Effects of garlic extract on serum insulin, lipid profiles and lipoprotein, cardiac functions, coronary artery structures and protein in urine in induced diabetic rats

Abstract

The objective is to study the effects of garlic extract on serum insulin, serum lipid profiles and lipoprotein including cardiac functions, coronary artery structures, and protein in urine in induced diabetic rats by a single intraperitoneal injection with the dose of 70mg/kg.BW. streptozotocin (STZ-rats). Garlic-treated STZ-rats (STZ-G) and tolbutjiamide-treated STZ-rats (STZ-T) were received daily oral feeding of 100 mg/kg.BW. garlic extract and 0.25 g/kg.BW. tolbutamide, respectively. Hypoglycemic activity and insulin effect were compared between these two groups. The results showed that at all three monitored time pointy,8116,and 20 weeks following streptozotocin injection, hypoglycemic activity of garlic extract was 74.22, 96.23 and 93.27 1 percent of activity of tolbutamide, respectively. Concomitantly, the levels of serum insulin were increased up to 37j.03, 42.16 and 62.66 percent of tolbutamide effect. Besides, the levels of serum cholesterol and triglycerides in STZ-GI rats were lower, whereas the levels of serum HDL were higher than those of STZ-rats. Moreover, garlic has been shown I to attenuate the abnormalities of cardiac functions. Systemic blood pressure was significantly decreased, while heart I rate, aortic flow rate and coronary flow rate were greater than those of STZ-rats. Left ventricular isotonic contraction values of STZ-rats were higher than those of STZ-rats at 16 and 20 weeks following streptozotocin injection. However garlic extract Could not significantly reduced proteinuria at all three monitored time points. Examination of vascular morphology by scanning and transmission electron microscopes demonstrated that the inner surface of coronary artery and arteriole of STZ-G rats were smoother than those of STZ-rats. Moreover, the thickness of arterial wall and capillary basement membrane of STZ-G rats were thinner than those of STZ-rats. The results of this study I implied that garlic could be a useful agent for preventing or delaying the diabetic cardiovascular complications.