Fructose-fed Rats Research Articles

Magnolol Inhibits High Fructose-Induced Podocyte Inflammation via Downregulation of TKFC/Sp1/HDAC4/Notch1 Activation

Background/Objectives: High fructose has been implicated as an important trigger of kidney inflammation in patients and experimental models. Magnolol, isolated from Magnolia officinalis, has an anti-inflammatory effect, but its protective role in podocytes remains underexplored. This study explored the protective effects and underlying mechanism of magnolol against high fructose-induced podocyte inflammation. Methods: The effects of magnolol on high fructose-induced podocyte inflammation were assessed in male Sprague Dawley rats administered 10% (w/v) fructose water for 12 weeks and heat-sensitive human podocyte cell lines (HPCs) exposed to 5 mM fructose. Podocyte foot processes were examined using transmission electron microscopy. The expression levels of nephrin, podocin, tumor necrosis factor-α (TNF-α), Notch1 intracellular domain (NICD1), triokinase/FMN cyclase (TKFC), specificity protein 1 (Sp1) and histone deacetylase 4 (HDAC4) were determined by Western blot, immunofluorescence and real-time quantitative polymerase chain reaction (qRT-PCR). The chromatin immunoprecipitation (ChIP) assay was performed to evaluate the interaction between Sp1 and the promoter region of HDAC4. Results: Magnolol mitigated the impairment of glomerular filtration function in high fructose-fed rats. Besides, it significantly alleviated the inflammatory responses in glomeruli and HPCs, evidenced by decreased protein levels of TNF-α and NICD1. Increased protein levels of TKFC, Sp1 and HDAC4 were observed in high fructose-stimulated HPCs and rat glomeruli. TMP195, an HDAC4 inhibitor, reduced TNF-α and NICD1 protein levels in high fructose-exposed HPCs. The increased Sp1 was shown to associate with the promoter region of HDAC4, promoting HDAC4 protein expression in high fructose-exposed HPCs. The knockdown of TKFC in HPCs by TKFC siRNA decreased Sp1, HDAC4 and NICD1 protein levels, alleviating podocyte inflammatory response. Furthermore, magnolol inhibited TKFC/Sp1/HDAC4/Notch1 activation in vivo and in vitro. Conclusions: Magnolol attenuated high fructose-induced podocyte inflammation possibly through the suppression of TKFC/Sp1/HDAC4/Notch1 activation, providing new evidence for its potential role in podocyte protection.

Siwu tablet attenuates high fructose-induced glomerular podocyte senescence in rats through increasing Nup155 to promote INO80 mRNA nuclear export

Ethnopharmacological relevanceSiwu tablet (SWT), derived from a traditional Chinese medicinal formula named Siwu decoction, is widely used for blood deficiency syndrome. Siwu decoction and its derived formulas have been proven to improve renal anemia and prevent senescence. Whether SWT prevents glomerular podocyte senescence and the underlying molecular mechanism remains unknow. Aim of the studyTo elucidate the protective effect and possible mechanism of SWT on glomerular podocyte senescence. Material and methodsLiquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to characterize components of SWT. Male Sprague-Dawley rats were given 10% fructose drinking water for 16 weeks. SWT (810 and 1620 mg/kg) was administered orally for the last 8 weeks. The assays of senescence-associated beta-galactosidase (SA-β-gal) staining, immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot as well as enzyme linked immunosorbent assay were performed to evaluate rat glomerular podocyte senescence. The mRNA and protein levels of nucleoporin 155 (Nup155) and inositol requiring mutant 80 (INO80) in rat glomeruli were detected by qRT-PCR, Western blot and immunofluorescence. Foot processes and nuclear pore complexes (NPCs) of rat glomerular podocytes were visualized by transmission electron microscopy. ResultsOne hundred and fifty-nine components were preliminarily identified in SWT. The results of animal experiments showed that SWT decreased the activity of SA-β-gal, protein levels of p16, p21, p53 and phosphorylated histone H2AX (γ-H2AX), and mRNA levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) in glomeruli of high fructose-fed rats. As expected, SWT increased renal cortex erythropoietin mRNA expression and serum erythropoietin concentration in this animal model. SWT reduced urine albumin-to-creatinine ratio and serum levels of uric acid, creatinine and blood urea nitrogen, and recovered glomerular structure injury in high fructose-fed rats. It up-regulated mRNA and protein levels of Nup155 and the number of podocyte NPCs, and subsequently reinforced mRNA nuclear export and protein expression of INO80 in rat glomeruli under high fructose stimulation. ConclusionsSWT ameliorates glomerular podocyte senescence in high fructose-fed rats possibly by increasing Nup155 to promote INO80 mRNA nuclear export.

