氯沙坦对自发性高血压大鼠糖基化终末产物及其受体诱导的血管损伤的影响

The Effects of Losartan on Vascular Injury Induced by Advanced Glycation End Products-Receptor of AGE and Its Receptors in Spontaneous Hypertension Rats

背景晚期糖基化终末产物(AGEs)及其受体 RAGE 系统在糖尿病靶器官损伤的病理过程中起非常重要的作用,有研究报道血管紧张素Ⅱ1型受体拮抗剂(ARB)能减少体内外2型糖尿病动物 AGEs 聚集以及氧化应激反应。目的探讨血管氧化应激与 AGE 水平及其受体 RAGE 及核转录因子(NF-kB)等在高血压血管损伤进程中的变化及氯沙坦对其损伤路径的影响。方法选30周龄自发性高血压大鼠(SHR)随机分为 SHR组、氯沙坦组[30 mg/(kg·d)],WKY 组为对照。干预12周,用放免法测定血浆血管紧张素Ⅱ(AngⅡ)水平;免疫荧光检测血管晚期糖基化终末产物(AGEs)表达;免疫组化法检测血管 RAGE 表达。RT-PCR 检测AT_1mRNA、NF-kB mRNA、NADPH 氧化酶 p47 phox mRNA 表达。结果 12周后,SHR 组的血压稳定在治疗前水平[(222±5)mmHg],氯沙坦组血压降至[(158±4)mmHg],且明显低于 SHR 组(P<0.01);氯沙坦组血浆AngⅡ水平达(67.4±5.4)pg/mL,明显高于 SHR 组[(49.5±4.6)pg/mL,P<0.01];氯沙坦组及 WKY 组血管AGEs 表达显著低于 SHR 组;氯沙坦组 RAGE 蛋白表达指数(6.5±0.7)显著低于 SHR 组(8.33±0.95,P<0.01);氯沙坦组 AT_1mRNA、NF-kB mRNA、NADPH oxidase p47 phox mRNA 表达相对系数分别是0.51±0.06、0.39±0.07、0.36±0.05明显低于 SHR 组(0.91±0.12、0.54±0.1、0.54±0.06,P<0.01)。结论高血压病血管内皮细胞氧化应激增加,氯沙坦能通过阻止 AngⅡ与血管紧张素Ⅱ1型受体结合,降低氧化应激抑制AGEs 水平和 RAGE 及 NF-kB 活化等,改善高血压血管重塑。

Background Increasing evidence indicates that Advanced Glycation End Products（AGEs） and the receptor of AGE（RAGE） system play an important role in the pathogenesis of diabetic target organ damage. It has been reported that treatment with an Ang Ⅱ type 1 receptor blocker （ARB） reduced the accumulation of AGEs and diminish nitro-oxidative stress in vitro and in vivo in type 2 diabetes mouse models. Objective To explore the change of the vessels oxidation stress and the AGE, RAGE and NF-κB level in the vessel injury in hypertension, and the effect of losartan. Methods Spontaneous hypertension rats （SHR） at thirty weeks old were randomized to receive losartan （n = 12, 30 mg/kg·d） or placebo （ n = 12）, with WKY rats （ n = 12） as control. Radioimmunity method was used to measure the plasma level of Ang Ⅱ. Immunofluorescence assay and immunohistochemistry to detect the expression of AGEs and RAGE on blood vessles. Expression of AT1 mRNA, NF-κB mRNA and NADPH oxidase p47 phox mRNA were measured by RT-PCR. Results Losartan treatment significantly decreased SBP to 158±4 mmHg （P〈0.01）, with higher plasma Ang Ⅱ level compared with placebo group（losartan： 67.4±5.4 pg/mL vs placebo： 49.5±4.6 pg/mL, P〈0.01）. Losartan markedly reduced the expressions of AGE and the expressions of RAGE proteins（losartan：6.5±0.7 vs SHR：8. 33±0. 95 （P〈0.01）.Losartan also inhibited AT1 mRNA （losartan： 0. 51±0. 06 vs SHR：0. 91±0. 12）, NF-κB mRNA （losartan： 0. 39 ±0. 07 vs SHR：0. 54±0.1） and NADPH oxidase p47 phox mRNA（lorsartan： 0. 36±0.05 vs SHR：0.54±0. 06） （P all〈0. 01）. Conclusions The oxidation stress in vascular vessels was increased in hypertension. Losartan decreases the levels of NADPH oxidase p47phox and AGEs and prevents the activation of RAGE and NF-κB.