Exploring the Mechanism of Bu Zhong Yi Qi Decoction in Treating Sepsis-induced Acute Lung Injury based on Network Pharmacology and Experimental Verification.

Introduction: Sepsis-induced acute lung injury (S-ALI) is one of the diseases with a very high fatality rate. However, the traditional Chinese medicine compound Buzhong Yiqi Decoction (BZYQD) has an excellent effect in the treatment of S-ALI. Nevertheless, its mechanism of action is still unclear. In this study, we explored the molecular mechanisms of S-ALI injury treated with buzhong yiqi decoction through network pharmacology, in combination with in vivo experimental validation.

Methods: Traditional Chinese medicine system pharmacology (TCMSP) database was used to screen the chemical composition of BZYQD and its action targets; Multiple databases were used to collect target genes for-S-ALI, including OMIM, TTD, GeneCards, and DrugBank; The STRING database was used for the protein- protein interaction (PPI) analysis of the common targets of the BZYQD and the S-ALI; The DAVID database was used for GO and KEGG analysis; molecular docking was used to detect the binding capacity of core components and targets. HE staining was used to visualize the pathology of lung tissue in each group; ELISA was used to detect the levels of inflammatory factors (IL-1β, IL-6, IL-8, NF-κB and TNF-α) and oxidative stressrelated factors (LDH, CK-MB, SOD, GSH-Px); The qPCR and Western blot were used to examine the mRNA and protein expression of IL-1β, IL-6, TNF-α NF-κB, p-NF-κB, PI3K, p-PI3K, AKT, and IKKα.

Results: 113 chemical components and 226 targets were screened from BZYQD; 9059 S-ALI-related genes were screened out, with a total of 228 intersecting targets between BZYQD and S-ALI. Stigmasterol, quercetin, and isorhamnetin are the core components of BZYQD, PPI analysis shows that AKT1, IL6, TNF, and IL1B are the core targets of BZYQD for treating S-ALI, and molecular docking results show that the core components have high binding activity with the target; Enrichment analysis shows that these core targets are related to the TNF signaling pathway. In vivo experimental studies have found that BZYQD can improve the degree of inflammatory infiltration and edema in lung tissue of S-ALI model mice, reduce the expression of IL-6, IL-1β, IL-8, TNF-α, LDH, CK-MB, and NF-κB in serum (P<0.05), as well as the mRNA and protein expression of IL-6, IL-1β, TNF-α, NF-κB, p-NF-κB, PI3K, p-PI3K, AKT, and IKKα in lung tissue (P<0.05), and levels of SOD and GSH-Px were increased (P<0.05).

Discussion: The action targets of the main chemical components of BZYQD are TNF, AKT, and IL6. These targets can promote the activation of PI3K and TNF pathways and mediate the occurrence of inflammation and oxidative stress, which provides inspiration for the treatment of S-ALI. However, the results of this study still need to be verified in combination with in vitro approaches.

Conclusion: This study suggests that the mechanism of BZYQD in treating S-ALI may be achieved by inhibiting the TNF and PI3K signaling pathway and reducing inflammation and oxidative stress levels.