The KCa3.1 channel blocker TRAM-34 and minocycline prevent fructose-induced hypertension in rats.

High fructose consumption increases blood pressure through microglia-related neuroinflammation in rats. Since intermediate-conductance calcium-activated potassium channels (KCa3.1) potentiates microglial reactivity, we examined whether the pretreatment with the KCa3.1 channel blocker TRAM-34 or minocycline prevents hypertension development in fructose-fed rats. The study involved male Wistar rats that were given either a high fructose (10% in drinking water) or a tap water for 21 days. Fructose groups also received minocycline or TRAM-34 systemically for 21 days. We measured systolic and diastolic blood pressure (SBP and DBP), heart rate (HR) periodically with tail-cuff; proinflammatory cytokines and insulin levels in plasma via ELISA, and neuroinflammatory markers in the nucleus tractus solitarii (NTS) by qPCR at the end of 21 days. We also examined endothelium-dependent hyperpolarization (EDH)-type vasorelaxations in isolated mesenteric arteries of the rats ex vivo. SBP, DBP, and HR increased in the fructose group. Both minocycline and TRAM-34 significantly prevented these increases. Fructose intake also increased plasma IL-6, IL-1β, TNF-α, and insulin levels, whereas pretreatment with TRAM-34 prevented these increases as well. Iba-1, but not CD86 levels were significantly higher in the NTS samples of fructose-fed hypertensive rats which implied microglial proliferation. EDH-type vasorelaxations mediated by endothelial KCa3.1 attenuated in the fructose group; however, TRAM-34 did not cause further deterioration in the relaxations. TRAM-34 is as effective as minocycline in preventing fructose-induced hypertension without interfering with the EDH-type vasodilation. Furthermore, TRAM-34 relieves high fructose-associated systemic inflammation.

Anti-diabetic activity of aqueous extract of Trichilia prieureana A. Juss leaves in fructose-fed streptozotocin-induced diabetic male Wistar rats

Background and aimEthanolic extract of Trichilia prieureana leaves have been reported to exhibit anti-hyperglycemic activities without detailed information on the anti-diabetic activities. This study investigated the anti-diabetic activity of aqueous extract of T. prieureana leaves (AETPL) in type 2 diabetic (T2DM) male rats. Experimental procedureT2DM rats (induced with 10 % fructose solution ad libitum for 2 weeks and streptozotocin [STZ]; 40 mg/kg body weight {BW}) in groups B, C, D, E, and F were also administered distilled water (DW), metformin (100 mg/kg BW), 11.2, 22.3, and 44.6 mg/kg BW of AETPL, respectively, whilst non-diabetic rats in Group A received DW only (Sham Control, SC) for 14 days. The T2DM-related parameters were then evaluated. ResultsThe fructose-fed streptozotocin-(FSTZ) treatment related significant (p < 0.05) increases in FBS, HbA1c, fructosamine, HOMA-IR, G6P, GP, TC, TG, LDL-C, urea, bilirubin, hepatic and pancreatic MDA levels; decreases in BW, serum insulin, creatinine, albumin, HOMA-β, glycogen, G6PD, HK, HDL-C, hepatic and pancreatic SOD, GPX, RG, catalase, Hb, PCV, MCH, MCHC, MCV, RBC, WBC, differentials and the destruction of the pancreatic β-cells, hepatocyte degeneration, and central hepatic vein congestion were reversed by AETPL, to values that compared well with SC in most cases. In the IpGGT model, the intraperitoneally administered AETPL reduced the blood glucose and elevated the plasma insulin levels. The AETPL at 44.6 mg/kg BW exhibited the most pronounced effects. ConclusionAETPL (44.6 mg/kg BW) restored T2DM-glycemic control and associated biochemical changes via up-regulation of insulin, carbohydrate metabolizing enzymes and restoration of pancreatic and hepatic histoarchitecture.

Investigation of the relationship between inflammation and microbiota in the intestinal tissue of female and male rats fed with fructose: Modulatory role of metformin.

