Normal butanol fraction ofL. flavonoids reduces inflammation caused by PCV2 infections in cell and mouse models.

Abstract

INTRODUCTION: The normal butanol fraction ofL. flavonoids (FNB) exhibits significant anti-inflammatory effects. This study investigated FNB's impact on inflammatory responses induced by Porcine circovirus type 2 (PCV2) in cell and mouse models. METHODS: An inflammatory model was established in RAW264.7 cells infected with varying PCV2 concentrations. And assigning both RAW264.7 cells and 108 SPF-grade KM mice to Control, PCV2, Rutin, and various dosages of FNB groups. Inflammatory factors such as Monocyte Chemoattractant Protein-1 (MCP-1), interleukin-6 (IL-6), IL-8, IL-10, Tumor Necrosis Factor-alpha (TNF-&#x3b1;), Reactive Oxygen Species (ROS), and Nitric Oxide (NO) were quantified using ELISA, RT-qPCR and immunohistochemistry. RESULTS: Results showed that a PCV2 titer of 10TCID/0.1 mL when applied to RAW264.7 cells effectively established aninflammatory model at 12 and 24 h post-infection. Following PCV2 infection, all the inflammatory factors displayed a significant increased both in culture supernatant and intracellular mRNA expression levels (< 0.05 or< 0.01), but these levels were reduced by FNB treatment (< 0.05 or< 0.01). In mouse sera post-PCV2 infection also showed elevated levels of IL-6, IL-8 IL-10, TNF-&#x3b1;, and MCP-1 (< 0.05 or< 0.01). Additionally, mRNA and protein levels for TNF-&#x3b1;, IL-8, IL-10, IL-6, and iNOS rose significantly in lung tissues (< 0.01) but decreased with FNB treatment (< 0.05 or< 0.01). DISCUSSION: These findings suggest that FNB reduces inflammatory factor production and modulates the inflammatory response triggered by PCV2 infection, potentially enhancing host resistance against it.