Published online before print June 29, 2009
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* Division of Biology, Kansas State University, Manhattan, Kansas, USA; and
U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Maryland, USA
1. Correspondence: Division of Biology, 18 Ackert Hall, Kansas State University, Manhattan, KS 66506, USA. E-mail: sdflemin{at}ksu.edu
ABSTRACT
Mesenteric IR induces significant inflammation and immune-mediated mucosal damage. TLR4 is a critical receptor in the induction of the inflammatory response and plays a role in intestinal homeostasis. To determine the role of TLR4 in IR-induced epithelial damage, we performed IR studies using TLR4lps-def and TLR4lps-n mice and analyzed mucosal damage and inflammation. We found that the absence of TLR4 or TLR4-induced signaling attenuated local mucosal damage with significantly decreased cytokine and eicosanoid secretion including PGE2 production. Similar results were seen in MyD88–/– mice. Wild-type mice treated with NS-398 (a Cox-2 inhibitor) not only decreased PGE2 production but also attenuated tissue damage. In contrast, PGE2 was not sufficient to induce damage in the TLR4lps-def mice. Together, these data indicate that TLR4 stimulation of Cox-2 activation of PGE2 production is necessary but not sufficient for intestinal IR-induced damage and inflammation.
Key Words: eicosanoids mice innate autoimmunity