Vitamin E and probucol reduce urinary lipophilic aldehydes and renal enlargement in streptozotocin-induced diabetic rats

Diabetes mellitus is characterized by complications affecting several organ s, including the kidney. Lipid peroxidation increases in diabetes and has b een implicated in the pathogenesis of diabetic complications. In this study , we examined the ability of two antioxidants, vitamin E and probucol, to r educe lipid peroxidation in vivo and renal hypertrophy, an early stage of d iabetic nephropathy, in rats. Animals were divided into four groups: non-di abetic, diabetic, diabetic treated with vitamin E, and diabetic treated wit h probucol. Animals were given antioxidants by intraperitoneal injection af ter induction of diabetes by streptozotocin injection. After 7 wk, lipid pe roxidation in vivo was measured by analyzing urinary excretion of lipophili c aldehydes and related carbonyl compounds (LACC) as 2,4-dinitrophenylhydra zones by high-performance liquid chromatography. A number of urinary lipoph ilic nonpolar and polar aldehydes and related carbonyl compounds were ident ified, almost all of which increased in diabetes. Antioxidant treatment res ulted in significantly decreased excretion of urinary LACC excretion. Antio xidant treatment of diabetic rats reduced renal hypertrophy. There was a hi gh correlation between kidney weight and urinary LACC. Since LACC are accep ted markers of lipid peroxidation, these results indicate that antioxidants can reduce the elevated lipid peroxidation of diabetes and may slow the on set of diabetic nephropathy.