Role of interleukin 18 in acute lung inflammation induced by gut ischemia reperfusion.
OBJECTIVE
To study the changes of endogenous interleukin 18 (IL-18) levels and evaluate the role of IL-18 on lung injury following gut ischemia/reperfusion.


METHODS
A superior mesenteric artery occlusion model was selected for this research. The mice were randomly divided into four groups: Sham operation (sham), ischemia (0.5 h) followed by different times of reperfusion (I/R), and I/R pretreated with exogenous IL-18 (I/R+IL-18) or IL-18 neutralizing antibody (I/R+IL-18Ab) 15 min before ischemia. Serum IL-18 levels were detected by Western blot and ELISA, and the levels of IL-18 in lung tissue were evaluated by immunohistochemical staining. For the study of pulmonary inflammation, the lung myeloperoxidase (MPO) contents and morphological changes were evaluated.


RESULTS
Gut ischemia/reperfusion induced rapid increase of serum IL-18 levels, peaked at 1 h after reperfusion and then declined. The levels of IL-18 in lung tissue were gradually enhanced as the progress of reperfusion. Compared with I/R group, exogenous administration of IL-18 (I/R+IL-18) further remarkably enhanced the pulmonary MPO activity and inflammatory cell infiltration, and in I/R+IL-18Ab group, the content of MPO were significantly reduced and lung inflammation was also decreased.


CONCLUSIONS
Gut ischemia/reperfusion induces the increase of IL-18 expression, which may make IL-18 act as an important proinflammatory cytokine and contribute to gut ischemia/reperfusion-induced lung inflammation.
Yang
Yong-Jie
YJ
Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai 200031, China.
Shen
Yun
Y
Chen
Song-Hua
SH
Ge
Xi-Rui
XR
D000208:Acute Disease; D000818:Animals; D020382:Interleukin-18 / Q000276:immunology*; D007422:Intestines / Q000098:blood supply; D017538:Mesenteric Artery, Superior; D051379:Mice; D008810:Mice, Inbred C57BL; D011014:Pneumonia / Q000209:etiology / Q000276:immunology*; D015427:Reperfusion Injury / Q000150:complications / Q000276:immunology*
D020382:Interleukin-18