Oxidative stress in 5/6 nephrectomized rat model: effect of alpha-lipoic acid.

Alpha-lipoic acid (ALA) is a powerful antioxidant, and its effect in ameliorating complications of diabetes mellitus has been widely documented. The aim of this study was to investigate the role of ALA in the disease progression of remnant kidneys (RK). Systolic blood pressure (SBp), hemoglobin, renal function, kidney malondialdehyde (MDA), glutathione (GSH), vitamin E (Vit E) concentrations, p65 nuclear factor (NF)-κB activity, and macrophage infiltration were analyzed in sham and RK rats supplemented with ALA (100 mg/kg body weight, i.p., every other day) or vehicle for 12 weeks. RK rats exhibited increases in SBp, kidney MDA concentration, p65 NF-κB activity, and macrophage infiltration, which were prominent in weeks 4 and 8 and decreased at week 12. RK rats also showed anemia, microalbuminuria, and decreased renal function and kidney GSH and Vit E concentrations. These changes were all attenuated by 8 weeks of ALA treatment compared to RK vehicle group. But the continued ALA treatment after week 8 reversed the beneficial effect on SBp, kidney MDA concentration, p65 NF-κB activity, macrophage infiltration, anemia, microalbuminuria, and renal function, while the beneficial effect was maintained if the treatment was discontinued after week 8. Furthermore, ALA increased albuminuria and kidney MDA concentration in sham animals. In conclusion, ALA administration attenuates oxidative stress, inflammation, and hypertension and delayed the deterioration of kidney function in RK rats with enhanced oxidative stress, while in healthy animals or RK rats with a well-balanced redox state, ALA may act as a pro-oxidant, contributing to renal dysfunction.