Fasudil Attenuates Concanavalin A-Induced Autoimmune Hepatitis and Is Associated with Suppression of RhoA/ROCK and TLR4/NF-κB Signaling and Modulation of Immune Responses

Background/Objectives: Autoimmune hepatitis (AIH) is a liver injury characterized by the dysregulation of immune responses. Current options for AIH have limitations that highlight the urgent need to investigate alternative or adjunct therapeutic strategies for its management. We aimed to explore the protective effects of fasudil against concanavalin A (Con A)-induced AIH in mice. Con A resulted in significant hepatic damage, evidenced by dysregulation in liver function biomarkers, marked inflammatory cell infiltration, and hepatocellular degeneration. Methods: The pretreatment of mice with fasudil (10 and 25 mg/kg, intraperitoneally) for 7 days resulted in a significant ameliorative effect on these alterations in a dose-dependent manner. Fasudil treatment was associated with suppression of the RhoA/Rho-associated coiled-coil-containing protein kinase (ROCK) pathway and concomitant downregulation of toll-like receptor 4 (TLR4)/Nuclear factor-κB (NF-κB). Results: These changes were accompanied by reduced macrophage activation and the reduction of pro-inflammatory cytokines, as evidenced by decreased nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), interferon gamma (INF-γ), and interleukin-17A (IL-17A). Moreover, it significantly limited the cluster of differentiation (CD)4+ and CD8+ T cell infiltration, thereby modulating adaptive immune amplification. Conclusions: Accordingly, fasudil restored redox homeostasis and mitigated hepatocellular death by rebalancing apoptotic regulators, normalizing the expression of B cell lymphoma 2 (BCL-2) while reducing the expression of BCL-2-associated X protein (BAX) and caspase-3 activation. Subsequently, fasudil improved liver function profiles and preserved hepatic architecture. Our results demonstrate that fasudil has potent immunomodulatory, anti-inflammatory, antioxidant, and anti-apoptotic effects in AIH. Its protective effects are associated with the suppression of RhoA/ROCK and TLR4/NF-κB signaling, supporting further investigation into the contribution of these pathways to the therapeutic actions of fasudil in AIH.