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El-Shemi AG, Kensara OA, Alsaegh A, Mukhtar MH. Pharmacotherapy with Thymoquinone Improved Pancreatic β-Cell Integrity and Functional Activity, Enhanced Islets Revascularization, and Alleviated Metabolic and Hepato-Renal Disturbances in Streptozotocin-Induced Diabetes in Rats. Pharmacology 2017; 101:9-21. [DOI: 10.1159/000480018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 07/31/2017] [Indexed: 12/20/2022]
Abstract
Aims: This study is aimed at evaluating the antidiabetic effects of thymoquinone (TQ) on streptozotocin (STZ)-induced diabetes in rats, and exploring the possible underlying mechanisms. Methods: Diabetes was induced in adult male Wistar rats by intraperitoneal injection of freshly prepared STZ (65 mg/kg). After disease induction, 42 rats were equally assigned to: controls, STZ-diabetic group, and STZ-diabetic group treated with oral TQ (35 mg/kg/day) for 5 weeks. Fasting blood glucose levels were determined weekly, and the animals were euthanized at day 38 post-STZ injection. Blood samples were assessed for glucose-insulin homeostasis parameters (plasma glucose, glycated hemoglobin, serum insulin, homeostatic model assessment of insulin resistance, and insulin sensitivity index) and lipid profile. Resected pancreases were subjected to histological examination and immunohistochemical or enzyme-linked immunosorbent assay assessment to determine the pancreatic expression of insulin sensitizing β-cells, anti-apoptotic protein “survivin,” apoptosis-inducer “caspase-3,” prototypic angiogenic factors (vascular endothelial growth factor [VEGF] and endothelial cluster of differentiation 31 [CD31]), pro- and anti-inflammatory cytokines (interleukin-1beta [IL-1β] and interleukin-10 [IL-10], respectively), thiobarbituric acid reactive substances (TBARS), total glutathione (GSH), and superoxide dismutase (SOD). The hepato-renal statuses were assessed biochemically and histologically. Results: Therapy with TQ markedly improved the integrity of pancreatic islets, glucose-insulin homeostasis-related parameters, lipid profile parameters, and hepato-renal functional and histomorphological statuses that collectively were severely deteriorated in untreated diabetic group. Mechanistically, TQ therapy efficiently increased insulin producing β-cells, upregulated survivin, VEGF, CD31, IL-10, GSH and SOD, and downregulated caspase-3, IL-1β, and TBARSs in the pancreatic tissues of STZ-diabetic rats. Conclusions: These findings prove the anti-diabetic potential of TQ and its efficacy in regenerating pancreatic β-cells and ameliorating pancreatic inflammation and oxidative stress, and highlight its novelty in repressing apoptosis of β-cells and enhancing islet revascularization in STZ-diabetic rats. Further studies are required to support these findings and realize their possible clinical significance.
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Yao Y, Wang W, Li M, Ren H, Chen C, Wang J, Wang WE, Yang J, Zeng C. Curcumin Exerts its Anti-hypertensive Effect by Down-regulating the AT1 Receptor in Vascular Smooth Muscle Cells. Sci Rep 2016; 6:25579. [PMID: 27146402 PMCID: PMC4857140 DOI: 10.1038/srep25579] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/18/2016] [Indexed: 01/11/2023] Open
Abstract
Curcumin exerts beneficial effects on cardiovascular diseases, including hypertension. However, its mechanisms are unknown. We propose that curcumin prevents the development of hypertension by regulating AT1 receptor (AT1R) expression in arteries. The present study examined how curcumin regulates AT1R expression in vascular smooth muscle cells and investigated the physiological significance of this regulation in angiotensin (Ang) II-induced hypertension. The results showed that curcumin decreased AT1R expression in a concentration- and time-dependent manner in vascular smooth muscle cells. Using luciferase reporters with an entire AT1 or a mutant AT1R in A10 cells, the AT1R promoter activity was inhibited by 10−6 M curcumin, and the proximal element (from −61 to +25 bp) of the AT1R promoter was crucial for curcumin-induced AT1R down-regulation. An electrophoretic mobility shift assay showed that curcumin decreased specificity protein 1 (SP1) binding with the AT1R promoter in A10 cells. Curcumin treatment reduced Ang II-induced hypertension in C57Bl/6J mice, which was accompanied by lower AT1R expression in the arteries and decreased Ang II-mediated vasoconstriction in the mesenteric artery. These findings indicate that curcumin down-regulates AT1R expression in A10 cells by affecting SP1/AT1R DNA binding, thus reducing AT1R-mediated vasoconstriction and subsequently prevents the development of hypertension in an Ang II-induced hypertensive model.
