Effects of chronic ethanol drinking on the blood brain barrier and ensuing neuronal toxicity in alcohol-preferring rats subjected to intraperitoneal LPS injection.
OBJECTIVE
Although alcohol drinking impairs the blood-brain barrier (BBB), the underlying mechanism is not fully understood. Thus, the effects of chronic ethanol drinking on the BBB were studied in vivo.


METHODS
Alcohol-preferring rats were given for 70 days free choice water and 15% ethanol. Then, they received LPS by i.p. injection. Efflux of [(14)C]sucrose or [(14)C]dextran was measured by their microinjection into the brain. Endothelial cells and neurons were isolated from the brain and analysed for mitogen-activated protein kinase (MAPK) and the tight-junction (TJ) protein phosphorylation, NFkappaB activation, mRNA levels of TJ proteins, inducible nitric oxide synthase, tumour necrosis factor alpha, interleukin-1 beta (IL-1beta), IL-10, CASPASE-8, and DNA damage.


RESULTS
LPS transiently increased [(14)C]sucrose efflux in water drinking, while it caused a lasting increase in [(14)C]sucrose and [(14)C]dextran efflux in ethanol-drinking rats. The time-course of changes in the TJ correlated with (i) an increase in extracellular signal-regulated kinase (ERK), p38(mapk) Jun-N-terminal Kinase (JNK), and TJ protein phosphorylation, (ii) RelA-p50 and p50-p50 activation, and (iii) a decrease in the TJ proteins' mRNA levels in endothelial cells and neurons. Apoptotic cells were detected in water drinking and LPS (WC-LPS) neurons at 24 h after LPS exposure. Neurons from Et-LPS rats did not exhibit apoptosis.


CONCLUSIONS
LPS injection in WC-LPS rats transiently disrupted the BBB. Lack of JNK activation and CASPASE-8 may be responsible for lack of apoptosis in endothelial cells and vice versa in neurons. Chronic alcohol drinking in ethanol drinking and LPS (Et-LPS) rats augmented and dysregulated the LPS-induced BBB abnormalities but suppressed apoptosis in neurons.
Singh
Ashok K
AK
Department of Population Diagnostic Medicine, College of Veterinary Medicine, University of Minnesota-Twin Cities Campus, 1333 Gortner Avenue, St Paul, MN 55108, USA. singh001@umn.edu
Jiang
Yin
Y
Gupta
Shveta
S
Benlhabib
Elhabib
E
D000428:Alcohol Drinking / Q000235:genetics* / Q000523:psychology*; D000437:Alcoholism / Q000503:physiopathology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001812:Blood-Brain Barrier / Q000187:drug effects*; D003911:Dextrans / Q000378:metabolism; D004327:Drinking Behavior / Q000187:drug effects; D042783:Endothelial Cells / Q000201:enzymology / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000096:biosynthesis / Q000235:genetics; D007274:Injections, Intraperitoneal; D048031:JNK Mitogen-Activated Protein Kinases / Q000096:biosynthesis / Q000235:genetics; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000633:toxicity*; D008297:Male; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D009474:Neurons / Q000201:enzymology / Q000378:metabolism; D020258:Neurotoxicity Syndromes / Q000503:physiopathology*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013395:Sucrose / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D003911:Dextrans; D008070:Lipopolysaccharides; D016328:NF-kappa B; D012333:RNA, Messenger; D013395:Sucrose; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases