Plasma Of Diabetic Rats Research Articles

Validated LC‐MS method for simultaneous quantitation of catalpol and harpagide in rat plasma: application to a comparative pharmacokinetic study in normal and diabetic rats after oral administration of Zeng‐Ye‐Decoction

A simple and efficient liquid chromatography-mass spectrometry (LC-MS) method was developed and validated for simultaneous quantitation of catalpol and harpagide in normal and diabetic rat plasma. Protein precipitation extraction with acetonitrile was carried out using salidroside as the internal standard (IS). The LC separation was performed on an Elite C18 column (150 × 4.6 mm, 5 µm) with the mobile phase consisting of acetonitrile and water within a runtime of 12.0 min. The analytes were detected without endogenous interference in the selected ion monitoring mode with positive electrospray ionization. Calibration curves offered satisfactory linearity (r > 0.99) at linear range of 0.05-50.0 µg/mL for catalpol and 0.025-5.0 µg/mL for harpagide with the lower limits of quantitation of 0.05 and 0.025 µg/mL, respectively. Intra- and inter-day precisions (RSD) were <9.4%, and accuracy (RE) was in the -6.6 to 4.9% range. The extraction efficiencies of catalpol, harpagide and IS were all >76.5% and the matrix effects of the analytes ranged from 86.5 to 106.0%. The method was successfully applied to the pharmacokinetic study of catalpol and harpagide after oral administration of Zeng-Ye-Decoction to normal and diabetic rats, respectively.

Potential nephrotoxic effects produced by steroidal saponins from hydro alcoholic extract of Tribulus terrestris in STZ-induced diabetic rats

Chronic hyperglycemia leads to the development of microvascular complications like diabetic nephropathy. The present study investigated the potential effects of the hydroalcoholic extract of Tribulus terrestris, a plant of Zygophyllaceae family, on the renal complications in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced by administering STZ (90 mg/kg) to the 2-days old neonates. After 6 weeks of induction, diabetic rats were treated with 50 mg/kg hydroalcoholic extract of T. terrestris for 8 weeks. The anti-hyperglycaemic nature was confirmed by reduction in blood glucose and improvement in insulin levels. Diabetic renal injury associated with decrease in total proteins and albumin levels was observed to be improved by T. terrestris extract. Glomerular filtration rate along with inflammatory and growth factors, adiponectin and erythropoietin were also improved by the treatment, though the findings were not significant. However, the beneficial antidiabetic effects of T. terrestris extract in plasma were not observed in kidney histopathology. This was confirmed by the quantitative estimation of unhydrolyzed fraction of saponins (major component: protodioscin) in plasma and kidney samples of normal and diabetic rats. Hence, it can be concluded that 8 weeks treatment with T. terrestris extract produces potential toxic effects in kidney, which are independent of its anti-diabetic action.

Treatment with hydrogen sulfide alleviates streptozotocin‐induced diabetic retinopathy in rats

Retinopathy, as a common complication of diabetes, is a leading cause of reduced visual acuity and acquired blindness in the adult population. The aim of present study was to investigate the therapeutic effect of hydrogen sulfide on streptozotocin (STZ)-induced diabetic retinopathy in rats. Rats were injected with a single i.p. injection of STZ (60 mg·kg⁻¹) to induce diabetic retinopathy. Two weeks later, the rats were treated with NaHS (i.p. injection of 0.1 mL·kg⁻¹·d⁻¹ of 0.28 mol·L⁻¹ NaHS, a donor of H₂S) for 14 weeks. Treatment with H₂S had no significant effect on blood glucose in STZ-induced diabetic rats. Treatment with exogenous H₂S enhanced H₂S levels in both plasma and retinas of STZ-induced diabetic rats. Treatment with H₂S in STZ-treated rats improved the retinal neuronal dysfunction marked by enhanced amplitudes of b-waves and oscillatory potentials and expression of synaptophysin and brain-derived neurotrophic factor, alleviated retinal vascular abnormalities marked by reduced retinal vascular permeability and acellular capillary formation, decreased vitreous VEGF content, down-regulated expressions of HIF-1α and VEGFR2, and enhanced occludin expression, and attenuated retinal thickening and suppressed expression of extracellular matrix molecules including laminin β1 and collagen IVα3 expression in retinas of STZ-induced diabetic rats. Treatment with H₂S in retinas of STZ-induced diabetic rats abated oxidative stress, alleviated mitochondrial dysfunction, suppressed NF-κB activation and attenuated inflammation. Treatment with H₂S alleviates STZ-induced diabetic retinopathy in rats possibly through abating oxidative stress and suppressing inflammation.

