Beyond the liver protective efficacy of silymarin; bright renoprotective effect on diabetic kidney disease

Diabetic nephropathy is one of the most important complications of diabetes mellitus (1). Recently much attention has been directed toward the use of silymarin in diabetic nephropathy (2). Silymarin possesses antioxidant and antiproteinuric effects in humans and in animal models (2,3). Silymarin seems to have two different effects in diabetic patients (2,3). Firstly control of blood sugar and secondly, silymarin seems to have the ability to ameliorate the diabetic nephropathy, an effect beyond controlling the blood glucose in diabetics (2-4). In diabetic nephropathy, excessive generation of reactive oxygen species and the overproduction of superoxide, initiate the podocyte injury, which is a major contributor to the pathogenesis of diabetic kidney disease (2-4). Various studies have shown that silymarin should be a good medication to prevent nephropathy-induced premature death in diabetic patients (2-4). Moreover, it was observed that silymarin had a good protective effect against high glucose-induced podocyte injury too (2-5). Accordingly, to find out the kidney protective properties of silymarin and deferoxamine against iron dextran-induced renal iron deposition in male rats, we also conducted an investigation. We studied rats, which were allocated to six groups and injected iron dextran intraperitoneal for a period of 4 weeks every other day, but at the beginning of the third week, they also were subjected to a 2-week (every other day) treatment with vehicle (group 2, positive control), silymarin (group 3), deferoxamine (group 4), silymarin (group 5) or combination of silymarin and deferoxamine (group 6). In this study, the levels of serum creatinine, iron, ferritin, blood urea nitrogen, and nitrite were determined and the kidneys were removed for histopathological investigations. Silymarin and deferoxamine treatments reduced the intensity of the kidney iron deposition, but only in the silymarin group a significant reduction in kidney iron deposition was observed. We concluded that silymarin is a renoprotective herb against injurious insult of iron deposition in the kidneys of animal models (6). Recently, much attention has been made on the possible kidney protective properties of metformin, too (7-9). To find out the potential efficiency of metformin to renal protection against gentamicin-induced acute renal injury and also to examine Masoud Amiri1, Parisa Motamedi2, Leila Vakili3, Nahid Dehghani4, Fereshte Kiani5, Zahra Taheri6, Sara Torkamaneh7, Parto Nasri8, Hamid Nasri8*