Esculetin inhibits PRV replication by suppressing activation of the PI3K-AKT/NF-κB pathway

Pseudorabies (PR), caused by pseudorabies virus (PRV), is an acute and highly contagious disease that results in substantial economic losses to the global swine industry. In recent years, the emergence of neurotropic PRV variants capable of escaping vaccine-induced immunity has highlighted the urgent need for safe and effective antiviral agents. In this study, we demonstrated that esculetin exhibits pronounced antiviral activity against PRV both in vitro and in vivo. Esculetin inhibited PRV replication in PK-15 cells in a dose-dependent manner, with a selectivity index (SI) of 15.85 and a maximal inhibition rate of 98.53%. In vivo, administration of esculetin at 0.2 g/kg increased the survival rate of PRV-infected mice to 28.5%. Viral loads in the brain, lungs, and kidneys were reduced in a dose-dependent manner, accompanied by marked attenuation of PRV-induced tissue damage. In addition, treatment with 0.2 g/kg esculetin significantly decreased serum levels of the pro-inflammatory cytokines IL-6, TNF-α, and IL-1β. Mechanistically, esculetin inhibited AKT phosphorylation, suppressed nuclear translocation of NF-κB P65, and downregulated the expression of inflammation-related genes and proteins, including IL-6, TNF-α, iNOS, and MCP-1. Collectively, these findings indicate that esculetin may exert its anti-PRV effects, at least in part, by modulating inflammatory responses, and highlight its potential as a promising antiviral candidate for the prevention and treatment of PRV infection.