Dexmedetomidine mitigates CLP-stimulated acute lung injury via restraining the RAGE pathway

RAGE pathway plays crucial effects in causing acute lung injury (ALI). Dexmedetomidine (DEX) is showed to mitigate sepsis-stimulated ALI. However, its mechanisms have not been verified. The study was to evaluate whether the RAGE pathway participated in the actions of DEX on sepsis-stimulated ALI in rats.

Male rats were administrated with intravenously DEX 30 min after sepsis. At 24 h of sepsis, lung myeloperoxidase (MPO) and macrophages in the bronchoalveolarlavage fluid (BALF) were observed. The actions of DEX on pro-inflammatory molecules and related mechanisms were determined by immunological methods.

It was indicated that DEX markedly attenuated CLP-stimulated augment of lung inflammatory cells infiltration, along with significantly mitigated MPO activity. Besides, DEX obviously reduced lung wet/dry weight ratio and the levels of HMGB1 and RAGE in BALF and lung tissue. Moreover, DEX post-treatment apparently attenuated the histopathological lung injury compared with CLP model group. Furthermore, western blot analysis revealed that DEX efficiently restrained the activation of IκB-α, NF-κB p65, and MAPK.

Our studies demonstrated that DEX attenuates the aggravation of sepsis-stimulated ALI via down regulation of RAGE pathway, which has a potential value in the clinical therapy.