It has been reported that High-Fructose (HF) consumption, considered one of the etiological factors of Metabolic Syndrome (MetS), causes changes in the gut microbiota and metabolic disorders. There is limited knowledge on the effects of metformin in HF-induced intestinal irregularities in male and female rats with MetS. In this study, we investigated the sex-dependent effects of metformin treatment on the gut microbiota, intestinal Tight Junction (TJ) proteins, and inflammation parameters in HF-induced MetS. Fructose was given to the male and female rats as a 20% solution in drinking water for 15weeks. Metformin (200mg/kg) was administered by gastric tube once a day during the final seven weeks. Biochemical, histopathological, immunohistochemical, and bioinformatics analyses were performed. Differences were considered statistically significant at p < 0.05. The metformin treatment in fructose-fed rats promoted glucose, insulin, Homeostasis Model Assessment of Insulin Resistance Index (HOMA-IR), and Triglyceride (TG) values in both sexes. The inflammation score was significantly decreased with metformin treatment in fructose-fed male and female rats (p < 0.05). Moreover, metformin treatment significantly decreased Interleukin-1 Beta (IL-1β) and Tumor Necrosis Factor-Alpha (TNF-α) in ileum tissue from fructose-fed males (p < 0.05). Intestinal immunoreactivity of Occludin and Claudin-1 was increased with metformin treatment in fructose-fed female rats. HF and metformin treatment changed the gut microbial composition. Firmicutes/Bacteroidetes (F/B) ratio increased with HF in females. In the disease group, Bifidobacterium pseudolongum; in the treatment group, Lactobacillus helveticus and Lactobacillus reuteri are the prominent species in both sexes. When the male and female groups were compared, Akkermansia muciniphila was prominent in the male treatment group. In conclusion, metformin treatment promoted biochemical parameters in both sexes of fructose-fed rats. Metformin showed a sex-dependent effect on inflammation parameters, permeability factors, and gut microbiota. Metformin has partly modulatory effects on fructose-induced intestinal changes.

Approaches to nutritional research using organoids; fructose treatment induces epigenetic changes in liver organoids

Nutritional researches have successfully used animal models to gain new insights into nutrient action. However, comprehensive descriptions of their molecular mechanisms of action remain elusive as appropriate in vitro evaluation systems are lacking. Organoid models can mimic physiological structures and reproduce in vivo functions, making them increasingly utilized in biomedical research for a better understand physiological and pathological phenomena. Therefore, organoid modeling can be a powerful approach for to understand the molecular mechanisms of nutrient action. The present study aims to demonstrate the utility of organoids in nutritional research by further investigating the molecular mechanisms responsible for the negative effects of fructose intake using liver organoids. Here, we treated liver organoids with fructose and analyzed their gene expression profiles and DNA methylation levels. Microarray analysis demonstrated that fructose-treated organoids exhibited increased selenoprotein p (Sepp1) gene expression, whereas pyrosequencing assays revealed reduced DNA methylation levels in the Sepp1 region. These results were consistent with observations using hepatic tissues from fructose-fed rats. Conversely, no differences in Sepp1 mRNA and DNA methylation levels were observed in two-dimensional cells. These results suggest that organoids serve as an ideal in vitro model to recapitulate in vivo tissue responses and help to validate the molecular mechanisms of nutrient action compared to conventional cellular models.

Impact of Renin Angiotensin System Inhibition on Renal Function in Fructose-induced Salt Sensitive Blood Pressure

Combined dietary intake of fructose with high salt at levels comparable to that in the upper quintile of western population increases blood pressure, decreases glomerular filtration rate, and results in albuminuria and insulin resistance. We tested the hypothesis that chronic treatment with either an angiotensin converting enzyme inhibitor (enalapril) or angiotensin receptor blocker (losartan) will preserve glomerular filtration rate (GFR) and reduce albuminuria. Sprague Dawley rats of both sexes were instrumented with telemetry. After a baseline period on glucose+0.4% NaCl, rats were assigned to the following groups: 20% glucose+0.4%NaCl treated with vehicle (GNS+V) or 20% fructose+4% NaCl and treated with either vehicle (FHS+V), losartan 0.42 mg/kg/hr by osmotic minipump (FHS+L) or enalapril 0.21 mg/kg/hr (FHS+E). The doses of losartan and enalapril were chosen to achieve MAP similar to the control GNS+V group. Body weights did not differ among the groups upon entry into the protocol and increased similarly among the groups. Non-fasting blood glucose was elevated in all groups in both male and female rats. Mean arterial pressure (MAP) was 108±2 mmHg in GNS+V but was elevated in the FHS+V male rats, 118±2 mmHg ( P&lt;0.01). FHS+L and FHS+E displayed MAP similar GNS+V rats: 104±2 and 106±2 mmHg, respectively. GFR assessed by transdermal FITC-sinistrin elimination was similar across all groups: 0.85±0.04 (GNS+V), 0.86±0.08 (FHS+V), 0.94±0.10 (FHS+L), 1.13±0.12 ml/min/100 g bw (FHS+E). Female rats did not display elevated MAP: 108±1 mmHg (FHS+V) vs 105±2 mmHg (GNS+V). Losartan and enalapril did not change MAP, but GFR was higher in female FHS+L rats, 1.14± 0.05, vs GNS+V 0.75±0.06 ( P &lt; 0.05). Thus, male but not female fructose-fed rats on high salt diet display significantly higher blood pressure. Short-term fructose high salt feeding did not change GFR in either male or female rats. RAS inhibition did not impact GFR in male rats, but losartan increased GFR in female rats on high fructose plus high salt diet compared with glucose-fed female rats on normal salt diet. R01 HL163844. This is the full abstract presented at the American Physiology Summit 2024 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.

