Alogliptin repositioning confers protection against diclofenac-induced liver injury by inhibiting TLR4/NF-κB, ROS/TXNIP, and NLRP3 inflammasome-mediated pyroptosis in rats

Abstract

Drug-induced liver injury (DILI) is a significant contributor to post-marketing concerns and drug withdrawals. Diclofenac (Diclo), a nonsteroidal anti-inflammatory drug, has the potential to cause liver injury. Given the current limitations, there is a great demand for finding effective and safe preventive therapies for liver injury. Alogliptin (Alo), a dipeptidyl peptidase-4 (DPP-4) inhibitor, has multifaceted properties; however, its protective effect against Diclo-triggered liver damage remains unveiled. This study aimed to explore the hepatoprotective effect of Alo versus Diclo-evoked liver insult and decipher the underlying molecular mechanisms. Experimental rats were arbitrarily allocated into four groups: Control, Diclo, Alo 20, and Alo 40. Liver injury was evaluated microscopically, and molecular perturbations were estimated by measuring inflammatory, inflammasome, apoptotic, and oxidative stress markers. Our results showed that Alo evidently abrogated Diclo-instigated liver injury, as verified by reduced levels of ALT, AST, and LDH, along with the restoration of liver histoarchitecture. Furthermore, Alo pretreatment remarkably inhibited the perturbations in redox balance induced by Diclo, together with a reduction in inflammatory mediators and apoptotic markers. Mechanistically, Alo pretreatment effectively abated the inflammasome moieties and gasdermin D-N terminal via averting TLR4/TRAF6/NF-κB and ROS/TXNIP signaling pathways, while boosting Nrf2, ultimately curbing Diclo-induced pyroptotic cell death. This study validated the interplay among the TLR4/TRAF6/NF-κB/NLRP3/ASC/cleaved caspase-1, Nrf2/TXNIP, and ROS/TXNIP signaling trajectories in mediating Diclo-induced pyroptosis. Furthermore, it revealed that a dose-dependent hepatoprotective effect of Alo signifies its antioxidant, anti-inflammatory, anti-apoptotic, and anti-pyroptotic actions that could offer a promising strategy for alleviating Diclo-induced hepatotoxicity.

Keywords: Alogliptin; Apoptosis; Diclofenac; Inflammation; Liver injury; NLRP3 inflammasome; Pyroptosis.