Alteration of oxidative stress and inflammatory cytokines induces apoptosis in diabetic nephropathy

Abstract

Diabetic nephropathy (DN) is one of the most significant long-term complications in terms of morbidity and mortality for diabetic patients; however, the exact cause remains unknown. To address this, the DN model was established, and oxidative stress indexes, including malondi-aldehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and inflammatory cytokines, includin-ginterleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta (TGF-β), were examined by ELISA. Renal pathological alterations and cell apoptosis was examined by hematoxylin and eosin and terminal deoxy-nucleotidyl transferase mediated dUTP nick-end labeling staining, respectively. The expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-2 associated X (Bax) and caspase-3 wereexamined by immunohistochemistry and western blotting. The DN model was correctly established, with lower body weight and the higher blood glucose in the diabetes model group. The expression levels of SOD and GSH-Px were significantly decreased in the diabetes model group; however, MDA, IL-6, TNF-α and TGF-β were significantly increased. The kidney was severely damaged in the diabetes model group, with inflammatory cell invasion, increasing amount of interstitial matrix and hypertrophy with vacuolar degeneration of renal tubular cells. Cell apoptosis levels were significantly increased, and Bcl-2 was significantly decreased in the diabetes model group in contrast with that of the sham group; however, Bax and caspase-3 were significantly increased. It suggested that increased oxidative stress and inflammatory cytokines may enhance the apoptosis levels in DN, and may provide a significant diagnostic reference for DN in diabetes patients.