Protective effect of heme oxygenase-1 on lung injury induced by erythrocyte instillation in rats.
BACKGROUND
Intratracheal instillation of blood induces self-repaired acute lung injury. However, the mechanism of repair has been unclear. Heme-oxygenase (HO)-1, which catalyzes heme breakdown, acts as an inducible defense against oxidative stress and plays an important role in inflammation. The objective of this study was to test the role of HO-1 in lung injury caused by intratracheal instillation of red cells.


METHODS
Forty healthy, male Sprague-Dawley rats were randomly divided into five groups: normal group, saline group, erythrocyte group, erythrocyte+zinc-protoporphyrin (ZnPP, HO-1 inhibitor) group and saline+ZnPP group. At 2 days after intratracheal instillation of red cells, lung tissues and lavage samples were isolated for biochemical determinations and histological measurements.


RESULTS
Histological analysis revealed that administration of ZnPP worsened the acute lung injury induced by instilled erythrocytes. HO-1 was over-expressed in the erythrocyte group and in the erythrocyte + ZnPP group. Compared with the erythrocyte + ZnPP group, the levels of total protein, lactate dehydrogenase and tumor necrosis factor-alpha in the lavage were lower (P < 0.01), while the level of interleukin-10 was higher in the erythrocyte group (P < 0.01).


CONCLUSIONS
HO-1 protects against erythrocyte-induced inflammatory injury in lung.
Pang
Qing-Feng
QF
Department of Pathophysiology, Xuzhou Medical College, Xuzhou, Jiangsu 221002, China.
Zhou
Qiao-Mei
QM
Zeng
Si
S
Dou
Li-Dong
LD
Ji
Yong
Y
Zeng
Yin-Ming
YM
D000818:Animals; D004912:Erythrocytes / Q000502:physiology*; D006419:Heme Oxygenase (Decyclizing) / Q000032:analysis / Q000502:physiology*; D016753:Interleukin-10 / Q000032:analysis; D008168:Lung / Q000473:pathology; D055370:Lung Injury / Q000517:prevention & control*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat