长期高盐饮食及替米沙坦干预对Wistar大鼠动脉重构的影响

Effects of long-term high salt diet and intervention of telmisartan on arterial remodeling in Wistar rats

目的观察长期高盐饮食对Wistar大鼠主动脉和肠系膜动脉重构的影响,探讨长期高盐饮食致大鼠动脉重构的可能机制及血管紧张素受体拮抗剂替米沙坦的干预作用。方法 Wistar大鼠49只分为:对照组(n=13,给予0.5%NaCl的颗粒饲料)、高盐模型组(n=24,给予8%NaCl的颗粒饲料)、干预组[n=12,给予8%NaCl的颗粒饲料+替米沙坦2～40mg/(kg·d)]。每两周测量尾动脉压一次,喂养共24周。采用HE染色、Masson染色、免疫组化染色观察主动脉和肠系膜动脉中膜形态结构变化及增殖情况,酶学比色法检测细胞膜钠泵及钙泵活性,实时荧光定量PCR法检测细胞膜钠泵及钙泵mRNA表达水平。结果与对照组比较,实验末高盐模型组大鼠尾动脉血压明显升高[(152.9±32.1)比(119.5±7.2)mm Hg,P<0.05],主动脉及肠系膜动脉中膜厚度、中膜厚度/腔径、胶原纤维面积百分比值和增殖细胞核抗原(PCNA)阳性表达百分比明显增高,主动脉平滑肌组织Na+-K+-ATP酶及Ca2+-ATP酶活性降低[(8.80±1.98)比(11.14±2.23);(7.81±1.59)比(10.56±2.67)μmol Pi/(h·mg pro),均P<0.05],主动脉平滑肌组织钠泵α1亚单位基因表达降低[(81.0±12.0)比(172.0±25.7),P<0.05],细胞质膜钙泵亚型1基因表达明显升高(238.0±27.0比90.0±23.9,P<0.01)。与高盐模型组相比,实验末干预组血压[(127.8±4.3)比(152.9±32.1)mm Hg,P<0.05]、主动脉和肠系膜动脉中膜厚度、中膜厚度/腔径、胶原纤维面积百分比值、PCNA阳性表达百分比均降低。相关分析显示高盐模型组ATP酶活性与上述血管重构指标均呈负相关。结论长期高盐饮食可导致血压升高和主动脉及肠系膜动脉重构,细胞离子泵活性降低及其基因表达异常可能是高盐诱导动脉重构的机制之一。替米沙坦能够抑制血管平滑肌增生和胶原堆积、阻止高盐诱导的高血压和动脉重构。

Objective To investigate the effects and mechanism of long-term high salt diet and telmisartan on aorta and mesenteric artery remodeling in Wistar rats. Methods A total of 49 Wistar rats were divided into control group（group C, n=13, receiving 0.5% NaC1 pellet）, high salt model group （group M, n=24, receiving 8% NaC1 pellet）, and intervention group [group T, n=12, receiving 8% NaC1 pellet and telmisartan 2-40 mg/（kg · d）]. Artery pressure was determined every two weeks. After 24 weeks, HE staining, masson staining and immunohisto- chemistry were used to observe the morphology changes of arteries and evaluate the fibrosis and proliferation. The activities and mRNA levels of Na^＋ pump and Ca^2＋ pump in aortic media were determined by enzyme colorimetry and real-time polymerase chain reaction （PCR）respectively. Results Compared with group C, the blood pressure of group M was higher [（152.9±32.1） vs （119.5±7.2） mm Hg, P〈0.05], media thickness, ratio of media thick-ness to lumen diameter（MT/LD）, the collagen volume fraction（CVF）, and proliferating cell nuclear antigen（PCNA） expression of aorta and mesenteric arteries were significantly increased. The activities of Na^＋-K^＋-ATPase and Ca^2＋-ATPase E[8. 80±1.98） vs （11.14±2.23） ; （7.81±1.59） vs （10.56±2.67） μmolPi/（h · mg pro）, all P〈0.05], the mRNA expression of Na^＋-K^＋-ATPase a1 subunit [（81.0±12.0） vs （172.0±25.7）, P〈0.05-1 were decreased in aortic smooth muscle, whereas calcium pump isoform 1 mRNA expression in group M was significantly increased in plasma membrane [（238.0±27.0} vs （90.0±23.9）, P〈0.01]. Treated by telmisartan, blood pres-sure E（127.8±4.3） vs （152.9±32. 1） mm Hg,1, media thickness, MT/LD, CVF and PCNA in aorta and mesenter-ic arteries were all markedly decreased. Correlation analysis showed that ATPase activities were negatively correla-ted with the above vascular remodeling indexs. Conclusions Long-term high-salt diet could lead to elevated blood pressure and arterial remodeling. The abnormality of ion pump activity and gene expression may play important role in the arterial remodeling. Telmisartan may inhibit the proliferation of vascular smooth muscle and collagen ac-cumulation, and prevent salt-induced hypertension and arterial remodeling.