The role of oxidative stress in streptozotocin-induced diabetic nephropathy in rats

ABSTRACT Objective The objective of this study was to evaluate the role of oxidative stress in an experimental model of streptozotocin-induced diabetic nephropathy in rats. Materials and methods Wistar, adult, male rats were used in the study. Animals were divided in the following groups: Citrate (control, citrate buffer 0.01M, pH 4.2 was administrated intravenously - i.v - in the caudal vein), Uninephrectomy+Citrate (left uninephrectomy-20 days before the study), DM (streptozotocin, 65 mg/kg, i.v, on the 20th day of the study), Uninephrectomy+DM. Physiological parameters (water and food intake, body weight, blood glucose, kidney weight, and relative kidney weight); renal function (creatinine clearance), urine albumin (immunodiffusion method); oxidative metabolites (urinary peroxides, thiobarbituric acid reactive substances, and thiols in renal tissue), and kidney histology were evaluated. Results Polyphagia, polydipsia, hyperglycemia, and reduced body weight were observed in diabetic rats. Renal function was reduced in diabetic groups (creatinine clearance, p < 0.05). Uninephrectomy potentiated urine albumin and increased kidney weight and relative kidney weight in diabetic animals (p < 0.05). Urinary peroxides and thiobarbituric acid reactive substances were increased, and the reduction in thiol levels demonstrated endogenous substrate consumption in diabetic groups (p < 0.05). The histological analysis revealed moderate lesions of diabetic nephropathy. Conclusion This study confirms lipid peroxidation and intense consumption of the antioxidant defense system in diabetic rats. The association of hyperglycemia and uninephrectomy resulted in additional renal injury, demonstrating that the model is adequate for the study of diabetic nephropathy.

Effect of Aegle marmelos (L.) Correa on alloxan induced early stage diabetic nephropathy in rats.

Diabetic nephropathy (DN) has a complex pathogenesis and poor prognosis due to the lack of therapeutic interventions. The present study investigates the effect of A. marmelos leaf extract (AME) on early alloxan induced DN. The treatment with AME was found to significantly decrease the fasting blood sugar, total cholesterol, blood urea, creatinine and renal TBARS and increased the levels of renal reduced glutathione and catalase significantly as compared to the diabetic control group. The maximum dose-dependent protection was observed at a dose of 200 mg kg-1. Histological examination revealed marked reversal of the morphological derangements with AME treatment as indicated by a decrease in glomerular expansion, tubular dilatation and inflammatory cells. The present results conclude that AME treatment has a significant ameliorative effect on early changes induced in the kidneys by alloxan and improves the outcome of DN.

Insuficiência renal aguda induzida pelo contraste em pacientes submetidos à cineangiocoronariografia: análise dos métodos de prevenção / Radiocontrast: induced nephropathy in patients undergoing coronary angiography: analysis of protective methods

A insuficiência renal aguda induzida por contraste (IRAIC) é considerada, atualmente, uma importante causa de disfunção renal em pacientes hospitalizados submetidos à cinecorioangiografia (CAG). Este achado adquire maior importância quando se verifica que a IRAIC é responsável por um aumento significativo dos índices de morbidade e mortalidade hospitalar / Radiocontrast-induced nephropathy (RIN) is considered an importante cause of renal failure in patients undergoing coronary. This data becomes more relevant when it presents a positive correlation with higher morbidity and mortality rates...

Role of metabolic control on diabetic nephropathy

OBJECTIVE: The aim of this investigation was studying the influence of glucose metabolic control on diabetic nephropathy. The authors observed the effect of acarbose, insulin, and both drugs on the metabolic control and development of mesangial enlargement of kidney glomeruli in alloxan-diabetic rats. METHODS: Five groups of Wistar rats were used: normal rats (N), non-treated alloxan-diabetic rats (D), alloxan-diabetic rats treated with acarbose (AD), alloxan-diabetic rats treated with insulin (ID), and alloxan-diabetic rats treated with insulin plus acarbose (IAD). The following parameters were evaluated: body weight; water and food intake; diuresis; blood and urine glucose levels; and the kidney lesions: mesangial enlargement and tubule cell vacuolization. Renal lesions were analysed using a semi-quantitative score 1, 3, 6, 9, and 12 months after diabetes induction. RESULTS: Diabetic rats showed a marked increase of glycemia, urinary glucose levels, diuresis, water and food intake, and weight loss, while the treated diabetic rats showed significant decreased levels of these parameters. The most satisfactory metabolic control was that of diabetic rats treated with acarbose + insulin. There was a significant mesangial enlargement in diabetic rats compared to normal rats from the third up to the 12th month after diabetes induction, with a significant difference between the animals treated with acarbose + insulin and non-treated diabetic rats. A difference between the animals treated with acarbose or insulin alone and non-treated diabetics rats was not seen. CONCLUSIONS: The authors discuss the results stressing the role of diabetic metabolic control in the prevention of diabetic nephropathy.

Changes of glomerular basement membrane components in Vacor-induced diabetic nephropathy

OBJECTIVES: The thickening of the glomerular basement membrane in rats after Vacor ingestion was examined by electron microscopy. This study was performed to elucidate which biochemical components changed in the glomerular basement membrane after Vacor-induced diabetic glomerulopathy. METHODS: Immunohistochemical analyses of type IV collagen, laminin, fibronectin and chondroitin sulfate proteoglycan were performed. A single dose of Vacor (molecular weight 272), 80 mg/kg, was administered to adult male Wistar rats by orogastric canule, and the animals were sacrificed at 0.5, 1, 3, 7, 14, 28 and 56 days after administration. RESULTS: Mild thickening of the glomerular basement membrane was evident 7 days after Vacor administration, and the width of the glomerular basement membrane was more than twice that of normal controls at 28 and 56 days. Significantly increased expressions of type IV collagen, laminin, fibronectin and neutral polysaccharide in the thickened glomerular basement membrane were noted 14 to 56 days after administration, and a mildly increased expression of chondroitin sulfate proteoglycan appeared between 3 to 7 days. CONCLUSION: These abnormally increased glomerular basement membrane components might be part of what causes diabetic nephropathy after Vacor administration.