YÜKSEK FRUKTOZLA BESLENEN SIÇANLARDA QUERCETİN’İN PERİRENAL YAĞ DOKUSUNDAKİ ADİPONEKTİN VE REZİSTİN DÜZEYLERİNE ETKİSİ

Obesity is defined as the accumulation of adipose tissue to excess and to an extent that impairs both physical and psychosocial health and well-being. The increase in adipose tissue observed in obesity causes proinflammatory and anti-inflammatory cytokine imbalance. Accumulating evidence on quercetin, one of the antioxidants frequently used in obesity treatment, suggests that quercetin has significant anti-obesity and lipid-lowering effects simultaneously. We hypothesized that quercetin supplementation could improve obesity parameters and restore adipokine balance in obese mice. Sprague Dawley rats, 8-10 weeks of age, were divided into 4 groups, including a control group (C), high fructose (HF) group, quercetine (Q) group, and high fructose+quercetin (HF+Q) group. Fructose was administered to HF groups as a 20% solution in drinking water for 6 weeks. The rats in the Q groups were given 50 mg quercetin per kg BW by gavage for the next 4 weeks. The body weight, lee index, TG, HDL, fasting insülin, fasting glucose, and HOMA-IR were determined in rats. ADP and resistin levels were determined by ELISA assay from perirenal adipose tissue homogenates. We showed that quercetin acts to improve TG, fasting glucose and insulin resistance in high fructose-fed rats. In this study, we found no effect of quercetin on perirenal adipose tissue ADP and resistin levels. These results showed that high fructose could induce obesity in rats, while quercetin could favorably affect these parameters.

Synaptic mechanisms underlying the elevated sympathetic outflow in fructose-induced hypertension.

Metabolic syndrome is associated with cardiovascular dysfunction, including elevated sympathetic outflow. However, the underlying brain mechanisms are unclear. The nucleus tractus solitarius (NTS) critically regulates autonomic reflexes related to cardiovascular function and contains neurons projecting to the caudal ventrolateral medulla (CVLM). Nitric oxide (NO) is a diffusible free-radical messenger in the vascular, immune, and nervous systems. In this study, we determine if NO in the NTS is involved in the synaptic plasticity underlying the elevated sympathetic outflow in fructose-induced hypertension. We retrogradely labeled CVLM-projecting NTS neurons through the injection of FluoSpheres into the CVLM in a fructose-fed rat model to determine the cellular mechanism involved in increased sympathetic outflow. Fructose feeding increased the blood pressure and glucose levels, which represent metabolic syndrome. We found that fructose feeding reduces the NO precursor L-arginine-induced increase in the firing activity of CVLM-projecting NTS neurons. Furthermore, fructose feeding reduces the L-arginine-induced increase in presynaptic spontaneous glutamatergic synaptic inputs to NTS neurons, while NO donor DEA/NO produces an increase in glutamatergic synaptic inputs in fructose-fed rats similar to that in vehicle-treated rats. In addition, fructose feeding reduces the NO-induced depressor response and sympathoinhibition. These data suggested that fructose feeding reduced NO production and, thus, the subsequent NO-induced glutamate releases in the NTS and depressor response. The findings of this study provide new insights into the central mechanisms involved in the neural control of cardiovascular and autonomic functions in the NTS in metabolic syndrome.

Manifestations of Liver Impairment and the Effects of MH-76, a Non-Quinazoline α1-Adrenoceptor Antagonist, and Prazosin on Liver Tissue in Fructose-Induced Metabolic Syndrome.

