Propofol (2,6‐diisopropylphenol) is an anaesthetic agent with anti‐oxidant properties. The aim of the present study was to determine whether propofol can
protect pulmonary epithelial (A549) cells against lipopolysaccharide (LPS)‐induced cell death and, if so, the mechanisms involved. The effects of LPS alone and in combination with propofol
on A549 cell death were investigated. Cell viability was determined using the colourimetric 3‐(4,5‐dimethyl‐2 thiazoyl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) assay. Apoptotic A549
cells were detected by flow cytometry, as propidium iodide‐negative and annexin‐V‐positive cells, and terminal deoxyribonucleotidyl transferase‐mediated dUTP–digoxigenin nick end‐labelling (TUNEL).
Mitochondrial membrane potential (MMP), caspase 9 activity, Ca2+ concentrations and reactive oxygen species (ROS) were analysed by immunofluorescent methods. Aconitase 2 (ACO2), microtubule‐associated light chain
3 (LC3) and beclin‐1 levels were evaluated using reverse transcription–polymerase chain reaction and/or western blot analysis. Exposure of A549 cells to 1–50 μg/mL LPS
for 3–24 h resulted in the concentration‐ and time‐dependent induction of cell death. Cell apoptosis accounted for approximately 77% of cell death induced by LPS. Propofol (5–150 μmol/L) concentration‐dependently inhibited
LPS‐induced A549 cell death. This protective effect of propofol was accompanied by prevention of LPS‐induced mitochondrial dysfunction (reductions in MMP, ACO2 expression
and ATP) and was associated with the inhibition of LPS‐induced activation of apoptotic signals (caspase 9 activity, ROS overproduction and Ca2+ accumulation). In addition, propofol blocked LPS‐induced
overexpression of the autophagy‐associated proteins LC3 and beclin‐1. The data indicate that propofol protects A549 cells against LPS‐induced apoptosis, and probably autophagy,
by blocking LPS‐induced activation of ROS/caspase 9 pathways and upregulation of LC3 and beclin‐1, respectively.
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Document Type: Research Article
Publication date: May 1, 2012