Copper nanoparticles modify the blood plasma antioxidant status and modulate the vascular mechanisms with nitric oxide and prostanoids involved in Wistar rats

The Effect of an Elevated Dietary Copper Level on the Vascular Contractility and Oxidative Stress in Middle-Aged Rats

Copper (Cu), being an essential mineral, plays a crucial role in maintaining physiological homeostasis across multiple bodily systems, notably the cardiovascular system. However, an increased Cu level in the body may cause blood vessel dysfunction and oxidative stress, which is unfavorable for the cardiovascular system. Middle-aged (7-8 months old) male Wistar rats (n/group = 12) received a diet supplemented with 6.45 mg Cu/kg (100% of the recommended daily dietary quantity of copper) for 8 weeks (Group A). The experimental group received 12.9 mg Cu/kg of diet (200%-Group B). An ex vivo study revealed that supplementation with 200% Cu decreased the contraction of isolated aortic rings to noradrenaline (0.7-fold) through FP receptor modulation. Vasodilation to sodium nitroprusside (1.10-fold) and acetylcholine (1.13-fold) was potentiated due to the increased net effect of prostacyclin derived from cyclooxygenase-1. Nitric oxide (NO, 2.08-fold), superoxide anion (O2•-, 1.5-fold), and hydrogen peroxide (H2O2, 2.33-fold) measured in the aortic rings increased. Blood serum antioxidant status (TAS, 1.6-fold), Cu (1.2-fold), Zn (1.1-fold), and the Cu/Zn ratio (1.4-fold) increased. An increase in Cu (1.12-fold) and the Cu/Zn ratio (1.09-fold) was also seen in the rats' livers. Meanwhile, cyclooxygenase-1 (0.7-fold), cyclooxygenase-2 (0.4-fold) and glyceraldehyde 3-phosphate dehydrogenase (0.5-fold) decreased. Moreover, a negative correlation between Cu and Zn was found (r = -0.80) in rat serum. Supplementation with 200% Cu did not modify the isolated heart functioning. No significant difference was found in the body weight, fat/lean body ratio, and organ weight for either the heart or liver, spleen, kidney, and brain. Neither Fe nor Se, the Cu/Se ratio, the Se/Zn ratio (in serum and liver), heme oxygenase-1 (HO-1), endothelial nitric oxide synthase (eNOS), or intercellular adhesion molecule-1 (iCAM-1) (in serum) were modified. Supplementation with 200% of Cu potentiated pro-oxidant status and modified vascular contractility in middle-aged rats.

Nano-copper Enhances Gene Regulation of Non-specific Immunity and Antioxidative Status of Fish Reared Under Multiple Stresses

Arsenic pollution, water temperature, and pH are the major concern for aquaculture. Moreover, the aim of the present investigation was to delineate the role of nano-copper (Cu-NPs) in the mitigation of arsenic toxicity, high temperature (34 °C) and low pH (6.5) stress on Pangasianodon hypophthalmus. Four isonitrogenous and isocaloric experimental diets of Cu-NPs at 0, 1.0, 1.5 and 2.0 mg kg-1 were formulated and prepared. Arsenic pollution, low pH and high temperature stress significantly reduced the anti-oxidative status (super oxide dismutase, catalase, glutathione peroxidase and glutathione-s-transferase), lipid peroxidation, total anti-oxidative capacity and lipid profiling (cholesterol, total lipid, phospholipid, very low-density lipoprotein and triglyceride). Further, the supplementation of Cu-NPs at 1.5 and 1.0 mg kg-1 diets noticeably improve the anti-oxidant status and capacity. The stressors groups (As + pH + T, As + T and As) significantly reduced fish immunity viz. albumin, globulin, total protein, albumin globulin ratio (A:G ratio), myeloperoxidase, respiratory burst activities, tumor necrosis factor, total immunoglobulin, and interleukin. Whereas supplementation of Cu-NPs at 1.5 and 1.0 mg kg-1 diets improved the immunity of the fish reared under multiple stresses (As + pH + T). Tail DNA %, DNA damage-inducible protein (DDIP) and inducible nitric oxide (iNOS) synthase gene expression were significantly enhanced with exposure to arsenic, low pH and high temperature but supplementation of Cu-NPs protects the tissues against DNA damage and improved the gene expression of iNOS and DDIP. Cu-NPs at 1.5 and 1.0 mg kg-1 diets significantly enhanced the body weight gain %, protein efficiency ratio, specific growth rate, daily growth index, relative feed intake and reduced the feed conversion ratio. Whereas, the growth-related gene expression such as myostatin (MYST), somatostatin (SMT) was downregulated by Cu supplementation and upregulated the gene expression of growth hormone regulator 1 and β (GHR1 and GHR β) and growth hormone (GH) gene in fish. Dietary Cu-NPs supplementation protects the fish against bacterial infection and enhances arsenic detoxification in different tissues. The present investigation revealed that supplementation of Cu-NPs at 1.5 and 1.0 mg kg-1 diet has the potential to mitigate multiple stress (As + pH + T) in fish.

