Protective effect of sun ginseng against diabetic renal damage.

The effect of sun ginseng (SG, heat-processed Panax ginseng C. A. MEYER at 120 degrees C) on diabetic renal damage was investigated using streptozotocin-induced diabetic rats. The diabetic rats showed loss of body weight gain, and increases in food and water intake and urine volume, while the oral administration of SG at a dose of 50 or 100 mg/kg body weight/d for 15 d attenuated water intake and urine excretion induced by diabetes. In addition, the diabetic rats given SG at a dose of 100 mg/kg body weight showed significant decreases in serum glucose, serum glycosylated protein and urinary protein levels, suggesting that SG improves the abnormal conditions that lead to oxidative stress. Furthermore, SG significantly reduced advanced glycation endproduct (AGE) formation and thiobarbituric acid-reactive substance levels elevated in the kidneys of diabetic rats. This implies that SG would alleviate the oxidative stress under diabetes through the inhibition of lipid peroxidation. SG also reduced the overexpression of cyclooxygenase-2 and inducible nitric oxide synthase in the kidney induced by hyperglycemia via deactivation the activation of nuclear factor-kappa B. Furthermore, treatment with SG decreased the levels of 3-nitrotyrosine, carboxymethyllysine and receptors for AGE which increase under diabetes. These findings indicate that oxidative stress is increased in the diabetic rat kidney and that SG can prevent renal damage associated with diabetes by attenuating the oxidative stress.