Intestinal ischaemia/reperfusion upregulates beta-defensin-2 expression and causes acute lung injury in the rat.
OBJECTIVE
Human beta-defensin-2 (BD-2) is a positive ion antimicrobial peptide. We investigated the effects of intestinal ischaemia/reperfusion (II/R) on rat BD-2 mRNA and protein expressions in rat lung to address the potential role of BD-2 in acute lung injury (ALI) induced by II/R.


METHODS
Rats were randomly divided into two groups (n=36 each). (i) Sham control and (ii) II/R group (1h superior mesenteric artery clamping, followed by reperfusion of different durations). In II/R group, 6 animals were sacrificed at 0min, 15min, 30min, 60min, 3h and 6h after reperfusion, and serum, lung tissue and bronchoalveolar lavage fluid were harvested. Samples were taken at the corresponding time points in the sham group. Lung histological changes were observed under microscope and the pulmonary permeability index (PPI) was calculated. The lung tissue levels of TNFalpha were detected by ELISA. BD-2 mRNA and protein expressions were examined by RT-PCR and western blotting techniques, respectively.


RESULTS
ALI induced by II/R was confirmed by pathological examination and significantly increased PPI (P<0.05 or 0.01). II/R significantly increased the lung TNFalpha levels and upregulated the expressions of BD-2 mRNA and protein expressions (P<0.05 or 0.01). BD-2 mRNA expression was significantly positively correlated to the lung TNFalpha level (r=0.823, P<0.01) and negatively correlated to PPI (r=-0.615, P<0.05).


CONCLUSIONS
II/R can upregulate BD-2 mRNA and protein expressions in rat lung. BD-2 could be an innate protective factor against II/R-induced lung injury.
Liu
Ke-Xuan
KX
Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China. liukexuan807@yahoo.com.cn
Chen
Shu-Qing
SQ
Zhang
Hui
H
Guo
Jun-ying
JY
Li
Yun-Sheng
YS
Huang
Wen-Qi
WQ
D055371:Acute Lung Injury / Q000209:etiology*; D000818:Animals; D015153:Blotting, Western; D002199:Capillary Permeability / Q000502:physiology; D007422:Intestines / Q000098:blood supply*; D008026:Ligation; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008297:Male; D017538:Mesenteric Artery, Superior; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation; D023083:beta-Defensins / Q000378:metabolism*
D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D023083:beta-Defensins