The Interaction of Dietary Pectin, Inulin, and Psyllium with Copper Nanoparticle Induced Changes to the Cardiovascular System

We aimed to analyze how supplementation with a standard (recommended, 6.5 mg/kg) or enhanced (two-times higher, 13 mg/kg) dose of copper (Cu), in the form of nanoparticles (NPs) along with dietary intervention via the implementation of diverse types of fiber, affects the cardiovascular system in rats. Nine-week-old male Wistar Han rats (n/group = 10) received, for an additional 6 weeks, a controlled diet with cellulose as dietary fiber and ionic Cu (in the form of carbonate salt). The experimental groups received cellulose, pectin, inulin, and psyllium as dietary fiber, together with CuNPs (6.5 or 13 mg/kg diet). After the experimental feeding, samples of blood, hearts, and thoracic arteries were collected for further analysis. Compared to pectin, and under a standard dose of CuNPs, inulin and psyllium beneficially increased the antioxidant capacity of lipid- and water-soluble compounds in the blood, and decreased heart malondialdehyde. Moreover, pectin decreased heart catalase (CAT) and cyclooxygenase (COX)-2 in the aortic rings compared to inulin and psyllium under standard and enhanced doses of copper. When the dose of CuNPs was enhanced, inulin and psyllium potentiated vasodilation to acetylcholine by up-regulation of COX-2-derived vasodilator prostanoids compared to both cellulose and pectin, and this was modulated with selective inducible nitric oxide synthase (iNOS) inhibitor for psyllium only. Moreover, inulin decreased heart CAT compared to psyllium. Our results suggest that supplementation with dietary fiber may protect the vascular system against potentially harmful metal NPs by modulating the antioxidant mechanisms.

Dietary Effects of Chromium Picolinate and Chromium Nanoparticles in Wistar Rats Fed with a High-Fat, Low-Fiber Diet: The Role of Fat Normalization

We aimed to evaluate how feeding a high-fat-low-fiber (F) diet to rats and dietary intervention with the implementation of a standard-fat-and-fiber (S) diet affects the response of the cardiovascular system to chromium (III) picolinate (Cr-Pic) and, alternatively, chromium nanoparticles (Cr-NPs). Young male Wistar Han rats (n/group = 12) from either the fatty group (18 weeks on F diet) or the intervention group (9 weeks on F diet + 9 weeks on S diet) received a pharmacologically relevant dose of 0.3 mg Cr/kg body weight in the form of Cr-Pic or Cr-NPs for 9 weeks. Our study on rats confirmed the pro-inflammatory effect of an F diet administered for 18 weeks. In the intervention group, both Cr-Pic and Cr-NPs decreased heart glutathione ratio (GSH+GSSG), enhanced participation of nitric oxide (NO) derived from inducible NO synthase (iNOS) in vascular relaxation to acetylcholine (ACh), increased the vasodilator net effect of cyclooxygenase-2 (COX-2)-derived prostanoids, and increased the production of superoxide anion (O₂^.-) in aortic rings. Meanwhile, in the fatty group, there was increased heart superoxide dismutase (SOD), decreased heart catalase (CAT), and reduced sensitivity in pre-incubated aortic rings to endogenous prostacyclin (PGI₂). The factors that significantly differentiated Cr-NPs from Cr-Pic were (i) decreased blood antioxidant capacity of water-soluble compounds (0.75-fold, p = 0.0205), (ii) increased hydrogen peroxide (H₂O₂) production (1.59-fold, p = 0.0332), and (iii) modified vasodilator response due to PGI₂ synthesis inhibition (in the intervention group) vs. modified ACh-induced vasodilator response due to (iv) COX inhibition and v) PGI₂ synthesis inhibition with thromboxane receptor blockage after 18 weeks on F diet (in the fatty group). Our results show that supplementation with Cr-Pic rather than with Cr-NPs is more beneficial in rats who regularly consumed an F diet (e.g., for 18 weeks). On the contrary, in the intervention group (9 weeks on F diet + 9 weeks of dietary fat normalization (the S diet)), Cr-Pic and Cr-NPs could function as pro-oxidant agents, initiating free-radical reactions that led to oxidative stress.

