| ObjectivesIn this study,we transfected adenoviral vectors with respectively human TK-1 or human TIMP-1 gene and co-expression vector(Ad-hTK-1-hTIMP-1)into acute myocardial Sprague-Dawley rats' model.Ivestigated the role of TK-1 and TIMP-1 and the potential mechanism of ventricular fibrosis in rat myocardial infarction.MethodsRecombinant adenovirus vector our group has been constructed and preserved:Ad5-EGFP,Ad5-hTK-1-EGFP containing TK-1 gene and EGFP gene,Ad5-hTIMP-1containing TIMP-1 gene and EGFP gene.The co-expression vector of TK-1 gene and TIMP-1 gene is referred to as Ad5-hTK-1-hTIMP-1.Acute myocardia infarction model was by ligating left anterior descending(LAD)coronary artery in this study.75 male SD rats weighing 250-300 g were divided into 6 groups,10 rats were used as sham-operated group and the rest rats were randomly divided into 5 groups: PBS group,EGFP group,TK-1 group,TIMP-1 group and co-expression gene group.Sham-operated group only underwent thoracotomy without LAD ligation,the other five groups were treated with LAD ligation and separately injected with PBS,Ad5-EGFP,Ad5-hTK-1,Ad5-hTIMP-1,Ad5-hTK-1-hTIMP-1 through Microinjector.Four weeks after myocardial infarction,the hemodynamic data of rats in each group were measured.The changes of myocardial structure were observed by HE staining and used masson staining to assess the infarct size.Confocal immunofluorescence for TIMP-1 and TK-1and immunohistochemistry for the expression of TGF-?1,type I collagen and type III collagen were performed.We also observed the expression of TGF-?1,pSmad2,Smad2 by western blot.Results1.The rat acute myocardia infarction model was established successfully,afterLAD ligation,ECG ST segment was arched elevation and myocardial surface distal to the suture turn light.2.Compared with the sham-operated group,the infarct size in PBS group and Ad5-EGFP group were increased significantly(P < 0.05),LVSP ? ądp/dtmax were significantly decreased and LVEDP were significantly increased(P < 0.05).Pathological staining showed that inflammatory cell infiltration was obvious,myocardial tissue disorder,fibrous tissue hyperplasia.No significant difference was found in LVSP?ądp/dtmax ?LVEDP and infarct size between EGFP group and PBS group(P>0.05).Compared with the EGFP group,the infarct size and LVEDP were significantly decreased and LVSP? ądp/dtmax were significantly increased in TK-1group,TIMP-1 group and co-expression gene group(P<0.05).Compared with TK-1group or TIMP-1 group,the infarct size and LVEDP were significantly decreased and LVSP?ądp/dtmax were greatly increased in co-expression gene group(P<0.05).3.Compared with the sham-operated group,the expression of TGF-?1,type I collagen,type III collagen and pSmad2 were significantly increased in PBS group and EGFP group(P < 0.05).No significant difference was found in the expression of TGF-?1,type I collagen,type III collagen smad2 and pSmad2 between EGFP group and PBS group(P>0.05).Compared with the EGFP group,the expression of TGF-?1,type I collagen,type III collagen and pSmad2 were significantly decreased inTK-1group,TIMP-1 group and co-expression gene group(P<0.05).Compared with TK-1group or TIMP-1 group,the expression of TGF-?1,type I collagen,type III collagen and pSmad2 were greatly decreased in co-expression gene group(P<0.05).Conclusions1.The rat acute myocardia infarction model was established successfully.Whether gene TK-1 or TIMP-1 injection of myocardial tissue around the myocardial infarction,were successfully transfected and effectively expressed.2.TK-1 or TIMP-1 can decrease the infarct size,inhibits the heart fibrosis,improve cardiac systolic and diastolic function and the ventricular remodeling.Ad5-hTK-1-hTIMP-1 improve ventricular remodeling effect is more significant,mayhave synergistic effect.3.Ad5-hTK-1-hTIMP-1 can inhibits the expression of TGF-?1,type I collagen,type III collagen and pSmad2 after myocardia infarction,possibly through the regulation of TGF-?/Smad2 signaling pathway. |
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