二乙酰胺三氮脒对肢体缺血再灌注模型小鼠肾损伤的保护作用及其机制

Protective effect of diminazene on kidney injury of limb ischemia-reperfusion model mice and its mechanism

目的:观察血管紧张素转换酶2 (ACE2)激动剂二乙酰胺三氮脒(DIZE)预处理肢体缺血再灌注(LIR)小鼠肾组织中血管紧张素Ⅱ(AngⅡ)、血管紧张素(1-7)[Ang (1-7)]水平和血管紧张素Ⅱ1型受体(AT1R)及Mas受体(MasR)蛋白表达水平,探讨DIZE对LIR小鼠肾损伤的保护作用及其机制。方法:8周龄雄性ICR小鼠18只,随机分为对照组、LIR组和LIR+DIZE组。LIR组和LIR+DIZE组小鼠采用肢体缺血2h再灌注4h方法制备LIR模型,LIR+DIZE组小鼠于LIR前皮下注射DIZE(10mg·kg-1·d-1)预处理14d。采用组织学技术观察小鼠肾组织形态表现并对病理损伤进行评分,化学比色法检测小鼠血清中尿素和血肌酐(Scr)水平,酶联免疫吸附测定(ELISA)法检测小鼠肾组织中AngⅡ和Ang (1-7)水平,蛋白免疫印迹法检测小鼠肾组织中AT1R和MasR蛋白表达水平。结果:与对照组比较,LIR组小鼠肾组织出现炎细胞浸润和上皮细胞变性等不同程度肾损伤改变,肾病理损伤评分升高(P<0.05);与LIR组小鼠比较,LIR+DIZE组小鼠肾组织中肾损伤表现明显减轻,肾病理损伤评分降低(P<0.05)。与对照组比较,LIR组小鼠血清中尿素和Scr水平升高(P<0.05);与LIR组比较,LIR+DIZE组小鼠血清中Urea和Scr水平降低(P<0.05)。与对照组比较,LIR组小鼠肾组织中AngⅡ和Ang (1-7)水平均升高(P<0.05),且AngⅡ/Ang (1-7)比值升高(P<0.05);与LIR组比较,LIR+DIZE组小鼠肾组织中AngⅡ水平降低(P<0.05),Ang (1-7)水平升高(P<0.05),AngⅡ/Ang (1-7)比值降低(P<0.05)。与对照组比较,LIR组小鼠肾组织中AT1R蛋白表达水平降低(P<0.05),MasR蛋白表达水平升高(P<0.05),AT1R/MasR比值降低(P<0.05);与LIR组比较,LIR+DIZE组小鼠肾组织中AT1R和MasR蛋白表达水平均升高(P<0.05),AT1R/MasR比值明显升高(P<0.05)。结论:LIR后小鼠肾组织中AngⅡ/Ang (1-7)和AT1R/MasR表达失衡可能参与LIR后肾损伤的发生,ACE2激活剂DIZE可能通过改善AngⅡ/Ang (1-7)和AT1R/MasR表达失衡发挥对肾脏的保护作用。

Objective:To detect the levels of angioteinsinⅡ (AngⅡ)and angioteinsin(1-7)[Ang(1-7)]and the expression levels of angiotensinⅡtype-1 receptor(AT1R)and Mas receptor(MasR)proteins in kidney tissue of the limb ischemia-reperfusion(LIR)mice pre-treated with the angiotensin coverting enzyme 2(ACE2)activator diminazene(DIZE),and to explore the protective effect of DIZE on the kidney injury of the LIR mice.Methods:Eighteen male ICR mice aged 8 weeks were divided into control group,LIR group and LIR+DIZE group.The mice in model group and LIR+DIZE group were subjected to 2 hof ischemia and 4 hof reperfusion to establish the LIR models.The mice in LIR+DIZE group were pre-treated with 10 mg·kg-1·d-1 DIZE for 14 dby subcutaneous injection before LIR.The histological technique was used to observe the morphology of kidney tissue of the mice and the pathological injury was evaluated.Chemical colorimetry was performed to determine the levels of serum urea and serum creatinine(Scr)of the mice.Enzyme linked immunosorbent assay(ELISA)was used to determine the AngⅡand Ang(1-7)levels in kidney tissue of the mice.Western blotting method was used to measure the expression levels of AT1Rand MasR proteins in kidney tissue of the mice.Results:Compared with control group,the pathological changes such as inflammatory cell infiltration and epithelial cell degeneration were found in kidney tissue of the mice in LIR group,and the kindey injury score was obviously increased(P<0.05);compared with LIR group,the kidney injury performance in the kidey tissue of the mice in LIR+DIZE group was alleviated and the kidney injury score was decreased significantly(P<0.05).Compared with control group,the levels of serum urea and Scr of the mice in LIR group were significantly increased(P<0.05);compared with LIR group,the levels of serum urea and Scr of the mice in LIR+DIZE group were significantly decreased(P<0.05).Compared with control group,the AngⅡ,Ang(1-7)levels and the ratio of AngⅡ/Ang(1-7)of the mice in LIR group were significantly increased(P<0.05);compared with LIR group,the AngⅡlevel of the mice in LIR+DIZE group was markedly decreased(P<0.05),the Ang(1-7)level was significantly increased(P<0.05)),and the ratio of AngⅡ/Ang(1-7)was decreased(P<0.05).Compared with control group,the expression level of AT1R protein in kidney tissue of the mice in LIR group was significantly decreased(P<0.05),the expression of MasR protein was significantly increased(P<0.05),and the AT1R/MasR ratio was decreased(P<0.05).Compared with LIR group,the AT1Rand MasR protein expression levels in kidney tissue of the mice in LIR+DIZE group were significantly increased(P < 0.05),and the AT1R/MasR ratio was also increased(P < 0.05).Conclusion:The imbalance of AngⅡ/Ang(1-7)and AT1R/Mas expressions in kidney tissue of the mice may be involved in kidney injury after LIR of the mice.ACE2 activitor DIZE may play aprotective role in the kidney by improving the imbalance of AngⅡ/Ang(1-7)and AT1R/MasR expressions.