Effect of Green and Degree of Roasted Arabic Coffee on Hyperlipidemia and Antioxidant Status in Diabetic Rats

This study aims to examine the effects of green and different roasted degree of Arabic coffee on alloxan induced diabetes in rats. Animals were allocated into five groups of six rats each: a normal control group, diabetic group, diabetic rats fed with green Arabic coffee, diabetic rats fed with light roasted coffee and diabetic rats fed with dark roasted coffee group. The results showed increasing roasting degrees led to a decrease in moisture, radicalscavenging activity and total phenols. The diabetic rats presented a significant increase in blood glucose, plasma lipid profile compared to the control group. In addition, plasma malonaldialdehyde levels significantly increased compared to normal control group. Antioxidant enzymes activities such as superoxide dismutase and reduced Glutathione (GSH) levels significantly decreased in the plasma of diabetic rats compared to normal controls. The results showed that the experimental rats supplemented by green and roasted Arabic coffee significant increased feed efficiency ratio than diabetic control group. At the end of the study period, the experimental rats were showed significant improvement in blood glucose. It is noted that green coffee bean group has the best effect in decreasing glucose level followed by light coffee group followed by dark coffee group which recorded 95.46, 119.17 and 201.46 mg/dL, respectively. Experimental rats supplemented by green and light roasted Arabic coffee were similar insulin concentration normal control group. All treated groups showed a significant decrease in TC, TL, TG and LDL-C, while a significant increase HDL compared with diabetic control group with the highest value for green coffee. The diabetic rat supplemented by dark coffee was lower effective against lipids profile than green and light coffee. Diet supplemented with green and roasted Arabic coffee in the diabetic rats ameliorated antioxidant enzymes activities and level of GSH in diabetic rats and significantly decreased MDA levels. The administration of Arabic coffee attenuated the increased levels of the plasma enzymes produced by the induction of diabetes and caused a subsequent recovery towards normalization comparable to the control group animals. Our results thus suggest that green and light roasted Arabic coffee supplemented may be helpful in preventing diabetic complications in adult rats.

Application of two‐dimensional electrophoresis for plasma of normal and diabetic rats

The aim of this study was to compare plasma gels of normal and diabetic rats by two‐dimensional electrophoresis. Experimental animals were randomly divided into two groups (n = 8): G1 = control and G2 = diabetic rats (induced by intraperitoneal administration of streptozotocin in a single dose concentration of 60 mg/kg body weight). A pool of plasma samples were diluted in a specific buffer and applied to IEF (isoelectric focusing) strips with pH in the range of 4–7. Once hydrated for 12h, the strips were brought to the IEF system for running the first dimension. After this step, the strips were equilibrated in a specific buffer for 15 minutes and applied onto polyacrylamide gels at 10% w/v for running the second dimension. At the end of the separation steps (performed in duplicate), the protein spots were fixed in the gel and then stained with Coomassie Blue. The gels were scanned and analyzed using an image processor. For the image analysis, it was found that the protein spots for both experimental groups were more concentrated in the range of 24–76 kDa; 416 spots were found in G1 and 513 in G2, with a percentual matching of 53 and 43% for G1 and G2 respectively. These matching values show that there was some difference between the treatments. There is great interest in the plasma proteome as a discovery source of new biomarkers in diabetes as it is thought to contain subsets of other tissue proteomes.Financial Support: FAPESP 2011/21672–1

