Dietary omega-3 alleviates copper-induced nephrotoxicity via suppression of NLRP3-mediated pyroptosis and lipid metabolism disorder in chickens

Abstract

Excessive use of copper (Cu) in poultry farming induces nephrotoxicity closely related to inflammatory response and lipid metabolism disorder, but the mechanism remains unclear. Omega-3 (Ω-3), a natural polyunsaturated fatty acid with anti-inflammatory and antioxidative stress properties, has been demonstrated to exert protective effects on the kidneys. However, whether Ω-3 can alleviate Cu-induced renal injury and the underlying mechanisms remain unclear. Therefore, we investigated the effects of Cu exposure on chicken kidney tissues and CEK cells in this study. Subsequent dietary supplementation with Ω-3 was administered to evaluate its ameliorative effects on Cu-induced renal injury. Cu exposure significantly disrupted mitochondrial homeostasis. This was evidenced by downregulated mRNA levels of OPA1 and MFN1/2, reduced ATP content, tricarboxylic acid (TCA) cycle dysfunction, mitochondrial membrane depolarization, and excessive ROS accumulation. Electron microscopy confirmed that Cu exposure induced pyroptosis in renal cells, accompanied by activation of the NF-κB-NLRP3-GSDMD pathway, leading to significantly upregulated expression of IL-1β, IL-18, Caspase-1, ASC, and GSDMD. Additionally, Cu exposure disrupted lipid metabolism by upregulating PPARγ, SREBP1, and Fas while downregulating PGC-1α, as evidenced by abnormal lipid droplet accumulation observed under electron microscopy. Furthermore, Cu exposure significantly inhibited the Wnt3a/β-catenin signaling pathway, impairing renal repair functions. Notably, the administration of Ω-3 effectively alleviated these adverse effects. This study reveals that Ω-3 exerts its protective effects against Cu-induced nephrotoxicity by modulating the NF-κB-NLRP3-GSDMD axis, the Wnt/β-catenin signaling pathway, and lipid metabolism for the first time. This provides a dietary strategy to enhance poultry health in intensive farming.