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Affiliation(s)
- Yonggang Yao
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Wei Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Meixiang Li
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Hongmei Ren
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Caiyu Chen
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Jialiang Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Wei Eric Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
| | - Jian Yang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China.,Department of Nutrition, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, P. R. China.,Chongqing Institute of Cardiology, Chongqing, P. R. China
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Molecular mechanisms of curcumin on diabetes-induced endothelial dysfunctions: Txnip, ICAM-1, and NOX2 expressions. BIOMED RESEARCH INTERNATIONAL 2014; 2014:161346. [PMID: 25054130 PMCID: PMC4098609 DOI: 10.1155/2014/161346] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Revised: 06/04/2014] [Accepted: 06/08/2014] [Indexed: 12/20/2022]
Abstract
We aim to investigate the effects of curcumin on preventing diabetes-induced vascular inflammation in association with its actions on Txnip, ICAM-1, and NOX2 enzyme expressions. Male Wistar rats were divided into four groups: control (CON), diabetic (DM; streptozotocin (STZ), i.v. 55 mg/kg BW), control-treated with curcumin (CONCUR; 300 mg/kg BW), and diabetes treated with curcumin (DMCUR; 300 mg/kg BW). 12th week after STZ injection, iris blood perfusion, leukocyte adhesion, Txnip, p47phox, and malondialdehyde (MDA) levels were determined by using laser Doppler, intravital fluorescent confocal microscopy, Western Blot analysis, and TBAR assay, respectively. The iris blood perfusion of DM and DMCUR was decreased significantly compared to CON and CONCUR (P < 0.001). Plasma glucose and HbA1c of DM and DMCUR were increased significantly compared to CON and CONCUR (P < 0.001). Leukocyte adhesion, ICAM-1, p47phox expression, and MDA levels in DM were increased significantly compared to CON, CONCUR, and DMCUR (P < 0.05). Txnip expression in DM and DMCUR was significantly higher than CON and CONCUR (P < 0.05). From Pearson's analysis, the correlation between the plasma MDA level and the endothelial functions was significant. It suggested that curcumin could ameliorate diabetic vascular inflammation by decreasing ROS overproduction, reducing leukocyte-endothelium interaction, and inhibiting ICAM-1 and NOX2 expression.
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Curcumin and diabetes: a systematic review. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2013; 2013:636053. [PMID: 24348712 PMCID: PMC3857752 DOI: 10.1155/2013/636053] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 08/30/2013] [Accepted: 09/12/2013] [Indexed: 12/20/2022]
Abstract
Turmeric (Curcuma longa), a rhizomatous herbaceous perennial plant of the ginger family, has been used for the treatment of diabetes in Ayurvedic and traditional Chinese medicine. The active component of turmeric, curcumin, has caught attention as a potential treatment for diabetes and its complications primarily because it is a relatively safe and inexpensive drug that reduces glycemia and hyperlipidemia in rodent models of diabetes. Here, we review the recent literature on the applications of curcumin for glycemia and diabetes-related liver disorders, adipocyte dysfunction, neuropathy, nephropathy, vascular diseases, pancreatic disorders, and other complications, and we also discuss its antioxidant and anti-inflammatory properties. The applications of additional curcuminoid compounds for diabetes prevention and treatment are also included in this paper. Finally, we mention the approaches that are currently being sought to generate a "super curcumin" through improvement of the bioavailability to bring this promising natural product to the forefront of diabetes therapeutics.
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