Increase in Secretory Sphingomyelinase Activity and Specific Ceramides in the Aorta of Apolipoprotein E Knockout Mice during Aging

Atherosclerosis is caused by many factors, one of which is oxidative stress. We recently demonstrated that systemic oxidative stress increased secretory sphingomyelinase (sSMase) activity and generated ceramides in the plasma of diabetic rats. In addition, we also showed that the total ceramide level in human plasma correlated with the level of oxidized low-density lipoprotein. To investigate the relationship between ceramide species and atherogenesis during aging, we compared age-related changes in ceramide metabolism in apolipoprotein E knock out mice (apoE(-/-)) and wild type mice (WT). Although the total plasma ceramide level was higher in apoE(-/-) than that in WT at all ages, it decreased with increasing age. sSMase activity increased at 65 weeks (w) of age in both strains of mice. When apoE(-/-) developed atherosclerosis at 15 w of age, C18:0, C22:0, and C24:0 ceramide levels in the apoE(-/-) aorta significantly increased. Furthermore, at 65 w of age C16:0 and C24:1 ceramide levels were significantly higher than those in WT. These results suggested that elevation in levels of specific ceramide species due to sSMase activity contributed to atherogenesis during aging.

Fisetin averts oxidative stress in pancreatic tissues of streptozotocin-induced diabetic rats

Persistent hyperglycemia is associated with chronic oxidative stress which contributes to the development and progression of diabetes-associated complications. The sensitivity of pancreatic β-cells to oxidative stress has been attributed to their low content of antioxidants compared with other tissues. Bioactive compounds with potent antidiabetic properties have been shown to ameliorate hyperglycemia mediated oxidative stress. Recently, we have reported that oral administration of fisetin (10 mg/Kg b.w.), a bioflavonoid found to be present in strawberries, persimmon, to STZ-induced experimental diabetic rats significantly improved normoglycemia. The present study was aimed to evaluate the antioxidant potential of fisetin in both in vitro and in vivo. Diabetes was induced by single intraperitoneal injection of streptozotocin (50 mg/kg body weight). Fisetin was administered orally for 30 days. At the end of the study, all animals were killed. Blood samples were collected for the biochemical estimations. The antioxidant status was evaluated. Histological examinations were performed on pancreatic tissues. Fisetin treatment showed a significant decline in the levels of blood glucose, glycosylated hemoglobin (HbA1c), NF-kB p65 unit (in pancreas) and IL-1β (plasma), serum nitric oxide (NO) with an elevation in plasma insulin. The treatment also improved the antioxidant status in pancreas as well as plasma of diabetic rats indicating the antioxidant potential of fisetin. In addition, the results of DPPH and ABTS assays substantiate the free radical scavenging activity of fisetin. Histological studies of the pancreas also evidenced the tissue protective nature of fisetin. It is concluded that, fisetin possesses antioxidant and anti-inflammatory property and may be considered as an adjunct for the treatment of diabetes.

Beneficial effects of flaxseed oil and fish oil diet are through modulation of different hepatic genes involved in lipid metabolism in streptozotocin–nicotinamide induced diabetic rats

