Renal lesions in streptozotocin-induced diabetic rats maintained on onion and capsaicin containing diets

Onion (Allium cepa) powder and capsaicin, the pungent principle of red pepp er (Capsicum annum) were added in the amounts of 3 g% and 15 mg%, respectiv ely. to the diet of streptozotocin-induced diabetic Wistar rats for 8 weeks . The presence of renal lesions was assessed by the extent and quality of p roteinuria and by the leaching of renal tubular enzymes into the urine. Ren al integrity was assessed by measuring the activities in the kidney tissue of several key enzymes of carbohydrate metabolism and of polyol pathway, tr ansaminases, and ATPases. Data on enzymuria and proteinuria, activities of kidney ATPases present in diabetic patients, suggested that dietary onion c aused significant beneficial modulation of the progression of renal lesions in the diabetic rats. These findings were also corroborated by histologic examination of kidney sections. Dietary capsaicin did not have any favorabl e influence on renal pathology in diabetes. It is inferred that this benefi cial ameliorating influence of dietary onion on diabetic nephropathy may be mediated through onion's ability to lower blood cholesterol levels and to reduce lipid peroxidation. (C) Elsevier Science Inc. 1999. All rights reser ved.