Hyperbaric oxygen treatment augments the efficacy of cilazapril and simvastatin regimens in an experimental nephrotic syndrome model

Abstract

Oxidative stress plays a role in the mechanism of chronic kidney disease (CKD), and antioxidant regimes are regarded as promising treatment modalities. We compared the effects of cilazapril, simvastatin, and hyperbaric oxygen (HBO) treatment on proteinuria and on oxidative stress in adriamycine (ADR)-induced proteinuria. Seventy male Sprague-Dawley rats were housed, and 60 were injected with ADR to induce nephrosis. After the stabilization of proteinuria, rats were treated for 6 weeks with simvastatin (n = 10, 4 mg/kg/day), cilazapril (n = 10, 10 mg/kg/day), HBO (n = 10, 2.8 athmosphere absolute, 90 min/daily), HBO + cilazapril (n = 10), HBO + simvastatin (n = 10), and vehicle (n = 10). After euthanization at 12 weeks, protein carbonyl (PCO), superoxide dismutase (SOD), and glutathion peroxidase (GPx) levels were analyzed from tissues. The histological alterations in the kidneys were determined by semiquantitative scoring. Protein carbonyl (PCO) levels were higher (p < 0.001), and the GPx and SOD levels were lower (p < 0.001 for all) in the nephrotic rats. Proteinuria was correlated to PCO (r = 0.483), GPx (r = -0.686), or SOD (r = -0.620) (p < 0.001 for all). Superoxide dismutase (SOD) (beta = -0.381, p = 0.02) and GPx (beta = -0.509, p < 0.001) were independently related to proteinuria levels. Both cilazapril and simvastatin significantly improved GPx, SOD, PCO, and proteinuria. When HBO was combined with either drug, the above markers further improved (p < 0.001). Both regimens caused distinct histological features, while the combination of HBO made much significant histological improvement. Both cilazapril and simvastatin regimens improve oxidative stress and proteinuria, while the effects significantly increase with the combination of HBO treatment. HBO seems to be a candidate antioxidant strategy in glomerular diseases.