Dietary omega-3 fatty acids have been demonstrated to have positive physiological effects on lipid metabolism, cardiovascular system and insulin resistance. Type-2 diabetes (T2DM) is known for perturbations in fatty acid metabolism leading to dyslipidemia. Our objective was to investigate beneficial effects of dietary flaxseed oil and fish oil in streptozotocin-nicotinamide induced diabetic rats. Thirty-six adult, male, Wistar rats were divided into six groups: three diabetic and three non-diabetic. Diabetes was induced by an injection of nicotinamide (110mg/kg) and STZ (65mg/kg). The animals received either control, flaxseed oil or fish oil (10% w/w) enriched diets for 35days. Both diets lowered serum triglycerides and very low-density lipoprotein cholesterol levels and elevated serum high-density lipoprotein cholesterol levels in diabetic rats, while serum total cholesterol and LDL-C levels remained unaffected. Both the diets increased omega-3 levels in plasma and RBCs of diabetic rats. Flaxseed oil diet significantly up-regulated the key transcription factor peroxisome proliferator-activated receptor-α (PPAR-α ) and down-regulated sterol regulatory element-binding protein-1 (SREBP-1) in diabetic rats, which would have increased β-oxidation of fatty acids and concomitantly reduced lipogenesis respectively, thereby reducing TG levels. Fish oil diet, on the contrary lowered serum TG levels without altering PPAR-α while it showed a non-significant reduction in SREBP-1 expression in diabetic rats. Another key finding of the study is the activation of D5 and D6 desaturases in diabetic rats by flaxseed oil diet or fish oil diets, which may have resulted in an improved omega-3 status and comparable effects shown by both diets. The reduced expression of Liver-fatty acid binding protein in diabetic rats was restored by fish oil alone, while both diets showed equal effects on adipocyte fatty acid-binding protein expression. We also observed down-regulation of atherogenic cytokines tumor necrosis factor-α and interleukin-6 by both the diets. In conclusion, dietary flaxseed oil and fish oil have therapeutic potential in preventing lipid abnormalities in T2DM.

Chromium picolinate attenuates hyperglycemia-induced oxidative stress in streptozotocin-induced diabetic rats

Chromium picolinate is advocated as an anti-diabetic agent for impaired glycemic control. It is a transition metal that exists in various oxidation states and may thereby act as a pro-oxidant. The present study has been designed to examine the effect of chromium picolinate supplementation on hyperglycemia-induced oxidative stress. Diabetes was induced in male Wistar rats by a single intraperitoneal injection of streptozotocin (50mg/kg body weight) and chromium was administered orally as chromium picolinate (1mg/kg body weight) daily for a period of four weeks after the induction of diabetes. As is characteristic of diabetic condition, hyperglycemia was associated with an increase in oxidative stress in liver in terms of increased lipid peroxidation and decreased glutathione levels. The activity of antioxidant enzymes like superoxide dismutase, catalase and glutathione reductase were significantly reduced in liver of diabetic animals. Levels of α-tocopherol and ascorbic acid were found to be considerably lower in plasma of diabetic rats. Chromium picolinate administration on the other hand was found to have beneficial effect in normalizing glucose levels, lipid peroxidation and antioxidant status. The results from the present study demonstrate potential of chromium picolinate to attenuate hyperglycemia-induced oxidative stress in experimental diabetes.

Determination of metformin in diabetic rat plasma by an improved ion-pair high-performance liquid chromatography: application to a pharmacokinetic study

Determination of metformin in diabetic rat plasma by an improved ion-pair high-performance liquid chromatography: application to a pharmacokinetic study

Ceramide profiles in the brain of rats with diabetes induced by streptozotocin

Diabetes is associated with disturbances of brain activity and cognitive impairment. We hypothesize that ceramides may constitute an important contribution to diabetes-linked neuro-dysfunction. In our study we used rats injected with streptozotocin (STZ) as a model of severe hyperglycemia. Using the gas-liquid chromatography technique we found a significant increase of ceramide content in brains and a decrease in plasma of diabetic rats. The inhibitor of serine palmitoyltransferase, myriocin, reduced ceramide generation in hyperglycemic brains, although injected alone it exerted a paradoxical effect of ceramide upregulation. Myriocin had no impact on ceramide concentration in the plasma of either control or diabetic rats. The level of ceramide saturated fatty acids was elevated whereas the level of ceramide poly-unsaturated fatty acids was downregulated in brains of all experimental groups. The concentration of ceramide mono-unsaturated fatty acids remained unchanged. The pattern of individual ceramide species was altered depending on treatment. We noted an STZ-evoked increase of brain ceramide C16:0, C18:0 and C20:0 and a strong decline in ceramide C18:2 fatty acid levels. Some changes of brain ceramide pattern were modified by myriocin. We found a decreased amount of total ceramide-ω-6 fatty acids in STZ-treated rat brains and no changes in ceramide-ω-3 concentration. We conclude that ceramides may be important mediators of diabetes-accompanied brain dysfunction.

