Ganoderma lucidum Polysaccharides Reduce Lipopolysaccharide-Induced Interleukin-1 β Expression in Cultured Smooth Muscle Cells and in Thoracic Aortas in Mice

Abstract

The expression of inflammatory cytokines on vascular walls is a critical event in vascular diseases and inflammation. The aim of the present study was to examine the effects of an extract of Ganoderma lucidum (Reishi) polysaccharides (EORPs), which is effective against immunological disorders, on interleukin- (IL-) 1 β expression by human aortic smooth muscle cells (HASMCs) and the underlying mechanism. The lipopolysaccharide- (LPS-) induced IL-1 β expression was significantly reduced when HASMCs were pretreated with EORP by Western blot and immunofluorescent staining. Pretreatment with 10  μ g/mL EORP decreased LPS-induced ERK, p38, JNK, and Akt phosphorylation. But the increase in IL-1 β expression with LPS treatment was only inhibited by pretreatment with the ERK1/2 inhibitor, while the JNK and p38 inhibitors had no effect. In addition, EORP reduced the phosphorylation and nuclear translocation of nuclear factor- (NF-) κ B p65 in LPS-treated HASMCs. Furthermore, in vivo, IL-1 β expression was strongly expressed in thoracic aortas in LPS-treated mice. Oral administration of EORP decreased IL-1 β expression. The level of IL-1 β expression in LPS-treated or in LPS/EORP-treated group was very low and was similar to that of the saline-treated group in toll-like receptor 4-deficient (TLR4 ^−/−) mice. These findings suggest that EORP has the anti-inflammatory property and could prove useful in the prevention of vascular diseases and inflammatory responses.