| Objective:1. To comfirm that myocardial ischemia-preconditioning(IPC) canreduce ischemia-reperfusion injury(I/R) by positivly regulate thesumoylation of Silent information regulator1(SIRT-1) which was inducedby small ubiquitin-related modifier1(SUMO-1) in adult rats.2. To investigate the expression changes and significance of Toll-likereceptor3(TLR3) in myocardial ischemia-reperfusion injury of adult rats.Methods:1.Establishing of animal model: Fourty-eight male Sprague-Dawlerats weighing200-250g were randomly divided into3groups (n=16each):Sham operation group (S group); myocardial ischemia-reperfusion injurygroup (I/R group); myocardial ischemia-preconditioning withischemia-reperfusion group (IPC group). S group was produced by placingthread under anterior descending coronary artery (LAD) but not ligation. I/R group was produced by oppression ligation of LAD for30min followedby120min of reperfusion. IPC group was produced by oppression ligationof LAD for5min followed by5min of reperfusion for three cycles, withoppression ligation of LAD for30min followed by120min of reperfusion.At120min after reperfusion, the rats were decapitated and the hearts werecollected and stored in liquid nitrogen tank for determination.2. SIRT1-sumoylation related index determination: the myocardialinfarct volume was detected by TTC, the protein expression of SUMO-1、SENP-1、 SIRT-1were determinated by western blots, the proteinexpression of SIRT-1/SUMO-1complex was detected by CO-IP.3. TLR3related index determination: the activity of serum LDH、CK,the concentration of TNF-α were determinated by Elisa, the expression ofTLR3mRNA and protein were detected by RT-PCR、 western blotsrespectively, immunohistochemistry was used to detected the expression ofTLR3.Results:1. Compared with group S, the infarct volume fraction was higher ingroup I/R and IPC (P<0.01); Compared with group I/R, the infarct volumefraction was lower in group IPC (P<0.01). Compared with group S, theprotein expression of SIRT-1、SUMO-1were lower in group I/R and IPC(P<0.01); Compared with group I/R, the protein expression of SIRT-1、SUMO-1were elevated in group IPC (P<0.01). Compared with group S, the protein expression of SENP-1、SIRT-1/SUMO-1complex were allsignificantly higher in group I/R and IPC (P<0.01); Compared with groupI/R, the protein expression of SIRT-1/SUMO-1complex was obviouslyelevated in group IPC (P<0.01), while there were no statistical differencesin the protein expression of SENP-1between group I/R and group IPC(P>0.05).2. Compared with group S, the activity of serum LDH、CK, theconcentration of TNF-α, the expression of TLR3mRNA and protein wereall strongly elevated in group I/R (P<0.01). Compared with group I/R, theactivity of serum LDH、CK, the concentration of TNF-α, the expression ofTLR3mRNA and protein were all significantly reduced in group IPC(P<0.01). Immunohistochemistry results showed that TLR3weaklyexpressed in the cytoplasm in group S, while TLR3strongly distributed inthe nucleus and cytoplasm in group I/R and IPC.Conclusion:1. Myocardial IPC can attenuate I/R injury in adult rats, which mightbe related to the significant elevation of the sumoylation of SIRT-1.2. TLR3involved in the levels of myocardial I/R injury in adult rats,and its dynamic expression may indicated or implied the relation to I/Rinjury. |
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