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Mechanisms mediating propofol protection of pulmonary epithelial cells against lipopolysaccharide‐induced cell death
Author(s) -
Gu Xiaoxia,
Lu Yan,
Chen Ji,
He Huijuan,
Li Peng,
Yang Teng,
Li Longxuan,
Liu Gang,
Chen Yanfang,
Zhang Liangqing
Publication year - 2012
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.2012.05694.x
Subject(s) - programmed cell death , apoptosis , propidium iodide , viability assay , microbiology and biotechnology , chemistry , tunel assay , lipopolysaccharide , annexin , flow cytometry , biology , biochemistry , immunology
SummaryPropofol (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 ( A 549) cells against lipopolysaccharide ( LPS )‐induced cell death and, if so, the mechanisms involved. The effects of LPS alone and in combination with propofol on A 549 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 A 549 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, Ca 2+ concentrations and reactive oxygen species ( ROS ) were analysed by immunofluorescent methods. Aconitase 2 ( ACO 2), microtubule‐associated light chain 3 ( LC 3) and beclin‐1 levels were evaluated using reverse transcription–polymerase chain reaction and/or western blot analysis. Exposure of A 549 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 A 549 cell death. This protective effect of propofol was accompanied by prevention of LPS ‐induced mitochondrial dysfunction (reductions in MMP , ACO 2 expression and ATP ) and was associated with the inhibition of LPS ‐induced activation of apoptotic signals (caspase 9 activity, ROS overproduction and Ca 2+ accumulation). In addition, propofol blocked LPS ‐induced overexpression of the autophagy‐associated proteins LC 3 and beclin‐1. The data indicate that propofol protects A 549 cells against LPS ‐induced apoptosis, and probably autophagy, by blocking LPS ‐induced activation of ROS /caspase 9 pathways and upregulation of LC 3 and beclin‐1, respectively.