الفهرس 
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Abstract
The present study investigated the potential protective effect of EGCG on type 2 diabetes-induced heart injury. A rat model of diabetes was achieved by intraperitoneal (i.p.) injection of nicotinamide (100 mg/kg), 20 min before the administration of streptozotocin (55 mg/kg, i.p.). After confirmation of diabetes, EGCG (2 mg/kg, p.o.) was administrated on alternate days for one month. Treatment of diabetic rats with EGCG showed a remarkable reduction in glucose, glycosylated hemoglobin (HbA1c), insulin resistance index (HOMA-IR) and lipid profile levels with an elevation in insulin levels, indicating its antihyperglycemic and antidyslipidemic actions. EGCG treatment also suppressed the increase in the levels of superoxide anion, 4-hydroxynonenal (4-HNE) and protein carbonyl, whereas it increased the content of glutathione (GSH) and the activities of superoxide dismutase (SOD) and catalase (CAT) in heart of diabetic rats, indicating its antioxidant capacity. In addition, EGCG improved heart function of diabetic rats as evidenced by a remarkable reduction in troponin T (cTnT) level and creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) and aspartate aminotransferase (AST) activities in the serum. Oral administration of EGCG for one month after diabetes induction significantly protected the increase in serum levels of pro-inflammatory cytokines, including interleukin-1 beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α), and adhesion molecules, including intracellular adhesion molecules-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), suggesting its anti-inflammatory potential. Furthermore, EGCG hampered the mitochondrial apoptotic pathway through increasing anti-apoptotic protein Bcl-2 level and decreasing pro-apoptotic proteins p53, Bax, cytochrome c (cyto c) and caspase-3 and 9 levels in heart of diabetic rats, indicating its anti-apoptotic action. Diabetic rats treated with EGCG also exhibited decreased level of DNA damage in the myocardium. The histological examinations indicated the cardioprotective effect of EGCG against harmful impact of diabetes. In conclusion, these findings strongly suggest that EGCG has a protective effect on the heart affected by type 2 diabetes through modulating the cardiometabolic risk factors, oxidative stress, inflammation, cell death and fibrosis. Therefore, these beneficial effects coupled with the excellent safety and tolerability profile of EGCG suggest that it can be recommended as a complementary supplement for diabetic patients after well exploration in human trials.