Expression of angiopoietin-1 and Tie2 receptor during angiogenesis in rats with myocardial infarction / 中国组织工程研究

ABSTRACT

AIM: To investigate the role of angiopoietin-1 (Ang1) and Tie2 receptor in angiogenesis after myocardial infarction through detecting their mRNA expression in normal and infracted myocardium. METHODS: The experiment was conducted in the laboratory of Biochemistry and Molecular Biology, Medical Department of Peking University from April 2006 to April 2007. Forty male SD rats were randomly divided into acute myocardial infarction model group and sham-operation group. The myocardial infarction model was established in the rats of model group through the ligation of left anterior descending artery, while the rats in sham operation group were braided of the left anterior descending artery without ligation. Five rats in both groups were executed at 3, 7, 14, and 28 days after model establishment. RNA was extracted from the same site of left anterior wall, and the polymerase chain reaction was used to semiquantitatively analyze the Ang1 and Tie2 receptor mRNA expression with GAPDH gene as internal control; meanwhile, the immunohistochemistry was used to detect vascular density in and around infarction area. All the treatments for animals were accorded with the animal ethical standards. RESULTS: All 40 rats were included in the final analysis. Both Ang1 and Tie2 receptor were expressed in normal myocardium. In the 28 days after myocardial infarction, Ang1 expression kept at almost the same level without changing, but Tie2 receptor expression was slightly elevated at 3 days, reached peak value at 7 days, and returned to the baseline value at 14 days. The vascular density increased both infarction and peri-infarction area at 7 days after acute myocardial infarction, and did not change with time. CONCLUSION: Tie2 receptor expression is elevated and coincided with angiogenesis after myocardial infarction. It may play a role in the development and stabilization of the blood vessel after myocardial infarction.