Effects of panax quinquefolium on streptozotocin-induced diabetic rats: role of C-peptide, nitric oxide and oxidative stress

Abstract

Background: Insulin-dependent diabetes mellitus are at high risk for vascular disorders as hypertension and nephropathy. Ginseng is one of the most widely used herbal medicines and is reported to have a wide range of therapeutic and pharmacological applications for antioxidant and vasorelaxation although the mechanism is not clear. This study, aimed to evaluate hypoglycemic, antioxidant and vasodilator effects of Panax quinquefolium aqueous ginseng extract (AGE) against streptozotocin (STZ)-induced diabetes in male rats. Furthermore explore the role of AGE in C-peptide and nitric oxide (NO) and their relation in STZ induced diabetic rats.

Methods: Thirty White male Sprague daw-ley rats weighing 150-200 gm, about 4 month old were equally divided into the following: a control group (normal, nondiabetic), a diabetic group induced by intraperitoneal (I/P) injection of STZ (non-AGE-treated) and an AGE-treated diabetic group (STZ+AGE) (for 8 days). Serum level of urea, creatinine, glucose, insulin, C-peptide and NO were analyzed. Activities of hepatic glucose-6-phosphatase (G6Pase), hepatic glycogen phosphorylase and the renal antioxidant enzyme, catalase were analyzed. Also renal oxidative stress marker malondialdehyde (MDA) was measured.

Results: Data showed that STZ treated rats produced a significant increased level of serum urea, creatinine, glucose, NO and renal MDA. Also, induced significantly higher activities of hepatic G6Pase and glycogen phosphorylase compared with controls, while give significant lowered serum insulin, C-peptide level and renal catalase activity. Whereas treatment with AGE led to a significant amelioration in the hyperglycemia (lower the activity of G6Pase and glycogen phosphorylase), hyperinsulinemia and oxidative stress markers. Besides declining the higher level of renal function test and NO.

Conclusions: STZ induced-diabetes (DM) associated with renal function disturbances, hypoinsulinemia, defective antioxidant stability and increased (NO) this may have implications for the progress of DM and its related problems. Treatment with AGE improved DM and its associated metabolic problems in different degrees. Furthermore it has insulin sensitizing, hypoglycemic, antioxidant and vasodilator effects. Communally AGE is a potential way to surmount the diabetic state and it has vasodilator effects.

Keywords: C-peptide; NO; Panax quinquefolium; diabetes; kidney function; oxidative stress.

Figure 1

Effect of AGE on serum insulin level (μIU/ml) in normal, diabetic control and diabetic+AGE groups in rats. **Values significantly different compared to normal group (P*<0.05) and high significantly different at (P**<0.01); ^aMeans not sharing the same letter are significantly different (p<0.05) compared with diabetic control. (Each group includes 10 rats); ^bAn insulin level was decreased in STZ-diabetic rats compared with normal group and treatments with AGE significantly ameliorated the produced hypoinsulinemia compared to diabetic group.

Figure 2

Effect of AGE on serum C-peptide level (ng/ml) in normal, diabetic control and diabetic+AGE groups in rat. *Values significantly different compared to normal group (P<0.05) and **high significantly different at (P<0.01). Means not sharing the same letter are significantly different (p<0.05) compared with diabetic control. (Each group includes 10 rats); ^aThe data indicated that C-peptide level reduced significantly in STZ-diabetic compared with normal rats group, while there was non significant change with AGE administration.