. Male Sprague-Dawley rats were treated with l-NAME (40 mg/kg), l-NAME plus hesperidin (15 mg/kg), hesperidin (30 mg/kg), or captopril (2.5 mg/kg) for five weeks (n = 8/group). Hesperidin or captopril significantly prevented the development of hypertension in l-NAME rats. l-NAME-induced cardiac remodeling, i.e., increases in wall thickness, cross-sectional area (CSA), and fibrosis in the left ventricular and vascular remodeling, i.e., increases in wall thickness, CSA, vascular smooth muscle cells, and collagen deposition in the aorta were attenuated by hesperidin or captopril. These were associated with reduced oxidative stress markers, tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta 1 (TGF-β1), and enhancing plasma nitric oxide metabolite (NOx) in l-NAME treated groups. Furthermore, up-regulation of tumor necrosis factor receptor type 1 (TNF-R1) and TGF- β1 protein expression and the overexpression of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) was suppressed in l-NAME rats treated with hesperidin or captopril. These data suggested that hesperidin had cardioprotective effects in l-NAME hypertensive rats. The possible mechanism may involve antioxidant and anti-inflammatory effects.

Hesperidin Suppresses Renin-Angiotensin System Mediated NOX2 Over-Expression and Sympathoexcitation in 2K-1C Hypertensive Rats

Hesperidin, a flavonoid derived from citrus fruits, possesses several beneficial effects including anti-oxidation and anti-inflammation. The aim of this study was to investigate the effects of hesperidin on the renin-angiotensin system (RAS) cascade that mediated oxidative stress and sympathoexcitation in two-kidney, one-clipped (2K-1C) hypertensive rats. 2K-1C hypertension was induced in male Sprague-Dawley rats. Hypertensive rats were treated with hesperidin at 20[Formula: see text]mg/kg or 40[Formula: see text]mg/kg or losartan at 10[Formula: see text]mg/kg beginning at three weeks after surgery and then continued for four weeks ([Formula: see text]/group). Hesperidin reduced blood pressure in a dose-dependent manner in hypertensive rats compared to untreated rats ([Formula: see text]). Increased plasma angiotensin converting enzyme (ACE) activity and angiotensin II levels, as well as, upregulated AT₁ receptor protein expression in aortic tissues were attenuated in hypertensive rats treated with hesperidin. Hesperidin suppressed oxidative stress markers and NADPH oxidase over-expression, and restored plasma nitric oxide metabolites in 2K-1C rats. This was associated with improvement of the vascular response to acetylcholine in isolated mesenteric vascular beds and aortic rings from 2K-1C rats treated with hesperidin ([Formula: see text]). Enhancement of nerve-mediated vasoconstriction related to high plasma noradrenaline in the 2K-1C group was alleviated by hesperidin treatment ([Formula: see text]). Furthermore, losartan exhibited antihypertensive effects by suppressing the RAS cascade and oxidative stress and improved vascular dysfunction observed in 2K-1C rats ([Formula: see text]). Based on these results, it can be presumed that hesperidin is an antihypertensive agent. Its antihypertensive action might be associated with reducing RAS cascade-induced NOX2 over-expression and sympathoexcitation in 2K-1C hypertensive rats.

Effect of asiatic acid on the Ang II-AT1R-NADPH oxidase-NF-κB pathway in renovascular hypertensive rats

