Mechanism of exercise-induced angiogenesis in rat hippocampi

研究了耐力游泳训练对大鼠血管新生及缺氧诱导因子-2a（HIF-2a）和血管内皮生长因子（VEGF）基因表达的影响。一个对照组的12只大鼠每天洗澡2小时。一个卸载组的12只大鼠每天游泳2小时，没有下沉。负荷组12只大鼠每天进行2小时游泳，颈部挂有体重1.5%的沉子。分别于训练1、3、6周后制备大鼠海马。每组各取一半海马标本进行血管形态计量学分析。其余标本分别进行HIF-2a、VEGF和b-action内对照的mRNA定量分析。负荷组中，游泳训练使5-6 mm直径的毛细血管出现频率增加，单位组织体积毛细血管总长度（CL）平均值增加。此外，它减少了毛细血管的平均直径和毛细血管之间的平均距离（Cd）。与对照组相比，去负荷组CL值和毛细血管总面积最大，Cd值最小。6-7 mm直径的毛细血管出现频率增加。与对照组相比，去负荷组1周后HIF-2a mRNA的表达量明显升高，约为对照组的50%。负荷组在1周、3周和6周后显示出更高的百分比，分别为对照值的1.8倍、1.75倍和1.5倍。提示负荷组海马缺氧程度较非负荷组严重。训练可促进VEGF mRNA的表达。无负荷组在训练1周和3周后VEGF mRNA的表达量均高于对照组。在第1、3、6周，负荷组VEGF mRNA表达量均高于对照组。

It was studied the effects of endurance swim training on the angiogenesis, and the gene expression of hypoxic induced factor-2a (HIF-2a) and vascular endotherial growth factor (VEGF) in rat hippocampi. One control group of 12 rats took a daily bath for 2 h. An unloaded group of 12 rats swam daily for 2 h with no sinker. A loaded group of 12 rats were subjected to daily 2-h swimming with a sinker of 1.5% of own body weight attached to the neck of rat. The rat hippocampi were prepared after 1-, 3-, and 6-weeks training. A half of hippocampal samples in each group was subjected to the morphometrical analysis of blood vessels. The remaining samples were carried on the quantitative analysis of mRNA of HIF-2a, VEGF, and b-action of internal control. In the loaded group, the swim training increased the frequency of small capillary with 5-6 mm in diameter and the mean value of total capillary length per tissue volume (CL). Also, it decreased the mean diameter of capillaries and mean distance between capillaries (Cd). The unloaded group had the largest CL value andmean area of total capillaries, and smaller value of Cd in comparison with the control group. The frequency of capillaries with 6-7 mm diameter increased. Compared with control group, the percentage of HIF-2a mRNA was significantly higher by about 50% of control value in the unloaded group after 1 week. The loaded group showed the higher percentages after 1, 3, and 6 weeks, respectively as 1.8-, 1.75-, and 1.5-fold of control values. This suggests that hypoxic condition in hippocampus was more sever in loaded group than in unloaded group. The training enhanced the expression of VEGF mRNA. In the unloaded group, an amount of VEGF mRNA was higher than control group after 1-and 3-weeks training. Amount of VEGF mRNA was higher in loaded group at weeks 1,3, and 6 than that in control.