This study was conducted to investigate the immunomodulatory effect of a water-soluble polysaccharide extracted from Artemisia argyi (AAP) in vitro. The effect was assessed in peripheral blood leucocytes (PBLs) of broilers, which were incubated with different AAP concentrations (0, 25, 50, 100, and 200 μg/ml) for 24 hr at 37°C in a 5% CO2 incubator. The results showed that, compared with the control group, immunoglobulin M (IgM) concentration was increased in the supernatant of the 100 μg/ml AAP-treated group (p < .05), and immunoglobulin G (IgG) concentration was increased in the supernatant of the 200 μg/ml of AAP group (p < .05). In terms of cytokine production, production of interleukin-1beta (IL-1β), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in the supernatant was enhanced in the AAP group in a dose-dependent function, as well as enhanced mRNA expressions were showed in the cells (p < .05). The highest concentration of these three cytokines was observed in different AAP groups (IL-1β for 25 μg/ml of AAP, IL-6 for 100, and 200 μg/ml of AAP, and TNF-α for 100 μg/ml of AAP respectively). The concentration of nitric oxide (NO) was increased when using AAP at the concentration of 100 μg/ml (p < .05) as compared to the control group. No significant effects on inducible nitric oxide synthase, Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 and nuclear factor Kappa B (NF-κB) mRNA level were observed at each concentration of AAP. In conclusion, we found that AAP can specifically promote the production of immunoglobulins (IgM and IgG), cytokines (IL-1β, IL-6 and TNF-α), as well as the NO concentration in vitro, but not through the activation of the TLR4/NF-κB signalling pathway.
Keywords: Artemisia argyi polysaccharide; cytokine; immunoglobulin; nitric oxide; peripheral blood leucocyte.
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