Increased expression of angiopoietin-2 and Tie2 receptor in a rat model of myocardial ischaemia/reperfusion.
The angiopoietins and Tie receptors are involved in blood vessel formation. The role of the angiopoietin/Tie receptor system in myocardial ischaemia/reperfusion is not well known. To investigate the participation of angiopoietins and Tie receptors in myocardial ischaemia/reperfusion, adult Wistar rats were studied in which the left coronary artery was ligated for 30 min, followed by reperfusion. Angiopoietin-1 (Ang1), angiopoietin-2 (Ang2), Tie1 and Tie2 were measured immediately after relief of occlusion, and 1, 6, 24 and 72 h after reperfusion, by Northern blot, Western blot and immunohistochemical staining. Ang2 mRNA was increased significantly at 24 h and 48 h after reperfusion, and returned to baseline levels at 72 h, in the jeopardized myocardium. Tie2 mRNA increased 3.4-fold immediately after the relief of occlusion, reached a maximum 8-fold increase at 24 h after reperfusion and remained elevated up to 72 h. Ang2 protein levels also increased after reperfusion, reaching a maximum 2.2-fold increase at 48 h after reperfusion. Tie2 protein increased immediately after relief of ischaemia, and showed a significant increase from 6 h to 72 h after reperfusion as compared with the sham control. Ang1 and Tie1 mRNA and protein did not show significant changes after ischaemia/reperfusion. Immunohistochemical studies also showed increased immunoreactivity of Ang2 and Tie2 in the jeopardized myocardium after ischaemia/reperfusion. In conclusion, expression of both Ang2 and Tie2 increased after ischaemia/reperfusion in the rat ventricular myocardium, while the expression of Ang1 and Tie1 did not.
Division of Cardiology, Shin Kong Wu Ho-Su Memorial Hospital, 95 Wen-Chang Rd, Taipei 111, Taiwan.
Kou-Gi
KG
Shyu
Chih-Chuan
CC
Chang
Bao-Wei
BW
Wang
Peiliang
P
Kuan
Hang
H
Chang
D043925:Angiogenesis Inducing Agents / Q000032:analysis / Q000235:genetics*; D042683:Angiopoietin-1; D042702:Angiopoietin-2; D000818:Animals; D015152:Blotting, Northern / Q000379:methods; D015153:Blotting, Western / Q000379:methods; D007150:Immunohistochemistry / Q000379:methods; D008562:Membrane Glycoproteins / Q000032:analysis; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D009206:Myocardium / Q000737:chemistry / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics*; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D017208:Rats, Wistar; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis; D042810:Receptor, TIE-1; D042787:Receptor, TIE-2; D011956:Receptors, Cell Surface / Q000032:analysis; D042764:Receptors, TIE; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D043925:Angiogenesis Inducing Agents; D042683:Angiopoietin-1; D042702:Angiopoietin-2; C467629:Angpt1 protein, rat; C105373:MEN1 protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D020794:Receptor Protein-Tyrosine Kinases; D042810:Receptor, TIE-1; D042787:Receptor, TIE-2; D042764:Receptors, TIE