Ellagic Acid Ameliorates Renal Ischemic-Reperfusion Injury Through NOX4/JAK/STAT Signaling Pathway

Ellagic acid (EA), a natural polyphenolic compound, has been proved to possess multiple biological activities including alleviating ischemic-reperfusion (I/R) injury. The aim of this current study was to investigate whether EA alleviates I/R injury via regulating inflammatory signaling pathway. Rats were subjected to ischemic-reperfusion (I/R) injury and given orally with different doses of EA before surgery. H&E staining, ELISA assay, and biochemical index analysis were performed to evaluate renal injury and inflammatory factors. Oxidative stress level was detected by DCFH-DA staining and corresponding assay kits. In addition, TUNEL assay and flow cytometric assay were applied for exploring the apoptosis of tissue and cells, respectively. Western blot assay was used to assess protein expressions in tissue and cells. The results showed that EA attenuated the renal I/R injury and reserved renal cell function in vivo. The levels of TNF-a, IL-1β, IL-6, and MCP-1, oxidative stress level, and apoptosis were suppressed in EA-treated rats. Mechanistic studies showed that EA suppressed the phosphorylation of JAK1, JAK2, and STAT1 and reduced the NOX4 level. EA reduced apoptosis, hypoxia-induced inflammatory response, and ROS levels. Moreover, overexpression of NOX4 reversed the protective function with NOX4 inhibition, indicating that the effect of EA against renal IRI or cell hypoxia/reoxygenation might mainly depend on NOX4. The results suggest that EA exerts the renoprotective effect via suppressing NOX4/JAK/STAT signaling pathway, which may be a novel potential therapy for the treatment of acute kidney injury in clinic.