Our previous study found that Lianhuaqingwen reduces lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice by suppressing p53-mediated apoptosis. To identify the type of lung cells affected by Lianhuaqingwen, we conducted a cell experiment.
METHODS: C57/B6 mice and A549 cells were administered Lianhuaqingwen and LPS. A549 cells were transfected with p53 siRNA to inhibit p53. The degree of ALI in mice was validated by haematoxylin and eosin staining as well as measurement of IL-1β and MCP-1 levels.
In A549 cells, Cell Counting Kit-8 (CCK-8), DHE and TUNEL assays were used to assess cell viability, reactive oxygen species (ROS) production and apoptosis, respectively. Western blot analysis was used to evaluate the protein expression of p53, Bcl-2, Bax, caspase-9 and caspase-3. Co-immunofluorescence was used to detect cytochrome C distribution.
KEY FINDINGS: Lianhuaqingwen alleviated LPS-induced ALI in vivo. Lianhuaqingwen at 300 μg/ml increased cell viability, lowered ROS production and reduced apoptotic cells in vitro. Lianhuaqingwen enhanced Bcl-2 expression and reduced Bax, caspase-9 and caspase-3 expression as well as blocked cytochrome C release under LPS stimulation. Treatment with a combination of Lianhuaqingwen and p53 siRNA was more effective than treatment with Lianhuaqingwen alone.
CONCLUSION: Lianhuaqingwen inhibits p53-mediated apoptosis in alveolar epithelial cells, thereby preventing LPS-induced ALI.