Tumor necrosis factor-α mediates JNK activation response to intestinal ischemia-reperfusion injury.
OBJECTIVE
To investigate whether tumor necrosis factor-α (TNF-α) mediates ischemia-reperfusion (I/R)-induced intestinal mucosal injury through c-Jun N-terminal kinase (JNK) activation.


METHODS
In this study, intestinal I/R was induced by 60-min occlusion of the superior mesenteric artery in rats followed by 60-min reperfusion, and the rats were pretreated with a TNF-α inhibitor, pentoxifylline, or the TNF-α antibody infliximab. After surgery, part of the intestine was collected for histological analysis. The mucosal layer was harvested for RNA and protein extraction, which were used for further real-time polymerase chain reaction, enzyme-linked immunosorbent assay and Western blotting analyses. The TNF-α expression, intestinal mucosal injury, cell apoptosis, activation of apoptotic protein and JNK signaling pathway were analyzed.


RESULTS
I/R significantly enhanced expression of mucosal TNF-α at both the mRNA and protein levels, induced severe mucosal injury and cell apoptosis, activated caspase-9/caspase-3, and activated the JNK signaling pathway. Pretreatment with pentoxifylline markedly downregulated TNF-α at both the mRNA and protein levels, whereas infliximab pretreatment did not affect the expression of TNF-α induced by I/R. However, pretreatment with pentoxifylline or infliximab dramatically suppressed I/R-induced mucosal injury and cell apoptosis and significantly inhibited the activation of caspase-9/3 and JNK signaling.


CONCLUSIONS
The results indicate there was a TNF-α-mediated JNK activation response to intestinal I/R injury.
Department of Gastroenterology, Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510630, Guangdong Province, China.
Qi
Q
Yang
Feng-Ping
FP
Zheng
Ya-Shi
YS
Zhan
Jin
J
Tao
Si-Wei
SW
Tan
Hui-Ling
HL
Liu
Bin
B
Wu
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D004195:Disease Models, Animal; D004789:Enzyme Activation; D007082:Ileum / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D000069285:Infliximab; D007413:Intestinal Mucosa / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D007583:Jejunum / Q000187:drug effects / Q000201:enzymology / Q000276:immunology* / Q000473:pathology; D008026:Ligation; D008297:Male; D008638:Mesenteric Arteries / Q000601:surgery; D008641:Mesenteric Vascular Occlusion / Q000150:complications; D010431:Pentoxifylline / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000201:enzymology / Q000209:etiology / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D014409:Tumor Necrosis Factor-alpha; D000069285:Infliximab; D048031:JNK Mitogen-Activated Protein Kinases; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053453:Caspase 9; D010431:Pentoxifylline
Apoptosis; Intestine; Mucosa; Tumor necrosis factor-α; c-Jun N-terminal kinase