Myocardial ischemia-reperfusion induces β-defensin-2 mRNA expression in lung tissue in rats

Objective To investigate whether rate lung tissue expresses β-defensin-2 mRNA following myocardial ischemia-reperfusion(I/R).Methods Twelve male Wistar rats(weighed 250-300g) were randomly allocated to one of 2 groups(n=6 each): the myocardial I/R group(group C) and sham operation group(group S).Myocardial I/R was produced by slipknot ligation of the left anterior descending coronary artery(LAD).In group C,LAD was occluded for 45 min followed by 3h reperfusion.A needle suture was threaded through under the LAD but not ligated in group S.All animals were sacrificed by exsanguinations at the end of 3 h reperfusion.The serum,lung tissues and bronchoalveolar lavage(BAL) fluid were collected for determination of MB isoenzyme of creatine kinase(CK-MB),pulmonary permeability index(PPI),Western-blotting of BD-2 and TNF-α proteins,and RT-PCR assay of BD-2mRNA expression.Results The levels of serum CK-MB and PPI were all significantly elevated in group C compared with the group S.The BD-2mRNA expression was significantly higher in group C than in group S,so were levels of the BD-2 and TNF-α proteins.There was a positive correlation between levels of BD-2 and TNF-α proteins in group C(r=0.886).Conclusion After myocardial I/R in rats,BD-2 gene expression in lung tissue is up-regulated,along with significant increase in PPI of the lung tissue and levels of BD-2 and TNF-α proteins in the serum.