Excessive fructose consumption may lead to metabolic syndrome, metabolic dysfunction-associated fatty liver disease (MAFLD) and hypertension. α1-adrenoceptors antagonists are antihypertensive agents that exert mild beneficial effects on the metabolic profile in hypertensive patients. However, they are no longer used as a first-line therapy for hypertension based on Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) outcomes. Later studies have shown that quinazoline-based α1-adrenolytics (prazosin, doxazosin) induce apoptosis; however, this effect was independent of α1-adrenoceptor blockade and was associated with the presence of quinazoline moiety. Recent studies showed that α1-adrenoceptors antagonists may reduce mortality in COVID-19 patients due to anti-inflammatory properties. MH-76 (1-[3-(2,6-dimethylphenoxy)propyl]-4-(2-methoxyphenyl)piperazine hydrochloride)) is a non-quinazoline α1-adrenoceptor antagonist which, in fructose-fed rats, exerted anti-inflammatory, antihypertensive properties and reduced insulin resistance and visceral adiposity. In this study, we aimed to evaluate the effect of fructose consumption and treatment with α1-adrenoceptor antagonists of different classes (MH-76 and prazosin) on liver tissue of fructose-fed rats. Livers were collected from four groups (Control, Fructose, Fructose + MH-76 and Fructose + Prazosin) and subjected to biochemical and histopathological studies. Both α1-adrenolytics reduced macrovesicular steatosis and triglycerides content of liver tissue and improved its antioxidant capacity. Treatment with MH-76, contrary to prazosin, reduced leucocytes infiltration as well as decreased elevated IL-6 and leptin concentrations. Moreover, the MH-76 hepatotoxicity in hepatoma HepG2 cells was less than that of prazosin. The use of α1-adrenolytics with anti-inflammatory properties may be an interesting option for treatment of hypertension with metabolic complications.

Spirulina platensis improves insulin sensitivity and reduces hyperglycemia-mediated oxidative stress in fructose-fed rats

Oxidative stress, hyperglycemia and insulin resistance are hallmarks of diabetes mellitus. The present study aimed to assess the antidiabetic activity of a local strain of Spirulina platensis produced at Pahou (Benin), known as “Spiruline Dou Bogan” (SPD), in fructose-fed rats. Glucose metabolism impairment was induced by feeding 8g/kg, body weight (bw), fructose solution orally to Sprague Dawley rats (n = 8) for 56 days, treated with SPD (18.75; 37.5 and 75 mg/kg, bw), and analyzed for plasma blood glucose, serum biochemistry and the markers of oxidative stress (Ferric Reducing Antioxidant Power Assay (FRAP), Malondialdehyde (MDA), Reduced glutathione (GSH), DPPH radical scavenging assay. SPD concentrations, given orally for 42 days, significantly reversed the elevations in plasma blood glucose, MDA, and the reduction in kidneys glutathione activity. Oral administration of 18.75, 37.5, and 75 mg/kg doses of SPD also lowered serum Aspartate Aminotransferase (ASAT), Alanine Aminotransferase (ALAT), Triglycerides and Creatinine levels. SPD 75 mg/kg treatment in particular has significantly decreased serum Triglycerides level and increased HDL-Cholesterol levels, reversing the atherogenic potential of 56 days fructose administration. The consumption of S. platensis produced locally in Benin as a food supplement, easily accessible for low-income populations, may be helpful in the prevention and management of type 2 diabetes.&#x0D; Keywords: Oxidative stress; Spirulina platensis; hyperglycemia; insulin resistance, fructose diet

The effect of exenatide (a GLP-1 analogue) and sitagliptin (a DPP-4 inhibitor) on asymmetric dimethylarginine (ADMA) metabolism and selected biomarkers of cardiac fibrosis in rats with fructose-induced metabolic syndrome

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthesis, is a risk factor for endothelial dysfunction, a common pathophysiological denominator for both atherogenesis and cardiac fibrosis.We aimed to investigate whether the cardioprotective and antifibrotic effects of incretin drugs, exenatide and sitagliptin, may be associated with their ability to affect circulating and cardiac ADMA metabolism.Normal and fructose-fed rats were treated with sitagliptin (5.0/10 mg/kg) or exenatide (5/10 µg/kg) for 4 weeks. The following methods were used: LC-MS/MS, ELISA, Real-Time-PCR, colorimetry, IHC and H&E staining, PCA and OPLS-DA projections.Eight-week fructose feeding resulted in an increase in plasma ADMA and a decrease in NO concentration. Exenatide administration into fructose-fed rats reduced the plasma ADMA level and increased NO level. In the heart of these animals exenatide administration increased NO and PRMT1 level, reduced TGF-ß1, α-SMA levels and COL1A1 expression. In the exenatide treated rats renal DDAH activity positively correlated with plasma NO level and negatively with plasma ADMA level and cardiac α-SMA concentration. Sitagliptin treatment of fructose-fed rats increased plasma NO concentration, reduced circulating SDMA level, increased renal DDAH activity and reduced myocardial DDAH activity. Both drugs attenuated the myocardial immunoexpression of Smad2/3/P and perivascular fibrosis.In the metabolic syndrome condition both sitagliptin and exenatide positively modulated cardiac fibrotic remodeling and circulating level of endogenous NOS inhibitors but had no effects on ADMA levels in the myocardium.

Cemtirestat, an aldose reductase inhibitor and antioxidant compound, induces ocular defense against oxidative and inflammatory stress in rat models for glycotoxicity.

