Retinoic acid attenuates contrast-induced acute kidney injury in a miniature pig model.

BACKGROUND: Contrast-induced acute kidney injury (CI-AKI) has been the third leading cause of hospital-acquired AKI. Retinoic acid (RA), the main derivative of vitamin A, has preventative and therapeutic effects in ischemia-reperfusion-AKI and UUO models, but little is known about its effects on CI-AKI. This study aimed to explore the effects of RA on CI-AKI as well as the underlying mechanisms.

METHODS: We established a new miniature pig model of CI-AKI by catheterizing the external jugular vein and injecting a single dose of iohexol after dehydration. Bun, Scr, serum and urinary RBP and β-MG levels were measured. Renal histological, TEM examination, LDH assays, TUNEL assays, GFP-LC3 plasmid transfection and western blotting were performed.

RESULTS: The levels of Bun, Scr, serum and urinary RBP and β-MG were increased after CI-AKI and decreased by RA pretreatment. The renal histology showed foamy degeneration and dilated tubules after CI-AKI, and the tissue damage was alleviated significantly by RA pretreatment. RA mitigated renal fibrosis after CI-AKI. In vitro, RA protected proximal TECs against iohexol-induced injury. RA inhibited TECs apoptosis and activated autophagy in vivo and in vitro.

CONCLUSIONS: RA alleviates CI-AKI and mitigates renal fibrosis after CI-AKI. Autophagy activation and apoptosis inhibition are involved in the protective effect of RA on CI-AKI. RA may be a new agent for the prevention and therapeutic treatment of CI-AKI in the future.