Nanoparticles, a Double-Edged Sword with Oxidant as Well as Antioxidant Properties—A Review

The usage of nanoparticles became inevitable in medicine and other fields when it was found that they could be administered to hosts to act as oxidants or antioxidants. These oxidative nanoparticles act as pro-oxidants and induce oxidative stress-mediated toxicity through the generation of free radicals. Some nanoparticles can act as antioxidants to scavenge these free radicals and help in maintaining normal metabolism. The oxidant and antioxidant properties of nanoparticles rely on various factors including size, shape, chemical composition, etc. These properties also help them to be taken up by cells and lead to further interaction with cell organelles/biological macromolecules, leading to either the prevention of oxidative damage, the creation of mitochondrial dysfunction, damage to genetic material, or cytotoxic effects. It is important to know the properties that make these nanoparticles act as oxidants/antioxidants and the mechanisms behind them. In this review, the roles and mechanisms of nanoparticles as oxidants and antioxidants are explained.

The Dietary Supplementation of Copper and Zinc Nanoparticles Improves Health Condition of Young Dairy Calves by Reducing the Incidence of Diarrhoea and Boosting Immune Function and Antioxidant Activity

This study was conducted to evaluate the effect of nano copper (nano Cu) and nano zinc (nano Zn) supplementation on the biomarkers of immunity and antioxidant and health status attributes in young dairy calves. Twenty-four young cattle calves were randomly assigned into four groups (6 calves per group) on a body weight and age basis for a period of 120 days. The feeding regimen was the same in all the groups except that these were supplemented with 0.0 mg nano Cu and nano Zn (control), 10 mg nano Cu (_nanoCu₁₀), 32 mg nano Zn (nanoZn₃₂), and a combination of nano Cu and nano Zn (_nanoCu₁₀ + _nanoZn₃₂) per kg dry matter (DM) basis in four respective groups. Supplementation of nano Cu along with nano Zn improves immune response which was evidenced from higher immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin A (IgA), total immunoglobulin (TIg), and Zn sulphate turbidity (ZST) units and lower plasma concentrations of tumour necrosis factor-α (TNF-α) and cortisol in the nanoCu10 + nanoZn32 group. There was no effect of treatment on the plasma concentrations of immunoglobulin E (IgE) and interferon-gamma (IFN-γ). Antioxidant status was also better in the nanoCu10 + nanoZn32 group as evidenced by lower concentrations of malondialdehyde (MDA) and higher activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), ceruloplasmin (Cp), and total antioxidant status (TAS). However, treatment did not exert any effect on catalase (CAT) activity. Although the nano Cu or nano Zn supplementation, either alone or in combination, did not exert any effect on growth performance or body condition score (BCS), the frequency of diarrhoea and incidence of diarrhoea were lower, while faecal consistency score (FCS) and attitude score were better in the _nanoCu₁₀ + _nanoZn₃₂ groups. In the control group, one calf was found affected with joint illness and two calves were found affected with navel illness. During the experimental period, none of the calves in all four groups were found to be affected by pneumonia. The findings of this study revealed that dietary supplementation of nano Cu in combination with nano Zn improved the health status of young dairy calves by improving immunity and antioxidant status.