Fructose, endogenously produced as a consequence of activation of the polyol pathway under hyperglycemic conditions, contribute to formation of advanced glycoxidation end products (AGEs) and carbonyl stress. Oxidative stressis increased in diabetes (DM) due to AGEs formation and the utilization of NADPH by aldo-keto reductase, AKR1B1(AR), the first enzyme in polyol pathway. Since inhibition of AR is an attractive approach for the management of diabetic eye diseases, we aimed to compare the effects of a novel AR inhibitor (ARI)/antioxidant (AO) compound cemtirestat on eye tissues with the effects of ARI drug epalrestat and AOagent stobadine in rat model for glycotoxicity. One group of rats was fed high fructose (10% drinking water; 14 weeks), while type-2 DM was induced in the other group of rats with fructose plus streptozotocin (40 mg/kg-bw/day). Diabetic (D) and nondiabetic fructose-fed rats (F) were either untreated or treated with two different doses of cemtirestat (2.5 and 7.5 mg/kg-bw/day), epalrestat (25 and 50 mg/kg-bw/day),or stobadine (25 and 50 mg/kg-bw/day) for 14 weeks. Cemtirestat, epalrestat, and stobadine elaviate the increase in TNF-α, IL-1β, NF-ƙB, and caspase-3 in retina, lens, cornea, and sclera of F and D rats. Both glycotoxicity models resulted in a decrease in GSH to GSSG ratio and a change in glutathione S-transferase activity in eye tissues, but these alterations were improved especially with cemtirestat and stobadine. Lens D-sorbitol of D rats increased more than that of F rats, this increase was only attenuated by cemtirestat and epalrestat. Epalrestat was more effective than cemtirestat and stobadine in inhibiting the increase of vascular endothelial growth factor (VEGF)in the retina of F and D rats. Cemtirestat and stobadine but not epalrestat decreased high level of Nε-(carboxymethyl)lysine in the lens and retina of F and D rats. Cemtirestat is a potential therapeutic in protecting the rat eye against glycotoxicity insults.

The Impact of Resveratrol-Enriched Bread on Cardiac Remodeling in a Preclinical Model of Diabetes.

The World Health Organization aims to stop the rise of diabetes by 2025, and diet is one of the most efficient non-pharmacological strategies used to prevent it. Resveratrol (RSV) is a natural compound with anti-diabetic properties, and incorporating it into bread is a suitable way to make it more accessible to consumers as it can be included as part of their daily diet. This study aimed to evaluate the effect of RSV-enriched bread in preventing early type 2 diabetes cardiomyopathy in vivo. Male Sprague Dawley rats (3 weeks old) were divided into four groups: controls with plain bread (CB) and RSV bread (CBR), and diabetics with plain bread (DB) and RSV bread (DBR). Type 2 diabetes was induced by adding fructose to the drinking water for two weeks followed by an injection of streptozotocin (STZ) (40 mg/kg). Then, plain bread and RSV bread (10 mg RSV/kg body weight) were included in the rats' diet for four weeks. Cardiac function, anthropometric, and systemic biochemical parameters were monitored, as well as the histology of the heart and molecular markers of regeneration, metabolism, and oxidative stress. Data showed that an RSV bread diet decreased the polydipsia and body weight loss observed in the early stages of the disease. At the cardiac level, an RSV bread diet diminished fibrosis but did not counteract the dysfunction and metabolic changes seen in fructose-fed STZ-injected rats.

Fructose-induced salt-sensitive blood pressure differentially affects sympathetically mediated aortic stiffness in male and female Sprague-Dawley rats.

Hypertension is the leading risk factor for major adverse cardiovascular events (MACE). Aortic stiffness and sympathoexcitation are robust predictors of MACE. Combined high fructose and sodium intake increases arterial pressure, aortic stiffness, renin, and sympathetic nerve activity in male rats. We hypothesized that activation of the renin angiotensin system (RAS) and/or the sympathetic system mediates aortic stiffness in rats with fructose-induced salt-sensitive blood pressure. Male and female Sprague-Dawley rats ingested 20% fructose or 20% glucose in drinking water with 0.4% NaCl chow for 1 week. Then, fructose-fed rats were switched to 4% NaCl chow (Fru + HS); glucose-fed rats remained on 0.4% NaCl chow (Glu + NS, controls for caloric intake). After 2 weeks, mean arterial pressure (MAP) and aortic pulsed wave velocity (PWV) were evaluated at baseline or after acute intravenous vehicle, clonidine, enalapril, losartan, or hydrochlorothiazide. Baseline global longitudinal strain (GLS) was also assessed. MAP and PWV were greater in male Fru + HS versus Glu + NS male rats (p < 0.05 and p < 0.001, respectively). PWV was similar between the female groups. Despite similarly reduced MAP after clonidine, PWV decreased in Fru + HS versus Glu + NS male rats (p < 0.01). Clonidine induced similar decreases in MAP and PWV in females on either diet. GLS was lower in Fru + HS versus Glu + NS male rats and either of the female groups. Thus, acute sympathoinhibition improved aortic compliance in male rats with fructose salt-sensitive blood pressure. Female rats retained aortic compliance regardless of diet. Acute RAS inhibition exerted no significant effects. Male rats on fructose high salt diet displayed an early deficit in myocardial function. Taken together, these findings suggest that adult female rats are protected from the impact of fructose and high salt diet on blood pressure, aortic stiffness, and early left ventricular dysfunction compared with male rats.

Green-synthesized nanoparticles of the polyherbal extract attenuate the necrosis of pancreatic β-cell in a streptozotocin-induced diabetic model

Plant-based nanoformulation is one of the novel approaches for therapeutic benefits. This research synthesized a silver nanoparticle from the polyherbal combination of four plants/seeds (Momordica charantia, Trigonella foenum-graecum, Nigella sativa, and Ocimum sanctum) and investigated its antidiabetic effects in streptozotocin-induced Wistar albino rat model. The polyherbal extract (PH) was extracted by the Soxhlet-solvent extraction method and the resulting crude extract was undergone for silver nanoparticle synthesis. The PH extract was subjected to a four-week intervention in fructose-fed streptozotocin-induced Wistar Albino rats’ models and in vitro antioxidative tests. Experimental animals (age: 6–7 weeks, male, body weight: 200–220 g), were divided into five groups including normal control (NC), reference control (RC), diabetic control (DC), and treatment groups PH200, PH100, and PHAgNP20. After three weeks of intervention, body weight, weekly blood glucose level, oral glucose tolerance test, AST, ALT, alkaline phosphatase, total cholesterol, triglycerides, uric acid, urea, and creatinine level of PH200 were found to be significantly (P < 0.05) improved compared to the diabetic control. The same dose demonstrated better regeneration of damaged pancreatic and kidney tissues. In vitro antioxidant assay manifested promising IC50 values of 86.17 μg/mL for DPPH, 711.04 μg/mL for superoxide free radical, and 0.48 mg/mL for Iron chelating activity of the polyherbal extract. GC-MS analysis impacted the major volatile compounds of the PH. The data demonstrate that the PH and its nanoparticles could be a novel source of antidiabetic therapeutics through an advanced dose-response study in the type 2 diabetic model.

ChREBP/ ChREBP-beta expression mediates the paradoxical effect of fructose on body weight of fructose-fed rats by brown adipose tissue activation

Introduction: Western diet fructose content is a neglected nutrition component, with significant devastating metabolic effects like metabolic syndrome (MeS) and obesity. The data suggest that Food-induced thermogenesis is a contributing factor for regulating body weight. Carbohydrate Responsive Element Binding Protein-beta (ChREBPβ) is recognized now as the regulator of fructose metabolism. Brown adipose tissue (AT) which plays essential role as a thermoregulatory organ, is recognized now also as an endocrine tissue that participates in glucose and lipids metabolism. ChREBP expression is associated with activating of BAT and improve metabolic status. On the other hand, increased ChREBPβ seems to have a deleterious metabolic effect on brown AT. Methods: Sprague-Dawley male rats, 8 weeks old were fed High Fructose Diet (HFRD) or match regular chow for 6 weeks (n=8). Body weight (BW) and precise food intake were measured weekly. Brown (peri-aortic and interscapular, PA and IS respectively) and white (mesenteric) AT were collected for further molecular studies. Results: HFrD fed rats gain significantly less weight than the control group (from 236±2 to 397±8 vs. 233±2 to 430±9 gr. P&lt;0.05) despite eating an equal food amount (28±1vs.29±1.5 g/rat/week). The expression of uncoupling 1 (UCP1) mRNA, a BAT activation marker, was significantly higher in BAT than in WAT. Fructose consumption increased UCP1 BAT expression compared to regular chow. However, the expression of ChREBP and ChREBPβ in BAT was significantly lower in HFrD fed rats. Conclusions: In the HFrD rat model of MeS, fructose consumption leads to lesser weight gain for the same caloric intake. This BW difference is accompanied by the activation of BAT in the HFrD group. This paradoxical effect may be regulated by decreased ChREBP/ChREBPβ expression in response to fructose. No disclosure 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 quercetin on hepatic fibroblast growth factor-21 (FGF-21) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) levels in rats fed with high fructose

