Astragalus polysaccharides alleviate LPS-induced inflammatory injury in the avian macrophage cell line HD11 via the TLR2/PI3K/AKT/NF-κB signaling pathway.

Inflammatory injury induced by bacterial components such as lipopolysaccharide (LPS) poses a major threat to poultry health, highlighting the need for effective non-antibiotic immunomodulators like Astragalus polysaccharides (APS). However, their mechanism in avian immune cells remains unclear. This study investigated the protective effects of APS against LPS-induced damage in the avian macrophage cell line HD11. Using an in vitro LPS challenge model, we found that APS pre-treatment improved cell viability, reduced cytotoxicity (LDH release), suppressed nitric oxide (NO) production, inhibited the production of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, and TNF-α), and attenuated apoptosis. Mechanistically, APS downregulated TLR2 expression, suppressed AKT phosphorylation, and blocked NF-κB p65 nuclear translocation in the LPS challenge model. Moreover, TLR2 silencing attenuated these effects, confirming the involvement of the TLR2/PI3K/AKT/NF-κB axis. These findings reveal a novel mechanism by which APS protects avian macrophages from LPS-induced inflammation and apoptosis, supporting its potential as a non-antibiotic feed additive to enhance disease resistance in poultry.