Protective effect of hemoglobin-induced heme oxygenase-1 on injured lungs caused by limb ischemia-reperfusion in rats.
OBJECTIVE
To determine the role of hemoglobin (HB) induced heme oxygenase-1 (HO-1) in injured lungs caused by limb ischemia-reperfusion (I/R) in rats.


METHODS
A rat model of ischemia in the hind limbs was made by clamping the infrarenal aorta with a microvascular clip, and lung injury occurred after reperfusion. To induce the expression of HO-1 in the lungs, Hb was administrated intraperitoneally at 16 hours before reperfusion. Northern blotting and Western blotting were used to detect the expression of HO-1 in the lungs, and the carboxyhemoglobin (COHb) level in arterial blood was assayed. The effect of hemoglobin (Hb) on the injured lungs after limb I/R was determined by measuring the changes of lung histology, polymorphonuclear (PMN) count, malondialdehyde (MDA) content and wet-to-dry weight ratio (W/D). Zinc protoporphyrin (ZnPP), an inhibitor of HO, was used to determine whether HO-1 was induced by Hb after lung injury.


RESULTS
Hb led to a significant increase in HO-1 mRNA and protein expression in the lungs, accompanied by the increase of COHb level in arterial blood. Compared with the sham controls, the lung PMN count, MDA content and W/D significantly increased at 4 hours after limb I/R, which reversed by the pretreatment with Hb at 16 hours before reperfusion. ZnPP blocked this protective role of Hb in the injured lungs.


CONCLUSIONS
Hb can induce the lung HO-1 expression, which plays an important role in the defense against I/R induced lung injury in rats.
Zhou
Junlin
J
Department of Hand Surgery, Third Affiliated Hospital, Hebei Medical University, Shijiazhuang 050051, China. zhoujlin@263.net
Zhu
Xiaoguang
X
Zhang
Guisheng
G
Ling
Tong
T
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002263:Carboxyhemoglobin / Q000032:analysis; D004195:Disease Models, Animal; D006419:Heme Oxygenase (Decyclizing) / Q000032:analysis / Q000096:biosynthesis*; D051547:Heme Oxygenase-1; D006454:Hemoglobins / Q000494:pharmacology*; D008171:Lung Diseases / Q000209:etiology* / Q000473:pathology*; D008297:Male; D011336:Probability; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D015427:Reperfusion Injury / Q000150:complications / Q000378:metabolism*; D012680:Sensitivity and Specificity
D006454:Hemoglobins; D012333:RNA, Messenger; D002263:Carboxyhemoglobin; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1