Available studies show that quercetin reduces Metabolic Syndrome (MetS) and its complications, increases insulin sensitivity and improves glucose levels. It has been reported that the increase in hepatic gene expressions of fibroblast growth factor-21 (FGF-21), an important metabolic regulator of insulin sensitivity, glucose and energy homeostasis, and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α), which plays a central role in the regulation of cellular energy metabolism, eliminate the negative effects of fructose in fructose-fed rats. The main purpose of our study is to examine the effects of quercetin on hepatic FGF-21 and PGC-1α expressions and levels, as well as its protective and therapeutic role on MetS components in rats fed with fructose. In our study, 24 Sprague Dawley male rats were divided into 4 groups: control, fructose, quercetin, fructose+quercetin (n = 6). During the 10-week experiment, quercetin was administered at a daily dose of 15mg/kg body weight and fructose at a rate of 20%. Blood pressure and weights of all groups were measured and recorded. At the end of week 10, blood and liver tissue samples were taken. Serum insulin, glucose and triglyceride, total, HDL and VLDL cholesterol levels were determined from the samples. Insulin resistance was calculated using the HOMA-IR formula. Hepatic PGC-1α and FGF-21 protein levels and their mRNA expressions were determined. Criteria for metabolic syndrome were successfully established with fructose. It was observed that the administration of quercetin alone and in combination with fructose exerted positive effects and improved MetS criteria. It was determined that the administration of quercetin increased hepatic FGF-21 and PGC-1α protein levels and Messenger RNA (mRNA) expressions of them, which were decreased by fructose application. The results of our study showed that 10-week administration of quercetin at 15mg/kg exerted beneficial effects on lipid and carbohydrate metabolism in the fructose-mediated MetS model; therefore, quercetin may have great potential in the prevention and treatment of metabolic disorders.

Pharmacological screening of glibenclamide solid dispersion in fructose-fed diabetic rats

Abstract Objectives In this study, our main objective was to estimate the therapeutic effectiveness of the formulated solid dispersion of glibenclamide (GSD) with improved dissolution profiles in comparison with pure glibenclamide (GLB) by means of a fructose-fed diabetic rat model. Methods To evaluate the pharmacological effectiveness of the formulated GSD, a fructose-fed diabetic rat model evolved and the obtained consequences were compared with the conventional GLB treatment. Key findings GSD exhibited improved glucose and lipid-lowering efficacy of GSD in contrast to pure GLB after 15 days of treatment. Low dose (0.5 mg/kg) and high dose (5 mg/kg) of GSD showed significant lowering of blood glucose which is 6 ± 0.2 mmol/L and 5.6 ± 0.3 mmol/L respectively after 15 days of treatment is much better than that of pure GLB (6.2 ± 0.4 mmol/L). Furthermore, low dose of GSD presented approximately comparable beneficiary effects in regard to triglycerides (72.00 ± 7.23 mg/dL), total cholesterol (110.33 ± 5.78 mg/dL), low-density lipoprotein (67.60 ± 5.21 mg/dL) and high-density lipoprotein (28.33 ± 1.53 mg/dL) as pure GLB after 15 days. Additionally, histological studies as well confirmed no fatty infiltration from the liver by GSD as compared with GLB which was consistent with the biochemical parameters. Conclusions For treating diabetes and hyperlipidaemia, the formulated GSD might be a potential substitute for traditional GLB.

A Fructose-Rich Diet Decreases Insulin-Stimulated Glucose Incorporation into Lipids but Not Glucose Transport in Adipocytes of Normal and Diabetic Rats

To study the cellular mechanisms underlying fructose-induced insulin resistance in rats, the effects of fructose feeding on insulin-stimulated glucose transport, oxidation and incorporation into lipids in epididymal adipocytes were evaluated in 27 normal and 27 noninsulin-dependent diabetic male Sprague-Dawley rats. Diabetes was induced by streptozotocin injection 2 d after birth. At 5 wk of age, both normal and diabetic rats were fed a diet containing 62% carbohydrate as fructose, dextrose or cornstarch. Fructose feeding for 6 wk induced glucose intolerance in normal rats (P < 0.05) and aggravated that of diabetic rats (P < 0.05). Plasma triacylglycerol concentration was higher in fructose-fed than in starch-fed or dextrose-fed rats (P < 0.05). Adipocytes of fructose-fed rats had significantly lower maximum insulin-stimulated glucose incorporation into total lipids than those of rats fed starch, and tended (P = 0.22) to have lower production of CO2 from glucose than adipocytes of the other dietary groups. Glucose transport in adipocytes of dextrose-, starch- and fructose-fed rats did not differ. We conclude that in both normal and diabetic rats, a chronic fructose-rich diet induced hypertriacylglycerolemia, glucose intolerance and insulin resistance of adipocytes.