Abstract
Ochratoxin A (OTA), a common mycotoxin contaminant, poses significant health risks through its multi-organ toxicity. While OTA is known to cause immune organ dysfunction leading to immunotoxicity, its precise mechanistic pathways remain unclear. The spleen is an important immune organ of the body and plays a key role in immune defense and homeostasis maintenance. Astaxanthin (AST), a potent antioxidant with demonstrated immunomodulatory properties, exhibits a broad therapeutic potential including anti-inflammatory, wound-healing, anti-aging, and hepatoprotective effects. Therefore, this study aimed to explore the mechanism by which AST attenuates OTA-induced immunotoxicity using a chicken OTA/AST treatment model. Sixty 1-day-old, white-feathered, sex-undifferentiated chicks were randomly allocated into four groups (n = 15): (1) Control, (2) OTA (1 mg/kg), (3) AST (100 mg/kg), and (4) OTA + AST (1 mg/kg OTA + 100 mg/kg AST). The experiment lasted for 21 days to establish the model. Subsequently, serum ELISA, antioxidant capacity assays, qRT-PCR, and western blot (WB) analyses were employed to explore the protective role of AST against immunotoxicity. The results showed that AST increased splenic organ coefficients and serum immunoglobulin (IgM and IgG) concentrations (p < 0.01) and decreased the expression of inflammatory factors (IL-8, IL-6, and IL-1β) (p < 0.01). We found that OTA was involved in the expression of the PTEN/PI3K/AKT signaling pathway (PTEN, PI3K, AKT, p-AKT (Ser473)) and apoptotic genes (Bcl-2, Bax, Caspase3, Caspase9). Notably, AST significantly attenuated OTA-induced oxidative damage (ROS, MDA, T-AOC) in the spleen (p < 0.05), upregulated the expression of PI3K and p-AKT (Ser473) (p < 0.05) and inhibited the expression of PTEN and apoptosis-related genes (p < 0.05). In summary, AST attenuates OTA-induced immunotoxicity by alleviating oxidative stress and modulating the PTEN/PI3K/AKT signaling pathway.