重组胸腺素β4对大鼠心肌梗死心微血管及血管内皮生长因子表达的影响

Effects of recombinant thymosin β4 on microvasculature and expression of vascular endothelial growth factor in myocardial infarcted rats

目的：探讨重组胸腺素β4（Tβ4）对心肌梗死大鼠心微血管形成及血管内皮生长因子（VEGF）表达的影响.方法：SD大鼠随机分为对照组、低剂量Tβ4组（0.08μg/100g）和高剂量Tβ4组（0.8μg/100g）,结扎大鼠左冠状动脉前降支,造成永久心肌梗死模型.对照组予PBS,低剂量组和高剂量组予Tβ4腹腔注射,1、5、10d在结扎线以下的部位取材,行碱性磷酸酶和VEGF免疫组织化学显色.结果：各组微血管面积、VEGF阳性细胞平均光密度（AOD）1d差异无统计学意义,给药组10d微血管密度高于对照组,高剂量组5、10d微血管密度高于低剂量组,高剂量组10dVEGF阳性细胞平均光密度高于对照组和低剂量组.结论：Tβ4能促进心肌梗死后微血管形成,增加心肌微血管密度,上调VEGF的表达,从而改善心功能.

Abstract Objective： To study the effects of recombinant thymosin β4 on microvascular generation and expression of vascular endothelial growth factor （VEG-F） after myocardial infarction in rats. Methods：Sprague Dawley rats were randomly divided into a sham group, low-dose （0. 08μg/100 g） and high-dose （0.8μg/100 g） treatment groups. A rat permanent myocardial infarc- tion model was established after tigating left anterior descending coronary artery; the sham group was received PBS treatment, and the treatment groups were received thymosin 134 injections intraperitoneal every day. At 1 day, 5 days and 10 days, the hearts were removed, and the alkaline phosphatase enzyme histochemistry and VEG-F immunohistochemistry were made. Results： There was no significant difference in the microvascular area and average optical density （AOD） of VEGF in each group at 1 day. AOD of VEGF in the 10 day treatment group was higher than that in the sham group, and the microvascular density of high-dose group was higher than that in the low-dose group at 5 and 10 days. The AOD of VEGF positive cells at 10 days of the high-dose group was higher than that of other groups. Conclusion： Our results demonstrate that thymosin β4 can improve cardiac function through promoting myocardial angiogenesis, upregulating expression of VEGF and increasing myocardial microvascular density.