CXCL12/CXCR4生物轴对慢性病毒性心肌炎小鼠心肌纤维化的影响

摘要

目的 探讨CXCL12/CXCR4生物轴与慢性病毒性心肌炎(CVMC)心肌纤维化的关系.方法 取4周龄BALB/C健康雄性小鼠30只,随机分为对照组(n=10)和CVMC组(n=20).CVMC组以柯萨奇病毒B3株1×10.9/mL腹腔重复增量感染(第0天、14天、28天剂量分别为0.20、0.25、0.30 mL)建立CVMC模型;对照组同期腹腔注射等体积生理盐水.第42天麻醉后行心脏超声检查心率、左室舒张末期内径、左室收缩末期内径、主动脉血流峰值速度,并计算短轴缩短率和射血分数.检查后断髓处死小鼠,取心脏组织进行心肌组织病理学检查及胶原容积测定,计算心肌组织中的胶原容积积分(CVF).采用Western blotting检测心肌组织中CXCL12、CXCR4蛋白表达,RT-PCR检测心肌组织中Ⅰ、Ⅲ型胶原表达.结果 与对照组比较,CVMC组小鼠心肌组织CVF增大,Ⅰ型胶原及Ⅲ型胶原的含量增加,CXCL12、CXCR4蛋白表达增多,差异均有统计学意义(P均<0.05).心肌组织CVF与CXCL12 、CXCR4蛋白表达均呈正相关(r分别为0.79、0.60,P均<0.05).结论 CXCL12/CXCR4生物轴与CVMC心肌纤维化的发生密切相关.%Objective To study the relationship between the CXCL12/CXCR4 biological axis and myocardial fibrosis in chronic viral myocarditis(CVMC).Methods Thirty 4-week-old Balb/c mice were randomly divided into the control group(n=10)and CVMC group(n=20).The mice in the CVMC group were infected with Coxsachie virus B3(CVB3,1×10.9/mL)to establish CVMC models on day 0,14 and 28 with the volume of 0.20,0.25 and 0.30 mL,respectively.The mice in the control group received the equal volume normal of saline.After anesthesia,the heart rate(HR),left ventricular end-diastolic internal diameter(LVDD),left ventricular end-systolic internal diameter(LVSD),and peak velocity of aorta(Vp)at least 3 consecutive cardiac cycles were measured by echocardiography on day 42.Meanwhile,the ejection fraction(EF)and fractional shortening(FS)were calculated.Mice were killed after echocardiographic analysis.Then we counted the ratio of heart weight to body weight(HW/BW).Heart slides were stained with collagen specific picrosirius red staining or HE staining.The collagen volume fraction(CVF)was calculated.The protein expression of CXCL12 and CXCR4 was determined by Western blotting.The mRNA expression of type I collagen and type Ⅲ collagen was determined by RT-PCR.Results Compared with the control group,the CVF,the mRNA expression of type I collagen and type Ⅲ collagen and the protein expression of CXCL12 and CXCR4 significantly increased in the CVMC group(all P<0.05).The CVF was positively correlated with CXCL12 and CXCR4 protein expression in the CVMC group(r=0.79,0.60,all P<0.05).Conclusion CXCL12/CXCR4 biological axis is closely related to CVMC myocardial fibrosis.