Effects of Loganin on Hepatic Inflammation and the NLRP3 Inflammasome in an Imiquimod-Induced Experimental Model

Abstract

Systemic inflammation leads to liver injury through oxidative stress and activation of innate immune pathways, including inflammasome signalling. NLRP3 inflammasome facilitates the maturation of inflammatory cytokines and amplifies inflammatory responses. Loganin (LOG), a naturally occurring iridoid glycoside, has been reported to possess anti-inflammatory and antioxidant properties; however, its effects on hepatic inflammation remain only partly understood in an imiquimod (IMQ)-induced inflammation model. This study aimed to evaluate the potential effects of LOG in the IMQ-induced systemic inflammation model, focusing on liver inflammatory changes, collagen deposition, and NLRP3/ASC- associated inflammatory responses. BALB/c mice were treated with topical IMQ to induce systemic inflammation. LOG (50 mg/kg/day, s.c.) was administered daily for seven days, and each administration was performed prior to the corresponding IMQ application. Histopathological changes were assessed using H&E and Masson’s trichrome staining. Immunohistochemistry was performed to determine NLRP3 and ASC expression in liver tissue. qPCR was used to measure the relative mRNA expression levels of Tnf and Nlrp3 in liver samples. IMQ was associated with hepatocellular alterations, increased collagen deposition, and higher immunoreactivity for NLRP3 and ASC. LOG reduced inflammatory infiltration and collagen accumulation, along with decreased expression of NLRP3 and ASC. These findings suggest that LOG administration may be associated with attenuated hepatic inflammatory alterations and changes in NLRP3/ASC-associated inflammatory responses in an IMQ-induced model of systemic inflammation.