Asiatic acid, a triterpenoid compound derived from Centella asiatica, has been demonstrated to have antioxidant and anti-inflammatory effects. The present study evaluated the effects of asiatic acid on hemodynamic alterations, renin-angiotensin system (RAS), oxidative stress, and inflammation in 2K-1C hypertensive rats. Renovascular hypertension was induced in male Sprague-Dawley rats and treated with vehicle, asiatic acid (30 mg/kg/day), or captopril (5 mg/kg/day) for 4 weeks. We observed that 2K-1C hypertensive rats exhibited hemodynamic alterations such as high blood pressure, heart rate, hindlimb vascular resistance, and low hindlimb blood flow. Signs of RAS activation, such as increased plasma angiotensin II and serum angiotensin-converting enzyme activity, enhanced AT₁R protein expression, and suppressed AT₂R expression was observed in 2K-1C hypertensive rats. Overproduction of vascular superoxide, high levels of plasma MDA, low levels of plasma nitric oxide metabolites (NOx), and upregulation of gp91^phox protein expression were observed in hypertensive rats. Furthermore, inflammation was observed in hypertensive rats, as evidenced by increased plasma TNF-α, NF-κB, and phospho-NF-κB protein expression. Asiatic acid or captopril alleviated hemodynamic alterations, RAS activation, oxidative stress, and inflammation in 2K-1C hypertensive rats. These findings indicate that asiatic acid is an antihypertensive agent that ameliorates hemodynamic alterations in 2K-1C hypertensive rats. This effect may involve one or both of the following mechanisms: the direct effect of asiatic acid on RAS activation, oxidative stress and inflammation, and/or asiatic acid acting as an ACE inhibitor agent to inhibit the Ang II-AT₁R-NADPH oxidase-NF-κB pathway.

Bacopa monnieri and its constituents is hypotensive in anaesthetized rats and vasodilator in various artery types

ETHNOPHARMACOLOGICAL RELEVANCE

Bacopa monnieri (Brahmi) provides traditional cognitive treatments possibly reflecting improved cerebral hemodynamics. Little is known about the cardiovascular actions of Brahmi. We sought to assess its effects on blood pressure and on isolated arteries, thus providing insights to clinical applications.

MATERIALS AND METHODS

Intravenous Brahmi (20-60 mg/kg) was tested on arterial blood pressure and heart rate of anaesthetized rats. In vitro vasorelaxation was assessed in arteries, with and without blockers of nitric oxide synthase (L-NAME), cyclooxygenase (indomethacin), and mechanical de-endothelialisation. The effects of Brahmi on Ca(2+) influx and release from stores were investigated.

RESULTS

Intravenous Brahmi extract (20-60 mg/kg) decreased systolic and diastolic pressures without affecting heart rate. Brahmi evoked relaxation in isolated arteries in order of potency: basilar (IC50=102 ± 16 μg/ml)>mesenteric (171 ± 31)>aortae (213 ± 68)>renal (IC50=375 ± 51)>tail artery (494 ± 93)>femoral arteries (>1,000 μg/ml). Two saponins, bacoside A3 and bacopaside II, had similar vasodilator actions (IC50=8.3 ± 1.7 and 19.5 ± 6.3 μM). In aortae, without endothelium or in L-NAME (10-4M), Brahmi was less potent (IC50=213 ± 68 to 2170 ± 664 and 1192 ± 167 μg/ml, respectively); indomethacin (10-5M) was ineffective. In tail artery, Brahmi inhibited K(+)-depolarization induced Ca(2+) influx and Ca(2+) release from the sarcoplasmic reticulum by phenylephrine (10-5M) or caffeine (20mM).

CONCLUSIONS

Brahmi reduces blood pressure partly via releasing nitric oxide from the endothelium, with additional actions on vascular smooth muscle Ca(2+) homeostasis. Some Brahmi ingredients could be efficacious antihypertensives and the vasodilation could account for some medicinal actions.

Cancer survival in Chiang Mai, Thailand, 1993-1997

The Chiang Mai tumour registry was established in 1978 as a hospital-based cancer registry, and population-based cancer registration started in 1986, with retrospective data collection on cancer incidence and mortality since 1983. Registration of cases is done by active methods. Data on survival for 36 cancer sites or types registered during 1993-1997 are reported here. Follow-up has been carried out predominantly by active methods, with median follow-up ranging between 1-39 months for different cancers. The proportion of histologically verified diagnosis for various cancers ranged between 28-100%; death certificate only (DCO) cases comprised 0-56%; 33-92% of total registered cases were included for survival analysis. Complete followup at five years ranged from 59-100% for different cancers. The 5-year age-standardized relative survival rates was the highest for Hodgkin lymphoma (70%) followed by thyroid (65%), cervix (57%), breast (56%) and corpus uteri (49%). The 5-year relative survival by age group showed either an inverse relationship or was fluctuating. An overwhelmingly high proportion of cases were diagnosed with a regional spread of disease, ranging between 44-82% for different cancers and survival decreased with increasing extent of disease for all cancers studied.