高血流切应力对老年大鼠后肢侧支血管管壁平滑肌的影响

Effect of high flow shear stress on smooth muscle of hindlimb collateral vessel walls in aged rats

目的利用股动脉结扎加股动静脉吻合和单纯股动脉结扎的侧支血管生长模型探讨高血流切应力对老年大鼠后肢侧支血管管壁平滑肌的影响。方法成年大鼠10只及老年大鼠15只,随机分为成年大鼠假手术组、成年大鼠股动脉结扎组、老年大鼠假手术组、老年大鼠股动脉结扎组和老年大鼠股动脉结扎加动静脉吻合组。结扎组行股动脉结扎手术。动静脉吻合组则在股动脉结扎后,将股动脉结扎远侧端与伴随的股静脉行吻合术。动物术后存活1周后,采用免疫荧光组织化学法检测肌球蛋白重链(myosin heavy chain,MHC)和波形蛋白(vimentin)在侧支血管管壁的表达变化。结果与老年大鼠假手术组相比,老年大鼠股动脉结扎组的后肢侧支血管壁vimentin的表达增强,MHC的表达下降;与老年大鼠股动脉结扎组相比,老年大鼠股动脉结扎加股动静脉吻合组的后肢侧支血管壁vimentin的表达显著增强,MHC的表达下降。结论高血流切应力使老年大鼠缺血后肢侧支血管管壁的平滑肌由收缩表型向合成表型转变。

Objective To investigate the effects of high flow shear stress on the smooth muscle of the collateral vessels of hindlimbs in aged rats by using a collateral vessel growth model of femoral artery ligation plus femoral arteriovenous anastomosis and femoral artery ligation alone.Methods 10 adult rats and 15 old rats were divided into adult sham group,adult femoral artery ligation group,aged sham group,aged femoral artery ligation group and aged femoral artery ligation with femoral arteriovenous(AV)shunt group.Femoral artery ligation group was performed with 2 knots.Femoral AV shunt group was created a side-to-side anastomosis between the distal stump of the occluded femoral artery and the accompanying vein.The expression changes of myosin heavy chain(MHC)and vimentin in the collateral vessel walls were examined by immunofluorescence 1 week after surgery.Results Compared with the aged sham group,the expression of vimentin in the hindlimb collateral vessel walls of the aged femoral artery ligation group increased and the expression of MHC decreased.Compared with the aged femoral artery ligation group,the expression of vimentin in the aged AV shunt group increased,and the expression of MHC decreased(p<0.05).Conclusion High flow shear stress changes the smooth muscle of the ischemic collateral vessels wall of the aged rats hindlimb from contraction phenotype to synthetic phenotype.