Effects of Sophora subprostrate polysaccharide on proliferation activity and inflammation-related factors of immune cells infected with porcine circovirusⅡ(PCV2)

【Objective】This study aimed to investigate the proliferation activity and inflammation-related factors of Sophora subprostrate polysaccharide(SSP) on porcine circovirusⅡ(PCV2) infected RAW264.7 cells, and to reveal its regulation on PCV2 infected immune cells inflammation-related factors.【Method】Established the inflammatory model of PCV2 infected RAW264.7 cells in vitro, and then cultured with different concentrations(25, 50, 100, 200, 400, 800 and 1600μg/mL) of SSP.CCK-8 method was used to determine the proliferation activity of RAW264.7 cells and PCV2 infected RAW264.7 cells with SSP at different concentrations.The effect of SSP at different concentrations on inflammationrelated factors(IL-1β, IL-8, MCP-1 and COX-1) in PCV2 infected RAW264.7 cells were determined by enzyme linked immunosorbent assay(ELISA).【Result】Compared with the cell control group, the results showed that the concentration of SSP ≤ 400μg/mL had no significant effect on RAW264.7 cell viability(P> 0.05), but SSP concentrations at 800μg/mL and 1600μg/mL extremely significantly decreased the viability of RAW264.7 cells(P< 0.01, the same below).After PCV2 infection, the proliferation activity of RAW264.7 cells was extremely decreased, the secretion levels of inflammatory cytokines IL-1β, IL-8 and MCP-1 and the activity of intracellular COX-1 were extremely increased.100-400μg/mL of SSP exttemely increased the viability of PCV2 infected RAW264.7 cells, and the secretion levels of IL-1β, IL-8, MCP-1 and the activity of COX-1 in RAW264.7 cells were decreased compared to PCV2 group.Compared with PCV2 model group, 100μg/mL of SSP significantly decreased IL-1βand MCP-1 secretion levels in PCV2 infected RAW264.7 cells(P< 0.05, the same below);200μg/mL of SSP extremely decreased the secretion level of MCP-1, significantly decreased the secretion levels of IL-1βand IL-8, and the activity of COX-1 in PCV2 infected RAW264.7 cells;SSP at 400μg/mL of could extremely reduce the levels of IL-1β, IL-8 and MCP-1 and the activity of COX-1 in PCV2 infected RAW264.7 cells.【Conclusion】SSP has no significant effect on the proliferation activity of RAW264.7 cells, and shows no cytotoxicity.100-400μg/mL of SSP extremely increases the proliferation activity of PCV2 infected RAW264.7 cells, and play an anti-inflammatory effect via regulating the secretion levels of inflammation-related factors.