Investigation of mRNA expression of tumor necrosis factor-alpha, interleukin-1beta, and cyclooxygenase-2 in cultured equine digital artery smooth muscle cells after exposure to endotoxin.
OBJECTIVE
To determine messenger RNA expression of cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-alpha, and interleukin- (IL)-1beta from cultured equine smooth muscle cells (SMC).


METHODS
Segments of palmar digital artery harvested from 6 clinically normal adult horses.


METHODS
Explants were collected from the tunica media of arteries for primary culture of SMC. Equine mononuclear cells were used as control cells. Subcultured vascular SMC and control cells were exposed to lipopolysaccharide (20 microg/ml and 100 ng/ml, respectively). Northern blot analysis with equine-specific probes for COX-2, TNF-alpha, and IL-1beta was performed, using isolated total cellular RNA.


RESULTS
Although no message was detected for IL-1beta or TNF-alpha in control or endotoxin-exposed equine vascular SMC from all horses, COX-2 underwent a distinct substantial up-regulation after endotoxin exposure. Endotoxin-exposed equine mononuclear cells had up-regulation of IL-1beta and TNF-alpha mRNA.


CONCLUSIONS
Increased expression of COX-2 mRNA by equine vascular SMC may be an important early pathophysiologic event in the onset of endotoxemia in horses. Potentiated local vascular production of various prostanoids after increased expression of mRNA for COX-2 may result in vasoactive events observed with laminitis.
Rodgerson
D H
DH
Department of Large Animal Surgery and Medicine, College of Veterinary Medicine, Auburn University, AL 36849, USA.
Belknap
J K
JK
Moore
J N
JN
Fontaine
G L
GL
D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D006736:Horses; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000235:genetics; D007527:Isoenzymes / Q000096:biosynthesis* / Q000235:genetics; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000502:physiology; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000662:veterinary; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
D007375:Interleukin-1; D007527:Isoenzymes; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases