Objective  To evaluate the protective effect of glycyrrhizic acid monoglucuronide (GAMG) on acute lung injury induced by single-walled carbon nanotubes (SWCNT) in mice.

  Methods  A total of 30 female C57/BL mice, aged 7-8 weeks, were randomly divided into 3 groups, namely the negative control group (normal saline 40 μg/trachea), the SWCNT model group (SWCNT 40 μg/trachea), and the GAMG treatment group (SWCNT 40 μg/trachea + GAMG 200 mg/kg). The mice in the GAMG treatment group were given GAMG intraperitoneally once a day for 3 days, while the mice in the other groups were given blank solvent at the same time. The pathological changes of lung tissue and the changes of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) in bronchoalveolar lavage fluid (BALF) were observed, the protein expression of the TLR4/MyD88/NF-κB signal pathway was detected by immunohistochemistry, and the contents of NF-κB and HSP47 were detected by immunofluorescence.

  Results  The degree of lung injury in the GAMG treatment group was obviously alleviated. Compared with the SWCNT group, the levels of MCP-1 and IL-6 in BALF, the expression of TLR4 and MyD88, and the expression of NF-κB p65 and HSP47 in lung tissue were decreased in the GAMG treatment group (P < 0.01).

  Conclusions  GAMG could significantly ameliorate SWCNT-induced acute lung injury and inhibit the activation of the TLR4/MyD88/NF-κB signal pathway in the lung.