| Purpose To investigate the effect of intremedin 1-53 on peroxisome proliferator-activated receptor-γ(PPAR-Y) in lungs of rats with lung ischemia-reperfusion.Methods Seventy-two healthy male Wistar rats were randomly divided into three groups: surgical control group (C group), ischemia-reperfusion group (IR group),and IMD1-53-pretreated group (D group). At each of three time spots(45 min ischemia,60 min and 120 min reperfusion),every 8 rats from the groups were sacrificed,collected for plasma sample and the whole right lung. lung histopathological changes was observed; lung tissue wet/dry weight ratio,MPOactivity,CINC-1 content were determied.;Using immunohistochemistry, we measured PPAR-Y protein in each group; The expressions of PPAR Y mRNA were detected by RT-PCR.Results (1) Histological evaluation:After ischemia-reperfusion,the lung injury was aggravating progressively in the IR group; there was marked pulmonary interstitial edema, capillary congestion, and intraalveolar hemorrhage, infiltration; The pulmonary pathologic alterations occurred to a lesser degree in the D group compared with the IR group.(2) The W/D ratio of lung tissue:There had no significant differences at 45 min ischemia among three groups (P>0.05). In the IR group,The W/D ratio of lung tissue were significantly higher at 60 and 120 min reperfusion(P<0.05). The W/D ratio of lung tissue in the D group were higher than that in the C group(P<0.05),but significantly lower than that in the IR group(P<0.05).(3) The contents of MPO in lung tissue:In both the IR group and D group,The contents of MPO in lung tissue were significantly higher in each same time point after ischemia-reperfusion than that in the C group (P<0.05), but in the D group, the level of MPO was obviously less than that in the IR group(P<0.05). (4) The contents of CINC-1 in lung tissue:the lung CINC-1 contents in IR group increased progressively and was evidently higher than that in C group (P<0.05);but compared with IR group,preadministration of IMD1-53 could inhibit the increase of the CINC-1 contents (P< 0.05). (5) The PPAR-Y mRNA and of PPAR-Y protein in lung tissue:at each spot,the expression of PPAR-Y mRNA was lower in IR group and D group than those in C group (P<0.05),but it was higher in D group than that in IR group; PPAR-γprotein was accordant with PPAR-γmRNA,but was two hours later than PPARγmRNA.Conclusions IMD1-53 treatment before ischemia could protect the lungs against the I/R induced injury by upregulating PPAR-yexpression,activating PPAR-y, and then attenuating the expression of CINC-1 and MPO activity.
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