拉西地平对高血压大鼠血管平滑肌细胞CRT和caspase12表达变化的影响

摘要

目的 探讨压力负荷高血压大鼠动脉血管平滑肌细胞内质网应激相关因子钙网蛋白(calreticulin,CRT)和caspase-12的表达变化及药物拉西地平对其的影响.方法 将30只成年雄性SD大鼠随机等分为对照组(sham组)、模型组(TAC组)和拉西地平组(lacidipine组).Sham组分离腹主动脉但不行狭窄术,TAC组行腹主动脉狭窄术,lacidipine组行腹主动脉狭窄术并给予拉西地平0.5 mg/(kg·d),喂养8周用颈动脉插管法测定各组大鼠的平均动脉压(MAP);利用图像分析软件测量血管中层的厚度;用免疫组织化学法和western-blot法检测CRT和caspase-12的表达水平;TUNEL荧光法检测血管平滑肌细胞的凋亡率.结果 ①TAC组大鼠MAP均值显著高于sham组(P＜0.01＝和lacidipine组(P＜0.05＝;lacidipine组大鼠MAP均值高于sham组(P＜0.05＝;②TAC组大鼠血管平滑肌中层厚度均值大于sham组和lacidipine组均有统计学意义(P＜0.05＝,lacidipine组和sham组大鼠血管平滑肌中层厚度比较,差异无统计学意义(P＞0.05);③TAC组的CRT和caspase-12蛋白表达量均值高于sham组和lacidipine组,lacidipine组CRT和caspase-12蛋白表达量均值高于sham组(P＜0.05＝;④TAC组大鼠血管平滑肌凋亡率高于sham组和lacidipine组(P＜0.05＝,lacidipine组大鼠血管平滑肌凋亡率高于sham组(P＜0.05＝.结论 腹主动脉狭窄致高血压可引起血管平滑肌细胞内质网应激反应,导致CRT表达增加及caspase-12的活化增高;拉西地平通过下调内质网应激水平,逆转高血压所致的血管平滑肌细胞的损伤作用,对血管平滑肌细胞具有保护作用.%Objective To investigate the expression changes of calxeticulin ( CRT ) and caspase-12, relative factors of endoplasmic reticulum stress ( ERS ) in vascular smooth muscle cells ( VAMC ), and the influence of lacidip-ine in rats with pressure load hypertension. Methods Adult male SD rats ( n = 30 ) were randomly divided into sham-operation control group ( sham group ), transverse aortic constriction model group ( TAC group ) and lacidipine group. The sham group was given separation of abdominal aorta but no TAC, TAC group was given TAC and lacidipine group was given TAC and lacidipine ( 0. 5 mg/kg · d ). After feeding for 8 weeks,mean artery pressure ( MAP ) was detected in rats of all groups by using carotid intubation. The thickness of aortic media was detected by using imagine analysis software. The expressions of CRT and caspase-12 were detected by using immunohistochemistry technique and Western-blot method,and apoptotic rate of VAMC was detected by using TUNEL method. Results ①The average value of MAP was significantly higher in TAC group than that in sham group ( P <0. 01 ) and lacidipine group ( P <0. 05 ),and that was higher in lacidipine group than that in sham group ( P <0. 05 ). ②The average value of thickness of aortic media was higher in TAC group than that in lacidipine group and sham group ( P<0.05 ),and that was no statistically significant between lacidipine group and sham group ( P >0. 05 ). ③The average values of protein expressions of CRT and caspase-12 were higher in TAC group than those in lacidipine group and sham group,and those were higher in lacidipine group than those in sham group ( P <0. 05 ). ④The apoptotic rate of VAMC was higher in TAC group than that in sham group and lacidipine group ( P < 0.05 ), and that was higher in lacidipine group than that in sham group ( P < 0. 05 ). Conclusion Hypertension induced by abdominal aortic stenosis can cause ERS response of VSMC and promote CRT expression and activation of caspase-12. Lacidipine can reverse the injury of VSMC induced by hypertension and protect VSMC through down-regulating ERS level.