Associations of Dietary and Plasma Copper Levels with Liver Function in a Chinese Population

The potential mechanisms underlying the association between copper (Cu) exposure and impaired liver function are unclear. This study aimed to investigate the potential associations of dietary Cu intake and plasma Cu levels with liver function biomarkers. A cross-sectional study was performed to assess liver function biomarkers-namely, levels of total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), alanine transaminase (ALT), and aspartate transaminase (AST)-in 2376 subjects in Guangxi, China. Dietary Cu intake was determined from a food frequency questionnaire containing 109 common foods. Plasma Cu concentrations were determined by inductively coupled plasma‒mass spectrometry. Multiple linear regression and multivariate restricted cubic splines (RCS) were used to evaluate the correlations of plasma Cu levels and dietary Cu levels with liver function biomarkers. The covariate-adjusted results of the linear regression analysis showed that plasma Cu levels were significantly negatively correlated with serum IBIL (β =  - 0.37), DBIL (β =  - 0.22), and TBIL levels (β =  - 0.32) (all p < 0.05), and dietary Cu was negatively correlated with serum AST levels (β =  - 0.12, p < 0.05). The RCS analysis further indicated a negative linear relationship between dietary Cu levels and AST levels. In summary, our results suggested that the plasma Cu level is associated with serum bilirubin levels and that dietary Cu intake is associated with serum AST levels. Further studies are needed to validate these associations and elucidate the underlying mechanisms.

Elucidation of Mechanisms in Cu (II) Caused Hypercontraction of Rat Tracheal Rings

Airway smooth muscle contraction is one of the primary factors involved in the initiation and progression of asthma which in turn is regulated by increased cytosolic Ca²⁺ concentration from intracellular stores and through transmembrane ion channels. Calcium-independent factors such as reactive oxygen species (ROS) generation, nitric oxide (NO) depletion and cyclooxygenase (COX) pathways also contribute to tracheal smooth muscle contraction. Studies on copper toxicity suggest significance of this essential micronutrient overdose in acute respiratory disorders, allergic asthma and ciliary motion in tracheal explants. However, the mechanism of copper caused hypercontraction upon direct exposure to tracheal smooth muscle is largely unknown. In this study we investigate the effect of copper exposure on isolated tracheal rings and relative contributions of various factors in acetylcholine-induced contractions. Results obtained suggest that rise in intracellular calcium concentration via voltage-operated Ca²⁺ channel (VOCC), store-operated Ca²⁺ channel (SOCC), stretch-activated channels (SAC) and TRP channel (transient receptor potential channel) activation is the major factor in copper-mediated hypercontraction. ROS generation or COX-dependent pathways do not appear to significantly contribute to Cu²⁺ caused hypercontraction.

Iron, Copper, and Zinc Homeostasis: Physiology, Physiopathology, and Nanomediated Applications

Understanding of how the human organism functions has preoccupied researchers in medicine for a very long time. While most of the mechanisms are well understood and detailed thoroughly, medicine has yet much to discover. Iron (Fe), Copper (Cu), and Zinc (Zn) are elements on which organisms, ranging from simple bacteria all the way to complex ones such as mammals, rely on these divalent ions. Compounded by the continuously evolving biotechnologies, these ions are still relevant today. This review article aims at recapping the mechanisms involved in Fe, Cu, and Zn homeostasis. By applying the knowledge and expanding on future research areas, this article aims to shine new light of existing illness. Thanks to the expanding field of nanotechnology, genetic disorders such as hemochromatosis and thalassemia can be managed today. Nanoparticles (NPs) improve delivery of ions and confer targeting capabilities, with the potential for use in treatment and diagnosis. Iron deficiency, cancer, and sepsis are persisting major issues. While targeted delivery using Fe NPs can be used as food fortifiers, chemotherapeutic agents against cancer cells and microbes have been developed using both Fe and Cu NPs. A fast and accurate means of diagnosis is a major impacting factor on outcome of patients, especially when critically ill. Good quality imaging and bed side diagnostic tools are possible using NPs, which may positively impact outcome.

