Regulatory effects of polyporus polysaccharide on the expressions of cytokines released from M1 macrophages

Objective: To investigate the regulatory effects of polyporus polysaccharide (PPS) on mRNA expressions of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNOS), transforming growth factor β (TGF-β) and IL-10 in M1 macrophages.

Methods: RAW264.7 macrophages were randomly divided into five groups, negative control, M1 macrophayes, 50 μg/mL PPS, 100 μg/mL PPS, and 200 μg/mL PPS. M1 macrophages was induced by interferon γ (IFN-γ). Flow cytometry was subsequently used to examine the expressions of biomakers of M1 macrophages , such as CD16/CD32 and CD86. To observe the effects of PPS on M1 macrophages at graded levels, real-time PCR was performed to evaluate the mRNA expressions of IL-1β, IL-10, iNOS, TGF-β and TNF-α.

Results: The expressions of CD16/CD32 and CD86 in RAW264.7 macrophages significantly increased by IFN-γ, as compared with the cells without IFN-γ treatment. The mRNA levels of IL-1β, iNOS, IL-10, TGF-β and TNF-α were raised by 100 μg/mL PPS at 3, 6, 9, 12 and 24 hours (P<0.01). Moreover, the mRNA expressions of these factors could be elevated by the 6 hour-treatment of PPS at different concentrations (P<0.01).

Conclusions: M1 macrophages of can be induced from RAW264.7 cells by stimulation of IFN-γ alone. In addition, PPS can promote the mRNA expressions of IL-1β, iNOS, IL-10, TGF-β and TNF-α in M1 macrophages.