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目的观察低切应力对高血压颈动脉血管重构作用的影响,并初步探讨其信号转导机制。方法分离猪右侧颈总动脉,建立血管体外培养模型,实验分为高切应力组(切应力20 dyn/cm~2,对应灌洗液的流量为200 ml/min)、低切应力组(5 dyn/cm~2,对应灌流液的流量为50 ml/min)及对照组(未经培养的新鲜血管)。镜下测量颈动脉内径及壁厚度,并计算壁横截面积;TUNEL法检测切应力对体外培养猪颈总动脉血管平滑肌细胞凋亡影响;Western blot法检测切应力对体外培养猪颈总动脉血管组织中RhoA、P-MYPT-1、P-ERK1/2、P-JNK和P-P38蛋白表达影响。结果与对照组和高应力组比较,低应力组血管壁厚度和壁横截面积明显增加(P<0.05),血管内径明显变小(P<0.05),内径/壁厚比值明显降低(P<0.05);血管平滑肌细胞TUNEL染色阳性细胞明显增多(P<0.05),凋亡率显著增加(P<0.05);血管组织中RhoA、P-MYPT-1、P-ERK1/2、P-JNK和P-P38蛋白的表达水平明显升高(P<0.05)。结论低切应力对体外培养高血压颈动脉血管重构具有显著地诱导作用,其机制可能与其激活RhoA/ROCK信号,从而引起胞质内丝裂原活化蛋白激酶家族(MAPKs)的3个成员(ERK1/2、JNK、P38)的磷酸化反应有关。
Objective To observe the effect of low shear stress on the remodeling of carotid arteries in patients with hypertension and to explore its signal transduction mechanism. Methods The right common carotid artery was isolated and cultured in vitro. The experiment was divided into high shear stress group (shear stress 20 dyn / cm ~ 2, flow rate corresponding to 200 mL / min), low shear stress group 5 dyn / cm ~ 2, the corresponding perfusate flow rate was 50 ml / min) and the control group (uncultured fresh blood vessels). Carotid artery diameter and wall thickness were measured microscopically, and the wall cross-sectional area was calculated. TUNEL method was used to detect the effect of shear stress on the apoptosis of porcine common carotid artery smooth muscle cells cultured in vitro. Western blot was used to detect the effect of shear stress on porcine common carotid artery RhoA, P-MYPT-1, P-ERK1 / 2, P-JNK and P-P38 protein expression in tissues. Results Compared with the control group and the high stress group, the vascular wall thickness and wall cross - sectional area in the low stress group were significantly increased (P <0.05), the vascular diameter was significantly decreased (P <0.05), and the inner diameter / wall thickness ratio was significantly decreased (P < P-MYPT-1, P-ERK1 / 2 and P-JNK in vascular smooth muscle cells were significantly increased (P <0.05), and the apoptosis rate was significantly increased P-P38 protein expression was significantly increased (P <0.05). Conclusions Low shear stress can significantly induce the remodeling of carotid arteries in hypertensive rats in vitro. The mechanism may be related to the activation of RhoA / ROCK signal, which leads to the activation of three members of mitogen-activated protein kinases (MAPKs) in the cytoplasm ERK1 / 2, JNK, P38) phosphorylation reaction.