The Role of 20-HETE, COX, Thromboxane Receptors, and Blood Plasma Antioxidant Status in Vascular Relaxation of Copper-Nanoparticle-Fed WKY Rats

Recently, the addition of copper nanoparticles (NPs) in a daily diet (6.5 mg/kg) was studied in different animal models as a possible alternative to ionic forms. Male Wistar-Kyoto rats (24-week-old, n = 11) were fed with copper, either in the form of carbonate salt (Cu_6.5) or metal-based copper NPs (NP_6.5), for 8 weeks. The third group was fed with a half dose of each (NP_3.25 + Cu_3.25). The thoracic aorta and blood plasma was studied. Supplementation with NP_6.5 decreased the Cu (×0.7), Cu/Zn-ratio (×0.6) and catalase (CAT, ×0.7), and increased Zn (×1.2) and superoxide dismutase (SOD, ×1.4). Meanwhile, NP_3.25 + Cu_3.25 decreased the Cu/Zn-ratio (×0.7), and CAT (×0.7), and increased the daily feed intake (×1.06). Preincubation with either the selective cyclooxygenase (COX)-2 inhibitor, or the non-selective COX-1/2 inhibitor attenuated vasodilation of rat thoracic aorta in the NP_6.5 group exclusively. However, an increased vasodilator response was observed in the NP_6.5 and NP_3.25 + Cu_3.25 group of rats after preincubation with an inhibitor of 20-hydroxyeicosatetraenoic acid (20-HETE) formation, and the thromboxane receptor (TP) antagonist. Significant differences were observed between the NP_6.5 and NP_3.25 + Cu_3.25 groups of rats in: dietary intake, acetylcholine-induced vasodilation, and response to COX-inhibitors. Copper NPs in a standard daily dose had more significant effects on the mechanism(s) responsible for the utilization of reactive oxygen species in the blood plasma with the participation of prostanoids derived from COX-2 in the vascular relaxation. Dietary copper NPs in both doses modified vasodilation through the vasoconstrictor 20-HETE and the TP receptors.

Entropy Production in Electroosmotic Cilia Facilitated Stream of Thermally Radiated Nanofluid with Ohmic Heating

No thermal process, even the biological systems, can escape from the long arms of the second law. All living things preserve entropy since they obtain energy from the nutrition they consume and gain order by producing disorder. The entropy generation in a biological and thermally isolated system is the main subject of current investigation. The aim is to examine the entropy generation during the convective transport of a ciliated nano-liquid in a micro-channel under the effect of a uniform magnetic field. Joint effects of electroosmosis and thermal radiation are also brought into consideration. To attain mathematical simplicity, the governing equations are transformed to wave frame where the inertial parts of the transport equations are dropped with the use of a long-wavelength approximation. This finally produces the governing equations in the form of ordinary differential equations which are solved numerically by a shooting technique. The analysis reports that the cilia motion contributes to enhance the flow and heat transfer phenomena. An enhancement in the flow is observed near the channel surface for higher cilia length and for smaller values of the electroosmotic parameter. The entropy generation in the ciliated channel is observed to be lessened by intensifying the thermal radiation and decreasing the Ohmic heating. The extended and flexible cilia structure contributes to augment the volumetric flow rate and to drop the total entropy generation in the channel.

The composition and vascular/antioxidant properties of Taraxacum officinale flower water syrup in a normal-fat diet using an obese rat model

ETHNOPHARMACOLOGICAL RELEVANCE

Taraxacum officinale (L.), commonly called dandelion has been used for centuries as a natural medicine to treat inflammatory diseases including some metabolic alterations associated with obesity.

AIM OF THE STUDY

Based on animal experiments this study aims to explore the potential mechanisms of action of T. officinale flower water syrup (TOFS) together with a normal-fat diet in the intervention of obesity.

MATERIALS AND METHODS

Obese male albino-Wistar rats (n = 8) at 25 weeks of age were fed with a normal-fat diet with or without added 27.82% TOFS (w/w) for 4 weeks. The reactivity of thoracic aorta and antioxidant capacity were studied.

RESULTS

TOFS delivered daily 926.8 μg of L-chicoric acid, 20.19 μg of luteolin and 3.379 ‬g of sucrose. TOFS showed beneficial effects by regulating blood lipids (HDL, x1.11-fold increase), thereby lowering the risk factors for atherosclerosis (TC/HDL, x0.90-fold). The antioxidant status was improved via an increase in plasma superoxide radical scavenging (SOD, x1.6-fold) and a decrease in lipid peroxidation (MDA, x0.81-fold). Moreover, the following were decreased: Cu (x0.53-fold), Zn (x0.72-fold) and the Cu/Zn molar ratio (x0.60-fold). A marker for liver damage/disease was beneficially decreased (ALP, x0.87-fold). TOFS modulated in a significant way COX-depended relaxation to ACh (p = 0.05) but not to CORM-2 (p = 0.1651) in isolated thoracic arteries, by decreased participation of vasoconstrictor prostanoids. The vascular contraction to prostaglandin F_2α was also decreased (x0.62-fold). We observed no change in the feed intake, body weight, organ-to-body weight ratio, blood glucose, CAT, FRAP, AST, ALT, TBARS/carbonyls (in heart, liver, kidneys, spleen) and carbonyls (in blood plasma, thoracic arteries); as well as F₂-isoprostanes in urine. Vascular response to the vasodilators ACh, SNP, A23187, CORM-2, pinacidil, NS-1619 and to the vasoconstrictors NA, U-46619, ET-1 as well as hyperpolarizing mechanism(s) were not modified.

