Ferulic acid (FA), derived from fruits and vegetables, is well-known as a potent antioxidant of scavenging free radicals. However, the role and underlying mechanism of FA on kidney ischemia reperfusion (I/R) injury are limited. Here, we explored the effects of FA on kidney I/R injury. The kidney I/R injury models were carried out by clamping bilateral pedicles for 35 min followed by reperfusion for 24 h. Mice were orally pretreated with different doses of FA for three times 24 h before I/R. The renal function was assessed by serum creatine (Scr) and blood urea nitrogen (BUN). Kidney histology was examined by hematoxylin and eosin (HE) staining and terminal deoxynucleotidly transferased UTP nick-end labeling (TUNEL) assay. Proinflammatory cytokines, caspase-3 activity, adenosine generation, adenosine signaling molecules, and hypoxia inducible factor-1 alpha (HIF-1α) were also detected, respectively. The siHIF-1α adenovirus vectors were in vivo used to inhibit the expression of HIF-1α. The results showed that FA significantly attenuated kidney damage in renal I/R-operated mice as indicated by reducing levels of Scr and BUN, ameliorating renal pathological structural changes, and tubular cells apoptosis. Moreover, FA pretreatment inhibited I/R-induced renal proinflammatory cytokines and neutrophils recruitment. Interestingly, the levels of HIF-α, CD39, and CD73 mRNA and protein as well as adenosine production were all significantly increased after FA pretreatment in the kidney of I/R-performed mice, and inhibiting HIF-α expression using siRNA abolished this protection of FA on I/R-induced acute kidney injury as evidenced by more severe renal damage and reduced adenosine production. Our findings indicated that FA protected against kidney I/R injury by reducing apoptosis, alleviating inflammation, increasing adenosine generation, and upregulating CD39 and CD73 expression, which might be mediated by HIF-1α.
Keywords: HIF-1α; adenosine; ferulic acid; renal ischemia; reperfusion injury.