Tissue metabolomic profiling to reveal the therapeutic mechanism of reduning injection on LPS-induced acute lung injury rats

Acute lung injury (ALI) is a severe respiratory disease. To date, no medical interventions have been proven effective in improving the outcome. Reduning injection (RDN) showed a potential effect in the therapy of ALI. However, seldom does research concern the holistic pharmacological mechanisms of RDN on ALI. A metabolomic strategy, based on two consecutive extractions of the lung tissue, has been developed to investigate therapeutic mechanisms of RDN on ALI model rat. The extraction procedure was an aqueous extraction with methanol–water followed by organic extraction with dichloromethane–methanol. According to the lipophilicity of extracts, aqueous extracts were analyzed on the T3 column and organic extracts on the C18 column. Partial least-squares discriminant analysis was utilized to identify differences in metabolic profiles of rats. A total of 14 potential biomarkers in lung tissue were identified, which mainly related to phospholipid metabolism, sphingolipid metabolism, nucleotide metabolism and energy metabolism. The combined analytical method provides complementary metabolomics information for exploring the action mechanism of RDN against ALI. And the obtained results indicate metabolomics is a promising tool for understanding the holism and synergism of traditional Chinese medicine.