CONCLUSIONS

TOFS possesses beneficial properties by regulating prostanoids and antioxidant status.

The Characterization of Ground Raspberry Seeds and the Physiological Response to Supplementation in Hypertensive and Normotensive Rats

This study aimed to evaluate the protective role of ground raspberry seeds (RBS) as a source of polyphenols and essential fatty acids on blood plasma enzymatic antioxidant status, lipid profile, and endothelium-intact vasodilation during physiological and pathological conditions. Young normotensive Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) at ten weeks of age were fed with either a control diet or were supplemented with added 7% RBS for six weeks (n = 6). The main component of RBS was dietary fiber (64%) and the main polyphenols were ellagitannins (1.2%) and flavan-3-ols (0.45%). Irrespective of the rat model, ground RBS decreased liver enzyme aspartate aminotransferase (0.9-fold) and hydrogen peroxide scavenging capacity (Catalase, 0.9-fold). In supplemented SHRs, preincubation with inducible nitric oxide synthase (iNOS) inhibitor 1400W, nonselective cyclooxygenase (COX) inhibitor indomethacin, selective COX-2 inhibitor NS-398, prostacyclin (PGI2) synthesis inhibitor tranylcypromine (TCP), thromboxane receptor (TP) antagonist SQ-29548, thromboxane synthesis inhibitor furegrelate, and 20-HETE synthesis inhibitor HET0016 induced the same relaxant response to acetylcholine as in the nonsupplemented control group. In supplemented WKYs, atherogenic index was decreased (0.8-fold), while iNOS and COX-2-derived PGI2 increased acetylcholine-induced vasodilation. These effects of ground RBS may constitute a potential mechanism for preventing cardiovascular diseases.

Dietary supplementation with copper nanoparticles influences the markers of oxidative stress and modulates vasodilation of thoracic arteries in young Wistar rats

We aimed to study the physiological effects of diet supplemented with copper (Cu) nanoparticles (NPs). During the eight weeks of the experiment, young Wistar rats (at seven weeks of age, n = 9) were supplemented with 6.5 mg of Cu either as NPs or carbonate salt (Cu6.5). A diet that was not supplemented with Cu served as a negative control (Cu0). The impact of nano Cu supplementation on lipid (reflected as thiobarbituric acid reactive substances-TBARS) and protein peroxidation (thiol and carbonyl groups) in blood plasma as well as the influence on the vasodilatory mechanism(s) of isolated rat thoracic arteries were studied. Supplementation with Cu enhanced lipid peroxidation (TBARS) in NP6.5 (x2.4) and in Cu6.5 (x1.9) compared to the negative control. Significant increase in TBARS was also observed in NP6.5 (x1.3) compared to the Cu6.5 group. The level of thiol groups increased in NP6.5 (x1.6) compared to Cu6.5. Meanwhile, significant (x0.6) decrease was observed in the Cu6.5 group compared to the negative control. Another marker of protein oxidation, carbonyl groups increased in NP6.5 (x1.4) and Cu6.5 (x2.3) compared to the negative control. However significant difference (x0.6) was observed between NP6.5 and Cu6.5. Arteries from Cu supplemented rats exhibited an enhanced vasodilation to gasotransmitters: nitric oxide (NO) and carbon monoxide (CO). An enhanced vasodilation to NO was reflected in the increased response to acetylcholine (ACh) and calcium ionophore A23187. The observed responses to ACh and CO releasing molecule (CORM-2) were more pronounced in NP6.5. The activator of cGMP-dependent protein kinases (8-bromo-cGMP) induced similar vasodilation of thoracic arteries in NP6.5 and Cu0 groups, while an increased response was observed in the Cu6.5 group. Preincubation with the inducible nitric oxide (iNOS) synthase inhibitor- 1400W, decreased the ACh-induced vasodilation in NP6.5, exclusively. Meanwhile the eicosanoid metabolite of arachidonic acid (20-HETE) synthesis inhibitor-HET0016, enhanced vasodilation of arteries from Cu0 group. In conclusion, this study demonstrates that supplementation with nano Cu influences oxidative stress, which further has modified the vascular response.

