Flavonoids from Polygonum hydropiper L. regulate PCV2-induced oxidative stress of RAW264.7 cells via Pi3k/AKT and Nrf2/HO-1 signaling pathways.

Flavonoid n-butanol (FNB) possess diverse pharmacological properties. This study aimed to explore the mechanism of FNB in regulating oxidative response in PCV2-infected RAW264.7 cells. PCV2-infected macrophages were treated with FNB, and oxidative stress markers, antioxidant enzyme activities, as well as related gene and protein expression were assessed to evaluate FNB's regulatory effects. Specifically, the level of Nitric Oxide (NO), Total antioxidant capacity (T-AOC), anti-hydroxyl radical capacity, anti-superoxide anion capacity, L-Glutathione (GSH) level, Super Oxide Dismutase (SOD) and Catalase (CAT) were detected. The expression of key oxidative stress-related and signaling pathway genes and proteins was determined by qPCR and western blotting, respectively. The results indicated that FNB reduced intracellular ROS, increased SOD and CAT activities, improved antioxidant capacity, upregulated the mRNA expression levels of HO-1, NQO1, Nrf2, Pi3kca, SOD, and HDAC1, downregulated AKT, Keap1, and HAT1, enhanced HDAC1 activity, and inhibited HAT activity. In conclusion, FNB protects against PCV2-induced oxidative damage by activating the PI3K/AKT pathway and inhibiting Keap1, which collectively enhance the Nrf2/HO-1 antioxidant response.