Polydatin suppresses the development of lung inflammation and fibrosis by inhibiting activation of the NACHT domain‐, leucine‐rich repeat‐, and pyd‐containing protein 3 inflammasome and the nuclear factor‐κB pathway after Mycoplasma pneumoniae infection

Abstract Mycoplasma pneumoniae (MP) can infect both the upper and lower respiratory tracts. Polydatin (PD), a traditional Chinese medicine, is known to have anti‐inflammation and antifibrosis properties. However, the protective effects of PD against MP pneumonia (MPP) remain unclear. So, the aim of this study was to describe the therapeutic effects and underlying mechanisms of PD against MPP. BALB/c mice were assigned to three groups: a normal control group, MP infection group, or PD‐treated MP infection group. BEAS‐2B cells transfected with or without NACHT domain‐, leucine‐rich repeat‐, and pyd‐containing protein 3 (NLRP3) were used to confirm the protective mechanisms of PD. Immunohistochemical analysis, Western blot analysis, enzyme‐linked immunosorbent assay, and flow cytometry were used in this study. The results showed that PD treatment suppressed MP‐induced lung injury in mice by suppressing the expression of inflammatory factors and inhibiting the development of pulmonary fibrosis. Meanwhile, PD treatment inhibited activation of the NLRP3 inflammasome and nuclear factor κB (NF‐κB) pathway. Overexpression of NLRP3 reversed the protective effect of PD against MP‐induced injury of BEAS‐2B cells. Taken together, these results indicate that PD treatment suppressed the inflammatory response and the development of pulmonary fibrosis by inhibiting the NLRP3 inflammasome and NF‐κB pathway after MP infection.