游泳运动改善幼年自发性高血压大鼠腓肠肌微血管稀少的作用及机制

Swimming exercise improve microvascul rarefaction of gastrocnemius in young spontaneously hypertensive rats and the underlying mechanisms

通过构建长期有氧运动模型,明确游泳运动对幼年自发性高血压大鼠腓肠肌微血管稀少的作用并探讨其机制。采用4周龄雄性大鼠,分为3组:对照组(WKY)、自发性高血压组(SHR)及高血压运动组(SE)。HE染色观察腓肠肌微血管密度、微血管数目与肌细胞数目的比值及肌纤维横截面积的变化,运用免疫组化方法和Western Blot方法检测各组大鼠腓肠肌中VEGF、eNOS、PI3K、Akt的蛋白表达。实验发现:与WKY组相比,SHR组腓肠肌中微血管密度、微血管数目与骨骼肌细胞数目的比值、肌纤维横截面积、腓肠肌总蛋白含量明显减少(P<0.01);8周游泳训练之后,SE组与SHR组相比,各项指标明显增加(P<0.01)。免疫组化和Western Blot实验结果显示:与WKY组相比,SHR腓肠肌中的VEGF、PI3K、Akt、eNOS表达明显下降,SE组腓肠肌中VEGF、PI3K、Akt、eNOS蛋白表达与SHR相比均有明显增加;游泳运动增加了SHR腓肠肌中VEGF、PI3K、Akt、eNOS的蛋白表达。有氧运动可以改善幼年自发性高血压大鼠腓肠肌中微细血管稀少的现象,其机制与运动增加VEGF及eNOS的表达及上调PI3K/Akt信号通路有关。

The aims of this study were to determine the effects of swimming exercise on microvas- cular rarefaction of gastrocnemius in young spontaneously hypertensive rats and to investigate the underlying mechanisms. 4-week-old male rats were divided in to 3 groups, WKY （Wistar Kyoto group）, SHR（spontaneously hypertensive rats group） , SE（spontaneously hypertensive exercise rats group）, SE received 8-week freeloading swimming exercise （1.5 h/day, 5 d/week）. Micro- vascular density,the ratio of the microvascular number to fiber number , fiber cross sectional are- a,total protein content in gastrocnemius and the expressions of VEGF,PI3K,Akt and eNOS in gastrocnemius were determined at the end of exercise. The results show that compared with WKY,microvascular density, the ratio of the microvascular number to fiber number, fiber cross sectional area and total protein content in gastrocnemius tissue were decreased in SHR. Compared with SHR（P〈0.01） ,every detected indexes was significantly increased in SE group at the end of 8-week freeloading swimming exercise （P〈0. 01）. Compared with WKY, the expressions of VEGF,PI3K,Akt and eNOS of gastrocnemius were decreased in SHR. Compared with SHR,the expressions of these proteins were significantly enhanced in SE. Exercise increased the expres- sions of VEGF,PI3K,Akt and eNOS of gastrocnemius in SHR. These data indicated that aerobic exercise improves microvascular rarefaction of gastrocnemius in young spontaneously hyperten- sive rats,which might be attributed to exercise-induced increased expressions of VEGF, eNOS and up-regulated PI3K/Akt signal pathway.