Improving Anti-Inflammatory Effect of Luteolin with Nano-Micelles in the Bacteria-Induced Lung Infection

The effective therapy for lung infectious diseases became more and more difficult since the severe antibiotic resistance of pathogenic microorganisms, it is urgent to develop new antimicrobial agents. Luteolin has been reported to play a crucial part in host immune responses. However, the clinical use of luteolin is impeded due to its hydrophobicity and low oral bioavailability. In this study, we formulated luteolin-loaded Methoxy poly(ethylene glycol)-poly(lactide) micelles (luteolin/MPEG-PLA), to improve the bioavailability of luteolin in lung infectious diseases. The results showed that luteolin/MPEG-PLA treatment could reduce the adhesion of Klebsiella pneumoniae (K. pneumoniae) to lung epithelial cells and enhance the germicidal ability of macrophages against K. pneumoniae compared to untreated group. Meanwhile, luteolin/MPEG-PLA showed stronger adhesion resistance of epithelial cells and germicidal ability of macrophages compared with free luteolin. In vivo study, luteolin/MPEG-PLA administration significantly promoted the clearance of bacteria and reduced inflammatory infiltration of lung tissue in K. pneumoniae induced lung infectious mice model. Further studies showed that treatment with luteolin/MPEG-PLA reduced the mRNA expression of LPS-induced inflammatory cytokines and chemokines in macrophages significantly. In general, luteolin/MPEG-PLA can enhance the anti-bacterial ability of lung epithelial cells and macrophages, and has a stronger therapeutic effect than free luteolin in bacterial-induced lung infection. Luteolin/MPEG-PLA may be an excellent potential drug for bacterial-induced lung infectious diseases treatment.