scholarly journals Epigallocatechin-3-gallate ameliorates glucolipid metabolism and oxidative stress in type 2 diabetic rats

2020 ◽  
Vol 17 (6) ◽  
pp. 147916412096699
Author(s):  
Wenru Li ◽  
Chaonan Zhu ◽  
Tianheng Liu ◽  
Weifang Zhang ◽  
Xu Liu ◽  
...  

Aims: The objective of this study was to explore the effects of epigallocatechin-3-gallate (EGCG) on type 2 diabetes mellitus (T2DM). Main methods: Male Sprague–Dawley rats were allocated into six groups. The control group received a conventional diet. The diabetic group received a high-sucrose high-fat (HSHF) diet for 4 weeks and then was fasted and injected with streptozotocin (STZ); subsequently, the rats received a HSHF diet for another 4 weeks to develop diabetes. The four treatment groups were diabetic rats that received intragastric metformin (500 mg/kg/day) or EGCG (25, 50, and 100 mg/kg/day) for 10 weeks. All groups except the control group received a HSHF diet throughout the experiment. Several biochemical parameters such as fasting blood glucose (FBG), postprandial blood glucose (PBG), liver glycogen, muscle glycogen, fasting serum insulin (FSI), homeostasis model of insulin resistance (HOMA-IR), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), free fatty acids (FFA), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured to assess the effects of EGCG on glycemic control, insulin resistance, lipid profile, and oxidative stress. Furthermore, oxidative stress in pancreatic islet β cells was detected by dihydroethidium staining. Key findings: A HSHF diet and STZ injection induced T2DM, as indicated by changed blood glucose and body weight, which was accompanied by insulin resistance, an altered lipid profile, and oxidative stress. Interestingly, EGCG treatment dose-dependently recovered these indexes. Significance: EGCG successfully ameliorated glycemic control and insulin sensitivity while reducing the lipid profile and oxidative stress in a T2DM rat model.

2020 ◽  
Vol 20 (7) ◽  
pp. 1117-1132
Author(s):  
Abdelaziz M. Hussein ◽  
Elsayed A. Eid ◽  
Ismaeel Bin-Jaliah ◽  
Medhat Taha ◽  
Lashin S. Lashin

Background and Aims: In the current work, we studied the effects of exercise and stevia rebaudiana (R) extracts on diabetic cardiomyopathy (DCM) in type 2 diabetic rats and their possible underlying mechanisms. Methods: : Thirty-two male Sprague Dawley rats were randomly allocated into 4 equal groups; a) normal control group, b) DM group, type 2 diabetic rats received 2 ml oral saline daily for 4 weeks, c) DM+ Exercise, type 2 diabetic rats were treated with exercise for 4 weeks and d) DM+ stevia R extracts: type 2 diabetic rats received methanolic stevia R extracts. By the end of the experiment, serum blood glucose, HOMA-IR, insulin and cardiac enzymes (LDH, CK-MB), cardiac histopathology, oxidative stress markers (MDA, GSH and CAT), myocardial fibrosis by Masson trichrome, the expression of p53, caspase-3, α-SMA and tyrosine hydroxylase (TH) by immunostaining in myocardial tissues were measured. Results: T2DM caused a significant increase in blood glucose, HOMA-IR index, serum CK-MB and LDH, myocardial damage and fibrosis, myocardial MDA, myocardial α-SMA, p53, caspase-3, Nrf2 and TH density with a significant decrease in serum insulin and myocardial GSH and CAT (p< 0.05). On the other hand, treatment with either exercise or stevia R extracts significantly improved all studied parameters (p< 0.05). Moreover, the effects of stevia R was more significant than exercise (p< 0.05). Conclusion: Both exercise and methanolic stevia R extracts showed cardioprotective effects against DCM and Stevia R offered more cardioprotective than exercise. This cardioprotective effect of these lines of treatment might be due to attenuation of oxidative stress, apoptosis, sympathetic nerve density and fibrosis and upregulation of the antioxidant transcription factor, Nrf2.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Yajing Li ◽  
Minli Chen ◽  
Hongzhuan Xuan ◽  
Fuliang Hu

The present study investigates the encapsulated propolis on blood glycemic control, lipid metabolism, and insulin resistance in type 2 diabetes mellitus (T2DM) rats. The animal characteristics and biological assays of body weight, fasting blood glucose (FBG), fasting serum insulin (FINS), insulin act index (IAI), triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) were measured and euglycemic hyperinsulinemic glucose clamp technique were used to determine these effects. Our findings show that oral administration of encapsulated propolis can significantly inhibit the increasing of FBG and TG in T2DM rats and can improve IAI and M value in euglycemic hyperinsulinemic clamp experiment. There was no significant effects on body weight, TC, HDL-C, and LDL-C in T2DM rats treated with encapsulated propolis. In conclusion, the results indicate that encapsulated propolis can control blood glucose, modulate lipid metabolism, and improve the insulin sensitivity in T2DM rats.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Shiqin Peng ◽  
Ping Wei ◽  
Qun Lu ◽  
Rui Liu ◽  
Yue Ding ◽  
...  