Effects of rosemary on lipid profile in diabetic rats

This study was to determine the mechanism underlying the hypoglycaemic activity of the aqueous extract perfusion of rosemary in normal and streptozotocin-induced diabetic rats. The sugar level and lipid profile were investigated in plasma of normal and streptozotocin-induced diabetic rats treated with rosemary for four weeks. Diabetic rats exhibited an increase in the levels of sugar, cholesterol, triglycerides and low density lipoprotein (LDL), and a decrease in the level of high density lipoprotein (HDL). The administration of rosemary showed a decrease of 20% in sugar level, 22% cholesterol, 24% triglycerides, 27% (LDL), and increase 18% in (HDL). The findings of this study indicate that the administration of rosemary shows better lipid profile as well as decrease in the sugar level in both normal and diabetic rats.

English

This study was to determine the mechanism underlying the hypoglycaemic activity of the aqueous extract perfusion of&nbsp;rosemary&nbsp;in normal and streptozotocin-induced diabetic rats. The sugar level and lipid profile were investigated in plasma of normal andstreptozotocin-induced diabetic rats treated with rosemary for four weeks. Diabetic rats exhibited an increase in the levels of sugar, cholesterol, triglycerides and low density lipoprotein (LDL), and a decrease in the level of high density lipoprotein (HDL). The administration of rosemary showed a decrease of 20% in sugar level, 22% cholesterol, 24% triglycerides, 27% (LDL), and increase 18% in (HDL). The findings of this study indicate that the administration of rosemary shows better lipid profile as well as decrease in the sugar level in both normal and diabetic rats. &nbsp; Key words:&nbsp;Diabetes, rosemary, lipid profile.

A polysaccharide from Acanthopanax senticosus improves the antioxidant status in alloxan-induced diabetic mice

The effects of Acanthopanax senticosus polysaccharide (ASP) on antioxidant status had been investigated both in vitro and in alloxan-induced diabetic mice. In vitro antioxidant assays, ASP had a potent scavenging ability to superoxide radical and hydroxyl radicals. In vivo experiment, male Wistar rats were made diabetic by injection of alloxan and ASP (50, 100 and 200 mg/kg) was administered to diabetic mice for two months. ASP treatment could significantly and dose-dependently reduce the levels of lipid peroxidation markers, namely thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LP), and elevate enzymic antioxidants, such as superoxide dismutase (SOD) and catalase (CAT) activities in the plasma, liver, kidney and heart of diabetic rats. Moreover, increased level of serum insulin and decreased level of blood glucose (FBG) were observed in the plasma of diabetic control rats. The results demonstrated that ASP oral administration had an efficacious amelioration effect on the antioxidant status in alloxan-induced diabetic mice.

Effects of N-Acetylcysteine on Nicotinamide Dinucleotide Phosphate Oxidase Activation and Antioxidant Status in Heart, Lung, Liver and Kidney in Streptozotocin-Induced Diabetic Rats

PurposeHyperglycemia increases reactive oxygen species (ROS) and the resulting oxidative stress plays a key role in the pathogenesis of diabetic complications. Nicotinamide dinucleotide phosphate (NADPH) oxidase is one of the major sources of ROS production in diabetes. We, therefore, examined the possibility that NADPH oxidase activation is increased in various tissues, and that the antioxidant N-acetylcysteine (NAC) may have tissue specific effects on NADPH oxidase and tissue antioxidant status in diabetes.Materials and MethodsControl (C) and streptozotocin-induced diabetic (D) rats were treated either with NAC (1.5 g/kg/day) orally or placebo for 4 weeks. The plasma, heart, lung, liver, kidney were harvested immediately and stored for biochemical or immunoblot analysis.Resultslevels of free 15-F2t-isoprostane were increased in plasma, heart, lung, liver and kidney tissues in diabetic rats, accompanied with significantly increased membrane translocation of the NADPH oxidase subunit p67phox in all tissues and increased expression of the membrane-bound subunit p22phox in heart, lung and kidney. The tissue antioxidant activity in lung, liver and kidney was decreased in diabetic rats, while it was increased in heart tissue. NAC reduced the expression of p22phox and p67phox, suppressed p67phox membrane translocation, and reduced free 15-F2t-isoprostane levels in all tissues. NAC increased antioxidant activity in liver and lung, but did not significantly affect antioxidant activity in heart and kidney.ConclusionThe current study shows that NAC inhibits NADPH oxidase activation in diabetes and attenuates tissue oxidative damage in all organs, even though its effects on antioxidant activity are tissue specific.

Antihyperglycemic effect of iridoid glucoside, isolated from the leaves of Vitex negundo in streptozotocin-induced diabetic rats with special reference to glycoprotein components

The aim of present study was to isolate an iridoid glucoside from the leaves of Vitex negundo and evaluates its effects on dearrangement in plasma and tissues glycoprotein components in streptozotocin-induced diabetic rats. The levels of blood glucose, plasma and tissues glycoproteins such as hexose, hexosamine, fucose and sialic acid were significantly increased whereas plasma insulin levels were significantly decreased in diabetic rats. On oral administration of iridoid glucoside at a concentration of 50mg/kg b.w. once daily to diabetic rats for the period of 30days, reversed the above-mentioned hyperglycemia-induced biochemical changes to near normal levels. The anti-hyperglycemic effect of iridoid glucoside was comparable with glibenclamide, a known hypoglycemic drug. Based on the results obtained from the present study, it may be concluded that iridoid glucoside possesses significant productive effect on glycoprotein metabolism in addition to its antidiabetic effect.

Evaluation of the anti–diabetic properties of Mucuna pruriens seed extract

Objective To explore the antidiabetic properties of Mucuna pruriens( M. pruriens). Methods Diabetes was induced in Wistar rats by single intravenous injection of 120 mg/kg of alloxan monohydrate and different doses of the extract were administered to diabetic rats. The blood glucose level was determined using a glucometer and results were compared with normal and untreated diabetic rats. The acute toxicity was also determined in albino mice. Results Results showed that the administration of 5, 10, 20, 30, 40, 50, and 100 mg/kg of the crude ethanolic extract of M. pruriens seeds to alloxan-induced diabetic rats (plasma glucose > 450 mg/dL) resulted in 18.6%, 24.9%, 30.8%, 41.4%, 49.7%, 53.1% and 55.4% reduction, respectively in blood glucose level of the diabetic rats after 8h of treatment while the administration of glibenclamide (5 mg/kg/day) resulted in 59.7% reduction. Chronic administration of the extract resulted in a significant dose dependent reduction in the blood glucose level ( P<0.001). It also showed that the antidiabetic activity of M. pruriens seeds resides in the methanolic and ethanolic fractions of the extract. Acute toxicity studies indicated that the extract was relatively safe at low doses, although some adverse reactions were observed at higher doses (8-32 mg/kg body weight), no death was recorded. Furthermore, oral administration of M. pruriens seed extract also significantly reduced the weight loss associated with diabetes. Conclusions The study clearly supports the traditional use of M. pruriens for the treatment of diabetes and indicates that the plant could be a good source of potent antidiabetic drug.

Differential carbonylation of proteins as a function of in vivo oxidative stress.

