Dynamic expression of Angiopoietin2/tie2 in rats with myocardial infarction and its relationship with angiogenesis
Wei Ruipeng
Guo Lingyu
Lu Yan
Sun Jing
Jia Yongping
Abstract：Objective To investigate the expression of Angiopoietin2 (Ang2) and its receptor tie2 in the rat after myocardial infarction, and to explore its correlation with angiogenesis after MI in rats.Methods Eighty healthy male SD rats were randomly divided into sham-operation group (n=40) and MI group (n=40). MI model was established by occlusion of the left anterior descending artery, while the sham-operation group were braided of the left anterior descending artery without ligation. Eight rats in both groups were executed randomly at 1, 3, 7, 14, 28 days after model establishment. Meanwhile, serum and myocardial tissues were retained. Enzyme-linked immuno sorbent assay (ELISA) was used to detect the serum expression of Ang2/tie2, the rat cardiac function was evaluated by echocardiography, the myocardial expression of Ang2, tie2 and CD105 were analyzed by immunohistochemical technique.Results ①Echocardiography showed the left ventricular internal diameter at end-diastol (LVIDd) in MI group was significantly higher than those in sham operation group (P<0.01), left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF) were significantly lower than those in sham operation group (P<0.01); compared with the 3 d MI group, the LVEF and LVFS were increased (P<0.05), LVIDd decreased(P<0.05) in 14 d MI group. ② In addition to the 1 d MI group, the levels of serum Ang2 and tie2 in MI group were higher than those in the sham operation group (P<0.05) . The expression of Ang2 in MI group increased gradually over time; compared with the 1 d MI group, the expression of Ang2 increased significantly in other MI groups(P<0.01). Compared with the 3 d MI group, though the expression level of Ang2 in 7 d and 14 d MI groups was increased, there was no statistical significance (P>0.05), the expression of Ang2 in 28 d MI group was significantly higher (P<0.05). However, the expression of tie2 increased slightly at 3 d after operation, decreased slightly at 7 d, and was not significantly higher than that of 1 d MI group (P>0.05), which was significantly higher in 14 d and 28 d MI group(P<0.01). ③The results of immunohistochemistry showed that Ang2 and tie2 were expressed slightly in sham operation group. The expression of Ang2 and tie2 protein in MI group was significantly higher than that in sham operation group, and the expression of Ang2 increased over time. The expression of tie2 did not change in 1 d, 3 d and 7 d MI groups, and increased significantly in 14 d and 28 d MI groups. ④The microvessel density(MVD) of MI group was significantly higher than that of sham operation group at different time points (P<0.05). The MVD increased gradually from 1d to 7 d after operation in MI group, and then maintained at the same level over time.Conclusion The expression of Ang2/tie2 was up-regulated after MI. The expression level of Ang2/tie2 was positively correlated with the number of neovascularization after MI, suggesting that Ang2/tie2 may promote the formation of neovascularization after MI.
Keywords：Myocardial infarctionAngiopoietin2Angiogenesis
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 929-933 )