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Obese Zucker Rats (obese + zucker_rat)

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Medical Sciences100%

Selected Abstracts

Progressive Renal Vascular Proliferation and Injury in Obese Zucker Rats

MICROCIRCULATION, Issue 4 2010
RADU ILIESCU
Microcirculation (2010) 17, 250,258. doi: 10.1111/j.1549-8719.2010.00020.x Abstract Objective:, Obesity, an independent risk factor for chronic kidney disease, may induce renal injury by promoting inflammation. Inflammatory cytokines can induce neovascularization in different organs, including the kidneys. However, whether obesity triggers renal neovascularization and, if so, its effect on renal function has never been investigated. Methods:, Blood pressure, proteinuria, and glomerular filtration rate (GFR) were measured in vivo. Renal microvascular (MV) architecture was studied by 3D micro-CT in lean and obese Zucker rats (LZR and OZR, n = 7/group) at 12, 22, and 32 weeks of age. Renal inflammation was assessed by quantifying interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and ED-1 expression, as renal fibrosis in trichrome-stained cross-sections. Results:, Mild inflammation and lower GFR was only observed in younger OZR, without renal fibrosis or changes in MV density. Interestingly, renal MV density increased in OZR at 32 weeks of age, accompanied by pronounced increase in renal IL-6 and TNF-alpha, ED-1+ cells, proteinuria, decreased GFR, and fibrosis. Conclusions:, This study shows increased renal cortical vascularization in experimental obesity, suggesting neovascularization as an evolving process as obesity progresses. Increased renal vascularization, possibly triggered by inflammation, may reflect an initially compensatory mechanism in obesity. However, increased inflammation and inflammatory-induced neovascularization may further promote renal injury as obesity advances. [source]

KATP -mediated Vasodilation is Impaired in Obese Zucker Rats

MICROCIRCULATION, Issue 6 2008
BENJAMIN L. HODNETT
ABSTRACT Objective: Skeletal muscle blood flow during exercise is impaired in obesity. We tested the hypothesis that the attenuated vasodilation in skeletal muscle arterioles of obese Zucker rats (OZR) is due to altered KATP channel-mediated vasodilation. Materials and Methods: KATP channel function was determined in isolated skeletal muscle arterioles in response to the KATP opener cromakalim (0.1,10 , M) during normal myogenic tone and , -adrenergic-mediated tone (0.1 , M phenylephrine). The spinotrapezius muscle was prepared and the vasodilatory responses to muscle stimulation or iloprost (0.028,2.8 , M) were observed before and after the application of the KATP inhibitor, glibenclamide (10 , M). Channel subunit expression was determined by using western blot analyses. Results: Cromakalim concentration-response curves were shifted in OZR as compared to lean controls. OZR exhibited impaired functional and iloprost-induced vasodilation as compared to the lean controls. Glibenclamide inhibited the functional and iloprost-induced dilation in the lean rats with no effects in the obese animals. Channel subunit expression was similar in femoral arteries. Conclusion:The impaired functional vasodilation in the OZR is associated with altered KATP channel sensitivity. [source]

Effects of microcrystalline plant sterol suspension and a powdered plant sterol supplement on hypercholesterolemia in genetically obese Zucker rats

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2003
Jari Summanen
ABSTRACT Because dietary fat appears to be an effective vehicle for dispensing plant sterols into the diet, a special plant-sterol-containing ingredient has recently been developed. This ingredient is a plant sterol suspension in oil in which the sterols are in microcrystalline form. The objective of the present study was to analyse the cholesterol-lowering effects and safety of two different plant sterol preparations, an orally administered microcrystalline plant sterol suspension (MPS) in rapeseed oil and a powdered plant sterol supplement, in obese Zucker rats. Dietary plant sterol supplements (0.5%, w/w) were given concurrently with a high cholesterol diet (HCD, 1% cholesterol and 18% fat, w/w). No significant changes in serum triglyceride, blood glucose, serum glutamate oxaloacetic transaminase and glutamic pyruvic transaminase values or body and liver weights were observed. The powdered plant sterol supplement lowered the serum cholesterol by 25% (P< 0.05) and the MPS diet by 35% (P< 0.001) compared with HCD by the end of the 12-week experiment. Interestingly, the plant sterol supplements also produced a marked reduction in serum ubiquinone levels, suggesting a possible effect on isoprene synthesis. Unlike the powdered plant sterol, both MPS and plain rape-seed oil decreased the serum baseline diene conjugation values, suggesting that they protect against oxidative stress-induced lipid peroxidation in rats. This lipid peroxidation diminishing effect is probably due to some antioxidative components in rapeseed oil. These findings indicate that an unesterified plant sterol, such as the microcrystalline suspension in oil, effectively prevents cholesterol absorption in obese Zucker rats. [source]