This study reports for the first time qualitative and quantitative differences in carbonylated proteins shed into blood as a function of increasing levels of OS. Carbonylated proteins in freshly drawn blood from pairs of diabetic and lean rats were derivatized with biotin hydrazide, dialyzed, and enriched with avidin affinity chromatography. Proteins thus selected were used in several ways. Differences between control and diabetic subjects in relative concentration of proteins was achieved by differential labeling of tryptic digests with iTRAQ reagents followed by reversed phase chromatography (RPC) and tandem mass spectrometry (MS/MS). Identification and characterization of OS induced post-translational modification sites in contrast was achieved by fractionation of affinity selected proteins before proteolysis and RPC-MS/MS. Relative quantification of peptides bearing oxidative modifications was achieved for the first time by selective reaction monitoring (SRM). Approximately 1.7% of the proteins in Zucker diabetic rat plasma were selected by the avidin affinity column as compared to 0.98% in lean animal plasma. Among the 35 proteins identified and quantified, Apo AII, clusterin, hemopexin precursor, and potassium voltage-gated channel subfamily H member 7 showed the most dramatic changes in concentration. Seventeen carbonylation sites were identified and quantified, 11 of which changed more than 2-fold in oxidation state. Three types of carbonylation were identified at these sites: direct oxidative cleavage from reactive oxygen species, glycation and addition of advanced glycation end products, and addition of lipid peroxidation products. Direct oxidation was the dominant form of carbonylation observed while hemoglobin and murinoglobulin 1 homologue were the most heavily oxidized proteins.

Oxidative Stress Plays Important Role on Cardiac Ryanodine Receptor Calcium Release Channels in Diabetic Rats

Reactive oxygen species play an important role in the development of diabetic cardiomyopathy due to alteration of Ca2+ signaling via changes in critical processes that regulate contractile activity of heart. Since these defects result partially from a dysfunction of cardiac ryanodine receptor calcium release channels (RyR2s), the present study was aimed to examine whether protective effect of in vivo administration of sodium selenate on contractile activity of heart from diabetic rats via affecting the hyperphosphorylation level of RyR2s and their a number of accessory proteins. Selenium normalized prolonged action potential duration and improved depressed tension obtained with electrically stimulated papillary muscle from diabetic rat hearts. Moreover, selenium reduced the increased oxidative stress and depressed oxtioxidant defence system in both plasma and heart tissue of diabetic rats. Western-blot data indicated that sodium selenate-treatment prevented markedly hyperphosphorylation of RyR2s, and activations of PKA, CaMKII and NF-κB as well as reduction in Trx level of the diabetic rat hearts. In the present study, we demonstrated that the mechanisms responsible for the cardioprotective effects of sodium selenate in the diabetic myocardium include preservation of oxidative stress-induced hyperphosphorylation and activation of Ca2+ signaling proteins, as well as with a normalization of NF-κB. Therefore, such an observation provides evidences for a potential therapeutic usage of selenium compounds in the amelioration of cardiovascular disorders in diabetes (Supported by TUBITAK SBAG-107S304).

Influence of thymoquinone on glycoprotein changes in experimental hyperglycemic rats

Aim: The present study was designed to investigate the effect of thymoquinone (TQ) on the levels of glycoprotein components in plasma and tissues of streptozotocin (STZ)-nicotinamide (NA)-induced diabetic rats. Materials and Methods: Diabetes was induced in experimental rats by a single intraperitoneal (i.p) injection of STZ (45 mg/kg b.w) dissolved in 0.1 M citrate buffer (pH 4.5) 15 minutes after the i.p injection of NA (110 mg/kg b.w). Results: The levels of hexose, hexosamine, fucose, and sialic acid were estimated in plasma, liver, and kidney tissues of experimental rats. An increase in glycoprotein components in plasma was noticed in diabetic rats. In hepatic and renal tissues, a significant decrease in sialic acid with increases in hexose, hexosamine, and fucose levels were observed in diabetic rats when compared with control animals. Oral administration of TQ at 80 mg/kg b.w. for 45 days significantly ameliorated the glycoprotein changes in plasma and tissues of diabetic rats. Conclusion: The results of the present study show the potent beneficial effects of TQ in modifying the levels of glycoprotein components in plasma and tissues of diabetic rats.