Withdrawal of alcohol promotes regression while continued alcohol intake promotes persistence of LPS-induced pancreatic injury in alcohol-fed rats.
OBJECTIVE
Administration of repeated lipopolysaccharide (LPS) injections in alcohol-fed rats leads to significant pancreatic injury including fibrosis. However, it remains unknown whether alcoholic (chronic) pancreatitis has the potential to regress when alcohol is withdrawn. The aims of the study were (1) to compare the effect of alcohol withdrawal/continuation on pancreatic acute injury and fibrosis; and (2) to assess the effects of alcohol ± LPS on pancreatic stellate cell (PSC) apoptosis in vivo and in vitro.


METHODS
Rats fed isocaloric Liebere-De-Carli liquid diets ± alcohol for 10 weeks were challenged with LPS (3 mg/kg/week for 3 weeks) and then either switched to control diet or maintained on an alcohol diet for 3 days, 7 days or 3 weeks. Pancreatic sections were assessed for acute tissue injury, fibrosis, PSC apoptosis and activation. Cultured rat PSCs were exposed to 10 mM ethanol 6 1 mg/ml LPS for 48 or 72 h and apoptosis was assessed (Annexin V, caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)).


RESULTS
Withdrawal of alcohol led to resolution of pancreatic lesions including fibrosis and to increased PSC apoptosis. Continued alcohol administration perpetuated pancreatic injury and prevented PSC apoptosis. Alcohol and LPS significantly inhibited PSC apoptosis in vitro, and the effect of LPS on PSC apoptosis could be blocked by Toll-like receptor 4 small interfering RNA.


CONCLUSIONS
Induction of PSC apoptosis upon alcohol withdrawal is a key mechanism mediating the resolution of pancreatic fibrosis. Conversely, continued alcohol intake perpetuates pancreatic injury by inhibiting apoptosis and promoting activation of PSCs. Characterisation of the pathways mediating PSC apoptosis has the potential to yield novel therapeutic strategies for chronic pancreatitis.
Vonlaufen
Alain
A
Pancreatic Research Group, South Western Sydney Clinical School and School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
Phillips
Phoebe A
PA
Xu
Zhihong
Z
Zhang
Xuguo
X
Yang
Lu
L
Pirola
Romano C
RC
Wilson
Jeremy S
JS
Apte
Minoti V
MV
D000428:Alcohol Drinking / Q000009:adverse effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D004195:Disease Models, Animal; D000431:Ethanol / Q000008:administration & dosage* / Q000494:pharmacology; D005355:Fibrosis; D055785:Gene Knockdown Techniques; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D010179:Pancreas / Q000187:drug effects / Q000473:pathology; D058954:Pancreatic Stellate Cells / Q000187:drug effects / Q000473:pathology; D019512:Pancreatitis, Alcoholic / Q000139:chemically induced / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013695:Temperance; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000502:physiology
D008070:Lipopolysaccharides; C495347:Tlr4 protein, rat; D051197:Toll-Like Receptor 4; D000431:Ethanol