The influence and significance of LXA4 on myocardial Na+-K+-ATP enzyme in rats undergoing ischemia reperfusion injury

Objective To investigate the influence and Significance of LipoxinA4 (LXA4) on myocardial Na+-K+-ATP enzyme in rats undergoing ischemia reperfusion injury.Methods Seventytwo SD rats were randomly divided into six groups (n =12):sham operation group one (group C1) ;sham operation group two (group C2) ; MIRI group one (group I/R1) ; MIRI group two (group I/R2) ; pre-MIRI treatment group one (group LX1) ; post-MIRI treatment group two (group LX2).The rat model of MIRI was established,the serum cTnI concentrations were measured in each group before chest opening (T1) and at the end of the experiment (T2).The expression and activity change of Na+-K+-ATP enzyme protein,mRNA were detected.At the same time,myocardial cell apoptosis was detected with TUNEL method,the SOD activation and MDA content were checked,while the ultrastructural changes of cardiac muscle were observed under electron microscope.Results In group I/R1,LX1 (compared with group C1) and group I/R2,LX2 (compared with group C2),the expression levels of Na+-K+-ATP protein (α1:0.19 ± 0.03,0.29 ± 0.05 to 0.46 ± 0.06,0.21 ± 0.03,0.36 ±0.05 to 0.48 ± 0.07,α2:0.20 ± 0.02,0.32 ± 0.04 to 0.54 ± 0.05,0.23 ± 0.03,0.38 ± 0.04 to 0.56 ±0.06,α3:0.24 ± 0.03,0.35 ± 0.04 to 0.61 ± 0.04,0.26 ± 0.03,0.41 ± 0.04 to 0.59 ± 0.04,β1:0.22 ±0.03,0.33 ± 0.04 to 0.56 ± 0.04,0.24 ± 0.03,0.39 ± 0.04 to 0.54 ± 0.04) and mRNA((0.21 ± 0.07) × 106,(0.55 ± 0.28) × 10to (5.73 ± 1.97) × 106,(0.20 ± 0.09) × 106,(1.78 ± 0.86) × 106 to (6.21 ±2.22) × 106).The activities of Na+-K+-ATP (mmol/gprot) were decreased respectively.Serum cTnI concentrations (T2),the apoptotic index and SOD activation (U/mgprot),MDA content (nmol/gprot) all increased significantly (P＜0.05).In group LX1 (comPared with group I/R1) and group LX2 (compared with group I/R2),the expression of Na+-K+-ATP protein,mRNA and activity of Na+-K+-ATP (mmol/gprot),SOD (U/mgprot) were raised significantly,while the serum cTnI concentrations (T2) (ng/L),MDA content (nmol/gprot) and apoptotic index were decreased significantly (P ＜ 0.05).LXA4 had obvious protective effect on myocardial ultrastructure after ischemia reperfusion.Conclusions Before and after MIRI,application of LXA4 could significantly attenuate myocardial oxidative injury,upregulate the expression of Na+-K+-ATP protein and mRNA,enhance the activity of Na+-K+-ATP enzyme.LXA4 plays its role in myocardial protection via the protection of myocardial ultrastructure and reduced apoptosis. Key words: Myocardial reperfusion injury;  Lipoxins;  Na (+)-K (+)-exchanging ATPase; Apoptosis