The effects of propolis on blood glucose regulation and the alleviation of various complications caused by diabetes have been widely studied. The main source of propolis in the northern temperate zone is poplar buds. However, there is limited research on the antidiabetic activity of poplar buds. In order to evaluate the effect of poplar buds on type-2 diabetes, crude extract and 50% fraction of poplar buds were used to feed streptozotocin-induced type-2 diabetic mice. The results showed that 50% fraction could increase insulin sensitivity and reduce insulin resistance, as well as decrease the levels of fasting blood glucose, glycated hemoglobin, and glycosylated serum proteins in diabetic mice. Compared with the model control group, the 50% fraction-treated group showed significant decreases of malondialdehyde (MDA) and increases of superoxide dismutase (SOD) in serum and liver homogenate. Moreover, 50% fraction could significantly decrease total cholesterol (TC), alleviate abnormal lipid metabolism, and enhance antioxidant capacity in the serum. For inflammatory factors, feeding of 50% fraction could also reduce the levels of interleukin 6 (IL-6), tumor necrosis factorα(TNF-α), monocyte chemotactic protein 1 (MCP-1), and cyclooxygenase-2 (COX-2) in liver homogenate. Taken together, our results suggest that crude extract and 50% fraction of poplar buds, particularly the latter, can decrease blood glucose levels and insulin resistance, and 50% fraction can significantly relieve dyslipidemia, oxidative stress, and inflammation caused by type-2 diabetes.


Author(s):  
Ojoye N. Briggs ◽  
Kemzi N. Elechi-amadi ◽  
Justice C. Ohaka ◽  
Edna O. Nwachuku ◽  
Bartimaeus S. Ebirien-agana

Aim: This study evaluated the effects of metformin in combination with a herbal capsule (glucoblock) on insulin resistance and oxidative stress index in type 2 diabetic rats. Methodology: A total of 35 male Wistar albino rats weighing between 120-220 g were used for this study. The rats were placed on high fat diet, and diabetes was induced by a single intraperitoneal injection of freshly prepared streptozotocin (STZ) (45 mg/kg body wt). Fasting plasma glucose (FPG) was determined using the glucose oxidase method. Fasting plasma insulin (FPI), total oxidant status (TOS), total antioxidant status (TAS) and superoxide dismutase (SOD) levels were quantitatively determined by a rat-specific sandwich-enzyme linked immunosorbent assay (ELISA) method. Insulin resistance (IR) was determined using the homeostatic model assessment for insulin resistance (HOMA-IR) method. Oxidative stress index (OSI) was determined by the ratio of TOS to TAS. Phytochemical analysis on the herbal capsule was done using classical methods. Results: The results revealed the presence of alkaloids (100.31μg/mg), flavonoids (131.45μg/mg), cardiac glycosides (55.93μg/mg) and saponins (61.47μg/mg) in the herbal drug glucoblock. The results showed significantly lower FPG levels in the treatment groups when compared to the diabetic control. Group 3 administered metformin had significantly higher FPG levels compared to the negative control. Group 4 administered the herbal drug glucoblock and group 5 administered a combination of metformin and glucoblock, showed no significant differences in FPG levels when compared to the negative control. The diabetic control had significantly higher FPI levels compared to the negative control and treatment groups. The treatment groups showed no significant differences in FPI levels when compared to the negative control. HOMA-IR was significantly higher in the diabetic control compared to the negative control and treatment groups. Also, HOMA-IR values in the treatment groups showed no significant difference compared to the negative control except for group 3 (metformin), that was significantly higher than the negative control. SOD was significantly lower in the diabetic control, compared to the negative control and treatment groups. There were no significant differences in SOD levels in the treatment groups compared to the negative control. TOS levels in the negative control group and treatment groups were significantly lower, compared to the diabetic control. TAS was significantly lower in the diabetic control and treatment groups compared to the negative control. OSI in the diabetic control was significantly higher, compared to the negative control and treatment groups. Also, the treatment groups had significantly higher OSI compared to the negative control. Conclusion: High fat diet and streptozotocin induction produced significant insulin resistance and oxidative stress in the diabetic rats. Glucoblock was more effective in reducing insulin resistance compared to metformin. The combination showed synergistic drug-herb reaction as glucoblock potentiated the actions of metformin. Both showed antioxidant potential but were not effective in lowering oxidative stress to normal levels. There is need to incorporate antioxidant therapy in the treatment protocol for diabetes mellitus.


Author(s):  
Azizollah Pourmahmoudi ◽  
Mohammad Sharif Talebianpoor ◽  
Tahereh Vafaiee Nejad ◽  
Mahnaz Mozafari ◽  
Mohammad Shafee Talebianpoor ◽  
...  

Background: The present study was conducted to evaluate the effect of curcumin as a flavonoid antioxidant on serum lipid profile, oxidative stress, and blood glucose in experimental models of type 2 diabetes (DM2). Methods: Subcutaneous daily injection of dexamethasone (5 mg/kg/day) for a month was performed to induce DM2. For this purpose, 28 adult male Wistar rats were divided into four groups: healthy control group received dexamethasone carrier containing normal saline + ethanol 4% , diabetic control group took 5 mg/kg/day dexamethasone, diabetic group 1 underwent the treatment with 50 mg/kg/day curcumin, and diabetic group 2 underwent treatment with 100 mg/kg/day curcumin. Seven days after dexamethasone injection, curcumin (50 and 100 mg/kg/day) was administrated intraperitoneally for 23 days. At the end of one month, the fasting blood sugar (FBS) level was measured and recorded by glucometer. Later, after a 30-day period, the animals were anesthetized with ether and their blood samples were collected from the heart puncture to measure their serum triglyceride (TG), high density lipoprotein cholrsterol (HDL-C), low density lipoprotein cholesterol (LDL-C) and malondialdehyde (MDA). Results: The findings showed that curcumin could decrease FBS (P < 0.05), LDL-C (P < 0.01), TG (P < 0.001), and MDA (P < 0.001) and increase HDL-C (P < 0.001)  at the end of 30 days. Conclusion: These effects of curcumin can be mediated by increasing either the pancreatic secretion of insulin or releasing from insulin bonds as well as enhancing insulin receptor sensitivity. Moreover, it may prevent the glucose absorption, reduce the activity of 3-hydroxy- 3-methyl glutaryl- CoA reductase (HMG-CoA), or improve the function of liver and pancreas through potent antioxidant properties.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Servet Kavak ◽  
Lokman Ayaz ◽  
Mustafa Emre

Purpose. In this study, we tested the hypothesis that rosiglitazone (RSG) with insulin is able to quench oxidative stress initiated by high glucose through prevention of NAD(P)H oxidase activation.Methods and Materials. Male albino Wistar rats were randomly divided into an untreated control group (C), a diabetic group (D) that was treated with a single intraperitoneal injection of streptozotocin (45 mgkg−1), and rosiglitazone group that was treated with RSG twice daily by gavage and insulin once daily by subcutaneous injection (group B). HbA1c and blood glucose levels in the circulation and malondialdehyde and 3-nitrotyrosine levels in left ventricular muscle were measured.Result. Treatment of D rats with group B resulted in a time-dependent decrease in blood glucose. We found that the lipid profile and HbA1c levels in group B reached the control group D rat values at the end of the treatment period. There was an increase in 3-nitrotyrosine levels in group D compared to group C. Malondialdehyde and 3-nitrotyrosine levels were found to be decreased in group B compared to group D(P<0.05).Conclusion. Our data suggests that the treatment of diabetic rats with group B for 8 weeks may decrease the oxidative/nitrosative stress in left ventricular tissue of rats. Thus, in diabetes-related vascular diseases, group B treatment may be cardioprotective.


Author(s):  
D. G. Syahidah Nadiah Binti Abdull Majid ◽  
Mohammad Iqbal

Objective: The antihyperglycemic and antioxidative effects of L. microphyllum were evaluated by using in vivo methods in normal and alloxan induced diabetic rats.Methods: Diabetes was induced in Sprague Dawley rats by injecting alloxan through intravenous (i. v) at a dose of 100 mg/kg of body weight. Aqueous extract of L. microphyllum at different doses (400, 200 and 100 mg/kg of body weight) was administered orally (orogastric intubation) for 14 d. Blood glucose and oxidative stress markers were measured. Hematoxylin and eosin staining method were used to examine the pancreatic tissues.Results: At the 14 d interval, fasting blood glucose showed a reduction in serum glucose levels in animals pretreated with L. microphyllum compared with alloxan alone treated group. Oxidative stress was noticed in rat’s pancreatic tissue as evidenced by a significant decrease in glutathione level, glutathione reductase, glutathione-S-transferase, and catalase activities. Malondialdehyde showed a significant increase compared to the normal saline-treated control group. Serum biochemistry and oxidative stress markers were consistent with the pancreatic histopathological studies. Treatment of diabetic rats with L. microphyllum at a dose level of 100, 200 and 400 mg/kg body weight leaves extract for 14 d significantly prevented these alterations and attenuated alloxan-induced oxidative stress (P<0.05).Conclusion: The results of the present study indicated that the antihyperglycemic potential of L. microphyllum might be ascribable to its antioxidant and free radical scavenging properties. Thus, it is concluded that L. microphyllum may be helpful in the prevention of diabetic complications associated with oxidative stress.


