贝那普利对小鼠自身免疫性心肌炎CCR2表达的影响

Effect of benazepril on CCR2 expression in experimental autoimmune myocarditis in mice

目的探讨贝那普利对实验性自身免疫性心肌炎(EAM)小鼠心肌组织中CC趋化因子受体2(CCR2)表达的影响。方法60只BALB/c小鼠随机分为对照组、模型组、贝那普利组,每组20只。将提纯的猪心肌球蛋白和完全弗氏佐剂(CFA)等体积混合成乳浊液,模型组与贝那普利组小鼠按0.2ml/只皮下注射免疫,对照组则注射等体积PBS和CFA的混合液。初次免疫当天贝那普利组给予5mg/(kg.d)贝那利普灌胃,其余两组则给予等量生理盐水灌胃。分别于初次免疫后21、90d,比较各组的心重体重比、心肌炎症评分及血清cTnI测定,并采用RT-PCR及免疫组化检测小鼠心肌组织中CCR2的表达。结果21d时,模型组小鼠出现明显心肌炎性浸润,炎症评分、cTnI水平、CCR2mRNA表达(分别为2.49±0.53、2.99±0.80、0.61±0.12)明显高于对照组(分别为0、0.56±0.37、0.35±0.08,P<0.05),贝那普利组(分别为1.63±0.43、1.53±0.36、0.48±0.07)明显低于模型组(P<0.05),但仍高于对照组(P<0.05)。90d时,模型组小鼠心肌组织炎症减弱并伴有纤维化出现,心重体重比、炎症评分、CCR2mRNA表达(分别为5.08±0.09、0.83±0.41、0.49±0.07)明显高于对照组(分别为4.50±0.08、0、0.37±0.08,P<0.05)和贝那普利组(4.65±0.05,0.45±0.33、0.36±0.08,P<0.05),而贝那普利组心重体重比、炎症评分均高于对照组(P<0.05)。结论CCR2在EAM小鼠心肌中表达上调,并参与自身免疫性心肌炎的发生发展过程;贝那普利可以降低CCR2在EAM小鼠心肌中的表达,并抑制心肌炎症。

Objective To investigate the effect of benazepril on CCR2 expression in myocardium in mice with experimental autoimmune myocarditis （EAM）.MethodsSixty BALB/c mice were randomly divided into control group,model group and benazepril group （20 each）.The animals in model group and benazepril group were immunized with the emulsion of isovolumic complete Freund＇s adjuvant （CFA） and cardiac myosin extracted from porcine ventricular myocardium on day 0 and 7 to reproduce the model of experimental autoimmune myocarditis,and the mice in benazepril group were then given 5mg/（kg·d） benazepril by gavage.The mice in control group were immunized with CFA only.On days 21 and 90 after the first immunization,heart weight/body weight （HW/BW） was measured,HE staining was used to identify the areas of inflammation,the serum cTnI level was examined,and CCR2 expression was detected by immunohistochemistry and semi-quantitative RT-PCR.ResultsOn day 21,histopathological examination of cardiac tissue showed an obvious inflammatory cell infiltration with myocyte necrosis in model group.The inflammation score,cTnI level and the expression of CCR2 mRNA in model group （2.49±0.53,2.99±0.80 and 0.61±0.12,respectively） were higher than those in control group （0,0.56±0.37 and 0.35±0.08,respectively,P0.05）,and those in benazepril group （1.63±0.43,1.53±0.36 and 0.48±0.07,respectively） were significantly lower than in model group （P0.05） but higher than in control group （P0.05）.On day 90,fibrosis and a few inflammatory cells could be observed in model group,and the HW/BW,inflammation score and expression of CCR2 mRNA （5.08±0.09,0.83±0.41 and 0.49±0.07,respectively） were higher than those in control group （4.50±0.08,0 and 0.37±0.08,P0.05） and benazepril group （4.65±0.05,0.45±0.33 and 0.36±0.08,P0.05）.HW/BW and inflammation score in benazepril group were higher than those in control group （P0.05）.ConclusionsThe expression of CCR2 mRNA in myocardium is up-regulated in experimental autoimmune myocarditis.CCR2 may play an important role in the pathogenesis and development of autoimmune myocardtis.Benazepril can down-regulate the expression of CCR2 and inhibit cardiac inflammation.