Sirtuin 3 deficiency aggravates contrast-induced acute kidney injury

Sirtuin 3 (Sirt3) is a key regulator of energy metabolism and oxidative stress. To investigate the role of Sirt3 in contrast-induced acute kidney injury (CIAKI), we established the model both in vivo and in vitro to explore the potential mechanisms.

In vivo, we established CIAKI models in wild-type (WT) and Sirt3-knockout (Sirt3-KO) mice. Blood urea nitrogen (BUN) and serum creatinine (Scr) were detected by enzyme-linked immunosorbent assay, Glomerular Filtration Rate (GFR) and creatinine clearance were also investigated. We detected the production of reactive oxygen species (ROS) via 2′7′-dichlorodihydro-fluorescein diacetate. The expressions of Sirt3, oxidative stress and apoptosis related markers (MnSOD, Catalase, Acetyl-MnSOD K68, Nox4, Bax, Bcl-2 and Caspase3) were measured and analyzed. In addition, we observed the effect of nicotinamide riboside (NR) on CIAKI in WT and Sirt3-KO mice. In vitro, Sirt3 was knocked out by siRNA transfection method in HK-2 cells. Sirt3, ROS, oxidative stress and apoptosis markers in HK-2 cells were also measured.

Our data demonstrated that the levels of Scr and BUN in Sirt3-KO mice were increased while the levels of the GFR and creatinine clearance were decreased in CIAKI mice. In Sirt3-KO or siRNA groups, the activities of MnSOD and Catalase were markedly down-regulated. Also, the expression of Caspase3 were markedly increased and the ratio of Bcl-2/Bax was decreased, while the ROS level was increased in Sirt3 deficiency groups. NR ameliorated CIAKI in WT mice but not in Sirt3-KO mice.

Our results suggest that Sirt3 deficiency aggravates contrast-induced acute kidney injury. Sirt3 is critical in NR-mediated renoprotection in CIAKI.