Background: Ganoderma lucidum (G. lucidum) has been used in traditional Chinese medicine for thousands of years because of its immunomodulatory properties. It is believed that G. lucidum enhances the human immune response by improving the function of human polymorphonuclear neutrophils (PMNs); nevertheless, the actual mechanism by which G. lucidum acts on human PMNs remains unknown. In this study, we investigated the molecular pathways through which G. lucidum activates human PMNs.
Methods: The phagocytic activity of PMNs was evaluated with and without treatment with the extract of sporoderm-broken germinating spores of G. lucidum. The same activity was measured after G. lucidum treatment with or without p38 mitogen-activated protein kinase (p38 MAPK) inhibitor. The activation of p38 MAPK was also evaluated with or without treatment with the extract of sporoderm-broken germinating spores of G. lucidum.
Results: In this study, we found that the extract of G. lucidum enhanced the phagocytic activity of PMNs in a dose-dependent manner, but this response was attenuated by treatment with SB203580, a p38 MAPK inhibitor. The extract of G. lucidum also enhanced activation of p38 MAPK in a dose-dependent manner.
Conclusion: These results clearly show that the extract of G. lucidum can modulate human immunity by activating human PMNs via the p38 MAPK pathway. These results may be of clinical importance to doctors of traditional Chinese medicine.