Supplementation of conventional anti-diabetic therapy with alpha-lipoic acid prevents early development and progression of diabetic nephropathy

Background: Diabetic nephropathy (DN) is the leading cause of end-stage renal disease. Current pharmacological interventions only retard DN progression. Alpha-lipoic acid (ALA) is a potent antioxidant with beneficial effect in other diabetic complications. This study investigates whether ALA supplementation prevents early development and progression of DN. Method: Fifty-eight male Sprague-Dawley rats were randomly assigned to healthy control and diabetic groups and subjected to overnight fasting. Type 2 diabetes mellitus (T2DM) was induced in diabetic group by intraperitoneal administration of nicotinamide (110 mg/kg) and streptozotocin (55 mg/kg). On day 3 after T2DM induction, diabetic rats received oral daily administration of ALA (60 mg/kg), gliclazide (15 mg/kg), ramipril (10 mg/kg) or drug combinations for 6 weeks. Untreated diabetic rats served as diabetic control. Blood, kidneys and pancreas were harvested for biochemical and histological analyses. Result: Induction of T2DM resulted in hypoinsulinemia, hyperglycemia and renal pathology. ALA supplementation maintained β-cell function, normoinsulinemia and normoglycemia in diabetic rats, and prevented renal pathology (PAS, KIM-1, plasma creatinine, total protein, blood urea nitrogen, uric acid and urine albumin/creatinine ratio) and triglycerides level compared to diabetic control (p < 0.001). Additionally, ALA supplementation significantly prevented elevated serum and tissue malondialdehyde, collagen deposition, α-SMA expression, apoptosis and serum IL-1β and IL-6 levels while it markedly increased renal glutathione content and plasma HDL-C compared to diabetic control group (p < 0.001). Conclusion: ALA supplementation prevents early development and progression of DN by exerting anti-hyperglycemic, antioxidant, anti-inflammatory, anti-fibrotic and anti-apoptotic effects. Our findings provide additional option for clinical treatment of DN in T2DM patients.