Resveratrol modulates the blood plasma levels of Cu and Zn, the antioxidant status and the vascular response of thoracic arteries in copper deficient Wistar rats

Copper (Cu) deficiency plays an important role in the development of cardiovascular disorders. Resveratrol (RSV) possesses pleiotropic cardiovascular benefits; however, the mechanism(s) by which RSV exerts protective effects are not completely understood. Male Wistar rats at 6 weeks of age were fed for 8 weeks with a Cu deficient diet (no added Cu, Cu = 0). In addition, Cu deficient rats were supplemented with RSV (500 mg/kg of diet, n = 9). Blood and intestinal samples were taken for further analysis together with internal organs and thoracic arteries. RSV supplementation resulted in elevated blood plasma levels of Cu (x2.1) and Zn (x1.1), in an increased activity of superoxide dismutase (SOD, x1.5) and ferric reducing antioxidant power (FRAP, x1.2). Meanwhile, markers of lipid peroxidation expressed as malondialdehyde (MDA, x1.5) and lipid hydroperoxides (LOOH, x1.1) were also increased in a significant way. Food intake, body weight, blood glucose, catalase, ceruloplasmin, lipid profile and intestinal samples were not modified. RSV enhanced the vasoconstriction of isolated thoracic arteries to noradrenaline (x1.4), potentiated the vasodilation to acetylcholine (ACh, x1.4) and increased the sensitivity to sodium nitroprusside (SNP). In addition, preincubation with the cyclooxygenase (COX)-inhibitor, indomethacin, potentiated the ACh-induced vasodilation, which was more pronounced in animals not supplemented with RSV. The K_ATP channel opener, pinacidil, induced a similar response in both studied groups. In conclusion, this study demonstrates that RSV supplementation influences oxidative stress and the antioxidant status, which may modify the vascular response in Cu deficiency.

The interaction between resveratrol and two forms of copper as carbonate and nanoparticles on antioxidant mechanisms and vascular function in Wistar rats

BACKGROUND

Experimental studies have emphasized that cardiovascular alterations can be improved by the long-term use of resveratrol (trans-3,5,4'-trihydroxystilbene; RSV) as well as dietary copper (Cu) intake.

METHODS

Male Wistar rats were supplemented for 8 weeks with Cu (6.5 mg/kg diet) as either nanoparticles (40 nm, CuNPs) or carbonate (CuCO3). Half of the studied animals were supplemented with RSV (500 mg/kg diet). Vascular function and blood plasma antioxidant status, expressed as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), lipid hydroperoxides (LOOH) and malondialdehyde (MDA) were analyzed. The activity of ceruloplasmin (Cp), lipid profile, fasting glucose, and concentrations of Cu and zinc (Zn) were analyzed.

RESULTS

RSV supplementation resulted in the elevated activity of SOD and decreased CAT, GPx and LDL-cholesterol in both groups. RSV supplementation on CuNPs increased the participation of vasoconstrictor prostanoids and decreased ACh-induced vasodilation, while the participation of hyperpolarizing mechanism(s) was restored by activating KATP channels. Blood plasma glucose was decreased. RSV supplementation on CuCO3 enhanced ACh- and SNP-induced vasodilation and decreased NA-induced vasoconstriction. The lipid profile was improved, as well as Zn concentration. Meanwhile, Cu and Cp, and the markers of lipid peroxidation, reflected as LOOH and MDA, were decreased.

CONCLUSION

The use of RSV during CuCO3 intake improves vascular responses, the lipid profile and the antioxidant mechanism(s). The beneficial role of RSV was not observed in the CuNP group and decreased ACh-induced vasodilation and increased participation of vasoconstrictor prostanoids in the vascular regulation were noticed.