Supplementation with rice bran hydrolysates reduces oxidative stress and improves lipid profiles in adult dogs.

Oxidative stress is defined as an imbalance between reactive oxygen species (ROS) production and antioxidant defense mechanisms of the body. An overproduction of ROS leads to lipid and protein oxidation, injuring the cells both in normal and pathological conditions. Rice bran protein hydrolysates (RBH) has potent antioxidant, anti-inflammatory, anti-angiotensin converting enzyme (ACE) and hypolipidemic effects. Little is known, however, about the effects of RBH in dogs. The present study evaluated the antioxidative, anti-ACE and metabolic effects of RBH in adult dogs. Eighteen adult dogs were divided into 2 groups: control (n=7) and RBH supplemented groups (n=11), received a diet with the same nutritional compositions. The RBH supplemented group was fed with RBH 500 mg/kg body weight (BW) mixed with food for 30 days. BW, blood glucose, lipid profiles, liver enzymes, electrocardiography (ECG), plasma ACE activity, oxidative stress and antioxidant biomarkers were determined on day 0 and day 30 of supplementation periods. Results showed that RBH decreased oxidative stress and increased antioxidant biomarkers by significantly reducing plasma malondialdehyde (MDA) and protein carbonyl, enhanced blood glutathione (GSH) and improved the GSH redox ratio. Moreover, decreased LDL-C and increased HDL-C levels were found after RBH supplementation whereas BW, blood glucose, liver enzymes, plasma ACE activity, plasma catalase (CAT) and superoxide dismutase (SOD) activity and cardiac function were not significantly changed. These results suggest that RBH may help to lower the risk of oxidative stress and dyslipidemia in adult dogs.

Sang-Yod rice bran hydrolysates alleviate hypertension, endothelial dysfunction, vascular remodeling, and oxidative stress in nitric oxide deficient hypertensive rats

Objective: To evaluate the potential therapeutic effect of Sang-Yod rice bran hydrolysates (SRH) and in combination with lisinopril against hypertension, endothelial dysfunction, vascular remodeling, and oxidative stress in rats with nitric oxide deficiency-induced hypertension. Methods: Hypertension was induced in male Sprague-Dawley rats by administration of a nitric oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME) in drinking water for 6 weeks. Hypertensive rats were administered daily with SRH (500 mg/kg/day), lisinopril (1 mg/kg/day), or the combination of SRH and lisinopril by gastric lavage for the last 3 weeks of L-NAME treatment. Hemodynamic status, vascular reactivity to vasoactive agents, and vascular remodeling were assessed. Blood and aortic tissues were collected for measurements of oxidative stress markers, plasma angiotensin-converting enzyme (ACE) activity, plasma angiotensinⅡ, and protein expression. Results: L-NAME induced remarkable hypertension and severe oxidative stress, and altered contents of smooth muscle cells, elastin, and collagen of the aortic wall. SRH or lisinopril alone reduced blood pressure, restored endothelial function, decreased plasma ACEs and angiotensinⅡlevels, alleviated oxidant markers and glutathione redox status, and restored the vascular structure. The effects were associated with increased expression of endothelial nitric oxide synthase and decreased expression of gp91phox and AT1R expression. The combination of SRH and lisinopril was more effective than monotherapy. Conclusions: SRH alone or in combination with lisinopril exert an antihypertensive effect and improve endothelial function and vascular remodeling through reducing oxidative stress and suppressing elevated renin-angiotensin system.

Protective effects of rice bran hydrolysates on heart rate variability, cardiac oxidative stress, and cardiac remodeling in high fat and high fructose diet-fed rats

Objective: To examine the ameliorative effect of rice bran hydrolysates (RBH) on metabolic disorders, cardiac oxidative stress, heart rate variability (HRV), and cardiac structural changes in high fat and high fructose (HFHF)-fed rats.Methods: Male Sprague-Dawley rats were daily fed either standard chow diet with tap water or an HFHF diet with 10％ fructose in drinking water over 16 weeks. RBH (500 and 1000 mg/kg/day) was orally administered to the HFHF-diet-fed rats during the last 6 weeks of the study period. At the end of the treatment, metabolic parameters, oxidative stress, HRV, and cardiac structural changes were examined. Results: RBH administration significantly ameliorated metabolic disorders by improving lipid profiles, insulin sensitivity, and hemodynamic parameters. Moreover, RBH restored HRV, as evidenced by decreasing the ratio of low-frequency to high-frequency power of HRV, a marker of autonomic imbalance. Cardiac oxidative stress was also mitigated after RBH supplementation by decreasing cardiac malondialdehyde and protein carbonyl, upregulating eNOS expression, and increasing catalase activity in the heart. Furthermore, RBH mitigated cardiac structural changes by reducing cardiac hypertrophy and myocardial fibrosis in HFHF-diet-fed rats. Conclusions: The present findings suggest that consumption of RBH may exert cardioprotective effects against autonomic imbalances, cardiac oxidative stress, and structural changes in metabolic syndrome.

Virgin rice bran oil alleviates hypertension through the upregulation of eNOS and reduction of oxidative stress and inflammation in L-NAME-induced hypertensive rats.

OBJECTIVE: Endothelial dysfunction associated with reduction in nitric oxide (NO) bioavailability plays an important role in development of hypertension. Consumption of a diet rich in antioxidants appears to lower the risk for hypertension. Virgin rice bran oil (VRBO) possesses antioxidant, anti-inflammatory, and hypocholesterolemic activities. However, to our knowledge, the antihypertensive effect of VRBO has not been investigated. The aim of this study was to examine the antihypertensive effect of VRBO in Nω-nitro-l-arginine methyl ester (L-NAME)-induced hypertensive rats and its underlying mechanisms. METHODS: Hypertension was induced in rats by administration of L-NAME, after which VRBO, lisinopril (Lis), or VRBO + Lis was administered. Studies were then conducted on the hemodynamics of vascular responses to vasoactive substances, plasma angiotensin-converting enzyme (ACE), plasma nitrate/nitrite, oxidative stress, and inflammatory markers. RESULTS: L-NAME administration induced hemodynamic changes including elevation of blood pressure, increased peripheral vascular resistance, and endothelial dysfunction. Reduction in plasma nitrate/nitrite, overproduction of vascular superoxide, and increases in plasma ACE, malondialdehyde, protein carbonyl, and plasma tumor necrosis factor-α were observed in L-NAME hypertensive rats. The changes were associated with a marked decrease in endothelial NO synthase expression, increased expression of gp91phoxand vascular cell adhesion molecule-1, and activation of nuclear factor-κB in aortic tissues. Administration of either VRBO or Lis significantly mitigated all of these deleterious effects. The combination of VRBO and Lis was more effective than either treatment alone. CONCLUSIONS: The antihypertensive effect of VRBO may be mediated by restoration of hemodynamics, increased NO bioavailability, and alleviation of oxidative stress and inflammation. VRBO has an additive effect on antihypertensive medication.

Antihypertensive Effect and Safety Evaluation of Rice Bran Hydrolysates from Sang-Yod Rice.

Rice bran hydrolysates contain highly nutritional proteins and beneficial phytochemicals. Sang-Yod rice bran hydrolysates (SRH) extracted from red pigmented rice is a rich source of nutrients and phenolic compounds. The present study evaluated the antihypertensive effect of SRH and its safety in Sprague-Dawley rats. Hypertension was induced in male rats by administration of L-NAME (50 mg/kg/day) in drinking water for three weeks, and the antihypertensive effect of SRH was evaluated. Treatment of SRH (250 or 500 mg/kg) significantly reduced arterial blood pressure and improved hemodynamic parameters. The antihypertensive effect was associated with decreased oxidative stress, suppressed p47phox NADPH oxidase expression, increased nitric oxide bioavailability and decreased angiotensin II level and ACE activity. The SRH was shown to be safe after feeding male and female rats with a rodent diet containing 1.5% SRH for 90 days. Overall, these findings suggest that SRH is safe and may help to prevent hypertension.

Rice bran protein hydrolysates reduce arterial stiffening, vascular remodeling and oxidative stress in rats fed a high-carbohydrate and high-fat diet.

PURPOSE: Rice bran protein hydrolysates (RBPH) contain highly nutritional proteins and antioxidant compounds which show benefits against metabolic syndrome (MetS). Increased arterial stiffness and the components of MetS have been shown to be associated with an increased risk of cardiovascular disease. This study aimed to investigate whether RBPH could alleviate the metabolic disorders, arterial stiffening, vascular remodeling, and oxidative stress in rats fed a high-carbohydrate and high-fat (HCHF) diet. METHODS: Male Sprague-Dawley rats were fed either a standard chow and tap water or a HCHF diet and 15 % fructose solution for 16 weeks. HCHF rats were treated orally with RBPH (250 or 500 mg/kg/day) for the final 6 weeks of the experimental period. RESULTS: Rats fed with HCHF diet had hyperglycemia, insulin resistance, dyslipidemia, hypertension, increased aortic pulse wave velocity, aortic wall hypertrophy and vascular remodeling with increased MMP-2 and MMP-9 expression. RBPH supplementation significantly alleviated these alterations (P < 0.05). Moreover, RBPH reduced the levels of angiotensin-converting enzyme (ACE) and tumor necrosis factor-alpha in plasma. Oxidative stress was also alleviated after RBPH treatment by decreasing plasma malondialdehyde, reducing superoxide production and suppressing p47phox NADPH oxidase expression in the vascular tissues of HCHF rats. RBPH increased plasma nitrate/nitrite level and up-regulated eNOS expression in the aortas of HCHF-diet-fed rats, indicating that RBPH increased NO production. CONCLUSION: RBPH mitigate the deleterious effects of HCHF through potential mechanisms involving enhanced NO bioavailability, anti-ACE, anti-inflammatory and antioxidant properties. RBPH could be used as dietary supplements to minimize oxidative stress and vascular alterations triggered by MetS.

Ferulic Acid Alleviates Changes in a Rat Model of Metabolic Syndrome Induced by High-Carbohydrate, High-Fat Diet.

Metabolic syndrome is a cluster of metabolic abnormalities characterized by obesity, insulin resistance, hypertension and dyslipidemia. Ferulic acid (FA) is the major phenolic compound found in rice oil and various fruits and vegetables. In this study, we examined the beneficial effects of FA in minimizing insulin resistance, vascular dysfunction and remodeling in a rat model of high-carbohydrate, high-fat diet-induced metabolic changes, which is regarded as an analogue of metabolic syndrome (MS) in man. Male Sprague-Dawley rats were fed a high carbohydrate, high fat (HCHF) diet and 15% fructose in drinking water for 16 weeks, where control rats were fed with standard chow diet and tap water. FA (30 or 60 mg/kg) was orally administered to the HCHF and control rats during the last six weeks of the study. We observed that FA significantly improved insulin sensitivity and lipid profiles, and reduced elevated blood pressure, compared to untreated controls (p < 0.05). Moreover, FA also improved vascular function and prevented vascular remodeling of mesenteric arteries. The effects of FA in HCHF-induced MS may be realized through suppression of oxidative stress by down-regulation of p47phox, increased nitric oxide (NO) bioavailability with up-regulation of endothelial nitric oxide synthase (eNOS) and suppression of tumor necrosis factor-α (TNF-α). Our results suggest that supplementation of FA may have health benefits by minimizing the cardiovascular complications of MS and alleviating its symptoms.