2019 ◽  
Vol 25 (3-4) ◽  
pp. 118-126
Author(s):  
Augusta Chinyere Nsonwu-Anyanwu ◽  
Magnus Chinonye Nsonwu ◽  
Chinyere Adanna Opara Usoro

<b><i>Background:</i></b> Metabolic complications of type 2 diabetes (T2DM), including dyslipidemia, electrolyte imbalance, and oxidative stress, have been shown to be modulated by hypoglycemic agents. <b><i>Objective:</i></b> The lipid profile, electrolytes, and oxidative stress indices were evaluated in T2DM. <b><i>Methods:</i></b> Fifty T2DM patients on metformin (<i>n</i> = 23), insulin (<i>n</i> = 17), and insulin/metformin (<i>n</i> = 10) and 40 controls were studied. Fasting plasma glucose (FPG), glycated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), total antioxidant capacity (TAC), total plasma peroxide (TPP), and total calcium (Ca) values were determined colorimetrically, sodium (Na<sup>+</sup>) and potassium (K<sup>+</sup>) levels were determined by flame photometry, chloride (Cl<sup>–</sup>) and bicarbonate (HCO<sub>3</sub><sup>–</sup>) levels were determined by titration, and low-density lipoprotein cholesterol (LDL-C) levels, the atherogenic index of plasma (AIP), and the oxidative stress index (OSI) were determined by calculation. Data were analyzed using <i>t</i> test, analysis of variance, and Pearson’s correlation at <i>p</i> &#x3c; 0.05. <b><i>Results:</i></b> T2DM patients had higher lipid peroxidation (TPP and OSI), atherogenic lipids (higher LDL-C and AIP and lower HDL-C), and lower antioxidants compared to controls (<i>p</i> &#x3c; 0.05). T2DM patients with poor glycemic control had higher lipid peroxidation (higher TPP) and atherogenic lipids (TG and AIP) compared to those with good control (<i>p</i> &#x3c; 0.05). Patients with T2DM for &#x3e;5 years had higher protein glycosylation (higher HBA1c) and TC compared to those with T2DM for &#x3c;5 years (<i>p</i> &#x3c; 0.05). The class of hypoglycemic agent has no effect on the levels of all of the biochemical indices studied (<i>p</i> &#x3e; 0.05). HDL-C correlated negatively with TG (<i>r</i> = –0.347, <i>p</i> = 0.013), LDL-C (<i>r</i> = –0.322, <i>p</i> = 0.018), and AIP (<i>r</i> = –0.714, <i>p</i> = 0.000) in T2DM. <b><i>Conclusion:</i></b> Chronic T2DM and poor glycemic control are associated with reduced antioxidants, lipid peroxidation, and atherogenic dyslipidemia. Different hypoglycemic agents exert no differential effects on the metabolic indices of T2DM studied.


2011 ◽  
Vol 81 (6) ◽  
pp. 347-357 ◽  
Author(s):  
Nazıroglu ◽  
J. Butterworth ◽  
T. Sonmez

While tissue dysfunction is a well-recognized consequence of diabetes mellitus in aged people, the underlying mechanisms are poorly understood. Daily (VCE) supplementation of vitamins C and E can be beneficial to diabetic aged animals in reducing free radical production. The aim of this study was to investigate whether dietary VCE supplementation modulates oxidative stress and antioxidant redox systems in streptozotocin (STZ)-induced aged diabetic rats. Thirty aged rats (18 - 20 months) were randomly divided into three groups. The first group acted as a control and the second group was diabetic. VCE-supplemented feed was given to aged, diabetic rats, constituting the third group. Diabetes was induced using a single dose of intraperitoneal STZ. On the 21st day after STZ dosage, blood and tissue samples were taken from all animals. Glutathione peroxidase activity in liver, erythrocytes, muscle, and testes; catalase activity in plasma and erythrocytes; reduced glutathione levels in plasma; vitamin E concentration in plasma, liver, and muscle; b-carotene concentration in brain; and high-density lipoprotein (HDL)-cholesterol levels in plasma were lower in the diabetic group than in the control group. Lipid peroxidation (LP) levels in plasma, liver, brain, and muscle, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), triacyglycerols, and total and low-density lipoprotein (LDL)-cholesterol values in plasma were higher in the diabetic group than in the control group. The LP, enzyme, vitamin, and lipid profile values levels were mostly restored by VCE treatment. Liver and testis weights did not change by diabetic status and VCE supplementation, although body weight was lower in the diabetic group than in the control group. In conclusion, brain, liver, and testes tissues seem most sensitive in aged diabetic rats to oxidative stress. We observed that VCE supplementation relieves oxidative stress in the blood and tissues of diabetic aged rats by modulating the antioxidant system and lipid profile.


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