Down-regulation of TNF-α/RIPK/Caspase-8 axis by combined infliximab and umbelliferone prevents unilateral ureter ligation-induced interstitial renal fibrosis

Obstructive nephropathy is a chronic condition that causes progressive kidney damage due to inflammation, oxidative stress, necroptosis, and fibrosis. The present study aimed to evaluate the potential chemopreventive effect of infliximab (TNF-α inhibitor) or umbelliferone (UMB, a natural antioxidant) individually and together to treat unilateral ureter ligation (UUL)-induced interstitial renal fibrosis in rats. The therapeutic effects were assessed through renal function biomarkers, histopathology, fibrosis, inflammation, oxidative stress, and necroptosis. UUL-induced renal injury led to increased serum biomarkers (urea, creatinine, uric acid), inflammation markers (TNF-α, NF-κB, IKK), oxidative stress (elevated NADPH oxidase and MDA, reduced Nrf2/HO-1, GSH, SOD), and necroptosis (upregulated RIPK1/RIPK3/p-RIPK3/MLKL/caspase-8), with substantial collagen deposition and fibrosis. Treatment with infliximab and UMB showed preventive effects by suppressing TNF-α signaling, reducing oxidative stress, and boosting antioxidant defense. Combined therapy provided superior results by downregulating TNF-α/RIPK/Caspase-8 pathways, enhancing Nrf2/HO-1 activity, reducing fibrosis, and restoring renal structure and function. Computational docking confirmed the ability of UMB to interact with TNF-α and RIPK3/MLKL binding sites. In conclusion, the combination of infliximab and UMB offers a promising multi-targeted approach to treat obstructive nephropathy and related chronic kidney diseases and highlights its potential to modulate key pathways involved in kidney fibrosis.