Heme oxygenase modulates small intestine leukocyte adhesion following hindlimb ischemia/reperfusion by regulating the expression of intercellular adhesion molecule-1.
OBJECTIVE
Heme oxygenase is the rate-limiting enzyme in the degradation of heme into carbon monoxide, iron, and bilirubin. Recent evidence suggests that the induction of heme oxygenase-1 is associated with potent anti-inflammatory properties. The objectives of this study were to determine the temporal, regional, and cellular distribution of heme oxygenase-1 within the small intestine and its role in modulating remote intestinal leukocyte recruitment following trauma induced by hindlimb ischemia/reperfusion.


METHODS
Randomized, controlled, prospective animal study.


METHODS
Hospital surgical research laboratory.


METHODS
Male C57BL/6 mice.


METHODS
Mice underwent 1 hr of bilateral hindlimb ischemia, followed by 3, 6, 12, or 24 hrs of reperfusion.


RESULTS
Heme oxygenase-1 messenger RNA, heme oxygenase-1 protein, and heme oxygenase activity were measured using reverse transcription polymerase chain reaction, Western blot, immunohistochemistry, and spectrophotometric assay, respectively. The jejunum was also exteriorized to quantify the flux of rolling and adherent leukocytes and R-Phycoerythrin conjugated intercellular adhesion molecule-1 monoclonal antibody fluorescence intensity in submucosal postcapillary venules with the use of intravital microscopy. Ischemia/reperfusion led to a significant increase in heme oxygenase-1 messenger RNA in the jejunum and ileum 3 hrs following limb reperfusion, with a subsequent increase in heme oxygenase-1 protein and heme oxygenase activity at 6 hrs. Ischemia/reperfusion also led to a significant 1.4-fold increase in leukocyte rolling, whereas inhibition of heme oxygenase via injection of tin protoporphyrin IX (20 micromol/kg intraperitoneally) resulted in a three-fold increase in leukocyte adhesion, compared with ischemia/reperfusion alone. This increase in adhesion was significantly reduced to baseline in mice treated with intercellular adhesion molecule-1 monoclonal antibody before heme oxygenase inhibition (40 microg/mouse), whereas inhibition of heme oxygenase activity following ischemia/reperfusion also led to a significant increase in R-Phycoerythrin intercellular adhesion molecule-1 monoclonal antibody fluorescence intensity.


CONCLUSIONS
Our data suggest that remote trauma induced by hindlimb ischemia/reperfusion leads to an increase in heme oxygenase activity within the small intestine, which modulates intercellular adhesion molecule-1 dependent intestinal leukocyte adhesion.
Scott
Jeffrey R
JR
Medical Biophysics, University of Western Ontario, London, ON, USA.
Gray
Daryl K
DK
Bihari
Aurelia
A
Badhwar
Amit
A
Zhang
Xuchen
X
Shan
Peiying
P
Lee
Patty J
PJ
Chakrabarti
Subrata
S
Harris
Kenneth A
KA
Potter
Richard F
RF
D000818:Animals; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism* / Q000502:physiology; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D007421:Intestine, Small / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D015427:Reperfusion Injury / Q000201:enzymology* / Q000378:metabolism; D014947:Wounds and Injuries / Q000201:enzymology* / Q000209:etiology / Q000378:metabolism
D015815:Cell Adhesion Molecules; D018799:Intercellular Adhesion Molecule-1; D006419:Heme Oxygenase (Decyclizing)