Progressive Renal Vascular Proliferation and Injury in Obese Zucker Rats

MICROCIRCULATION, Issue 4 2010
RADU ILIESCU
Microcirculation (2010) 17, 250,258. doi: 10.1111/j.1549-8719.2010.00020.x Abstract Objective:, Obesity, an independent risk factor for chronic kidney disease, may induce renal injury by promoting inflammation. Inflammatory cytokines can induce neovascularization in different organs, including the kidneys. However, whether obesity triggers renal neovascularization and, if so, its effect on renal function has never been investigated. Methods:, Blood pressure, proteinuria, and glomerular filtration rate (GFR) were measured in vivo. Renal microvascular (MV) architecture was studied by 3D micro-CT in lean and obese Zucker rats (LZR and OZR, n = 7/group) at 12, 22, and 32 weeks of age. Renal inflammation was assessed by quantifying interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and ED-1 expression, as renal fibrosis in trichrome-stained cross-sections. Results:, Mild inflammation and lower GFR was only observed in younger OZR, without renal fibrosis or changes in MV density. Interestingly, renal MV density increased in OZR at 32 weeks of age, accompanied by pronounced increase in renal IL-6 and TNF-alpha, ED-1+ cells, proteinuria, decreased GFR, and fibrosis. Conclusions:, This study shows increased renal cortical vascularization in experimental obesity, suggesting neovascularization as an evolving process as obesity progresses. Increased renal vascularization, possibly triggered by inflammation, may reflect an initially compensatory mechanism in obesity. However, increased inflammation and inflammatory-induced neovascularization may further promote renal injury as obesity advances. [source]

KATP -mediated Vasodilation is Impaired in Obese Zucker Rats

MICROCIRCULATION, Issue 6 2008
BENJAMIN L. HODNETT
ABSTRACT Objective: Skeletal muscle blood flow during exercise is impaired in obesity. We tested the hypothesis that the attenuated vasodilation in skeletal muscle arterioles of obese Zucker rats (OZR) is due to altered KATP channel-mediated vasodilation. Materials and Methods: KATP channel function was determined in isolated skeletal muscle arterioles in response to the KATP opener cromakalim (0.1,10 , M) during normal myogenic tone and , -adrenergic-mediated tone (0.1 , M phenylephrine). The spinotrapezius muscle was prepared and the vasodilatory responses to muscle stimulation or iloprost (0.028,2.8 , M) were observed before and after the application of the KATP inhibitor, glibenclamide (10 , M). Channel subunit expression was determined by using western blot analyses. Results: Cromakalim concentration-response curves were shifted in OZR as compared to lean controls. OZR exhibited impaired functional and iloprost-induced vasodilation as compared to the lean controls. Glibenclamide inhibited the functional and iloprost-induced dilation in the lean rats with no effects in the obese animals. Channel subunit expression was similar in femoral arteries. Conclusion:The impaired functional vasodilation in the OZR is associated with altered KATP channel sensitivity. [source]

Administration of Cyperus rotundus tubers extract prevents weight gain in obese Zucker rats

PHYTOTHERAPY RESEARCH, Issue 8 2007
Bernard Lemaure
Abstract Cyperus rotundus L. (Cyperaceae; C. rotundus) is an Indian medicinal plant demonstrated to exert multiple health benefits. The purpose of the present study was to test the biological efficacy of C. rotundus tubers extract on weight control in obese Zucker rats. It was demonstrated that administration of 45 or 220 mg/kg/day of C. rotundus tubers hexane extract for 60 days in Zucker rats induced a significant reduction in weight gain without affecting food consumption or inducing toxicity. In vitro, 250 µg/mL of this extract was able to stimulate lipolysis in 3T3-F442 adipocytes suggesting that this medicinal plant contains activators of , -adrenoreceptors (AR). The binding assay performed on the rat ,3-AR isoform, known to induce thermogenesis, demonstrated that C. rotundus tubers extract can consistently and effectively bind to this receptor. These data suggest that the effect on weight gain exerted by C. rotundus tubers extract may be mediated, at least partially, through the activation of the ,3-AR. In conclusion, C. rotundus tubers extract prove to be a new herbal supplement for controlling body weight preferentially in ,3-AR sensitive species. Copyright © 2007 John Wiley & Sons, Ltd. [source]