补体5a受体在阿霉素致急性心力衰竭心肌损伤的早期研究

摘要

目的:探讨补体系统补体5a受体(complement 5a receptor,C5aR)在急性心力衰竭(心衰)早期,对心脏功能影响以及对心肌损伤的作用.方法:选择12 w龄C57BL/6J野生型及C5aR敲除小鼠各12只,分别随机分为野生小鼠对照组、野生小鼠心衰组、C5aR敲除小鼠对照组和C5aR敲除小鼠心衰组等共4组,每组6只.采用单次腹腔注射阿霉素20 mg/kg建立小鼠急性心衰模型,对照组采用同计量0.9％氯化钠液注射；阿霉素注射3d后显微超声检测小鼠心室射血分数和短轴缩短率,处死后测量体质量以及心脏质量；运用半定量PCR、蛋白印迹技术Western Blotting、免疫荧光等实验方法观察C5aR在野生小鼠心脏中的表达.C5aR敲除小鼠心脏组织采用HE染色观察心肌形态、Masson染色观察心肌纤维化程度,WGA染色观察心肌横截面大小,免疫组化染色观察转化生长因子-β(TGF-β)及α-平滑肌肌动蛋白(α-SMA)在心脏中表达.结果:与野生小鼠对照组相比,野生小鼠心衰组中C5aR的mRNA及蛋白表达均显著上调(P＜0.05)；与野生小鼠心衰组相比,C5aR敲除小鼠心衰组体质量及血压均显著升高(均为P＜0.05),心室射血分数和短轴缩短率均显著升高(均为P＜0.05),C5aR敲除小鼠心衰组胶原沉积及α-SMA表达均显著降低(均为P＜0.05),TGF-β表达显著降低(P＜0.01).结论:C5aR在阿霉素诱导心衰模型中表达上调、加重了心肌损伤且促进了心脏纤维化,而C5aR敲除保护小鼠心功能并抑制纤维化,提示C5aR在小鼠急性心衰早期具有促进心脏纤维化作用.%Objective:To study the role of C5a receptor in heart failure in a mouse model induced by doxorubicin (DOX) injection. Methods:The mouse model of heart failure was established by intraperitoneal injection of DOX ( with dosage of 20 mg/kg). 12 week old wild-type and C5aR knockout mice were randomly divided into 4 groups; wild-type saline group, C5aR knockout saline group, wild-type DOX-treated group, and CSaR knockout DOX-treated group. Small animal ultrasound was deformed to examine cardiac function. Mice were sacrificed at day 3. Semi-quantitative PCR, Western Blotting, immunfluorescence were used to determine the CSaR expression. Hematoxylin and eosin (HE) ,Masson's trichrome and immunohistochemistry (TGF-p, a-SMA) staining were used to examine the myocardial injury and fibrosis. Results;Both C5aR mRNA and protein level were significantly increased 3 days after doxorubicin injection. Compared with wild-type mice, CSaR knockout significantly suppressed DOX-induced body weight loss (P < 0. 01 ) , blood pressure change ( P < 0.05) and the level of left ventricular ejection fraction and fractional shortening reduction (P <0.05). Moreover, Dox-induced myocardial vacuolization and fibrosis were significantly reduced (P<0.05). Finally, the expression of pro-inflammation cytokine TGF-p and a-SMA ( myofibroblast marker) were also reduced (P< 0. 05). Conclusion;CSaR is significantly increased in the process doxorubicin-induced acute myocardial injury, and knockout C5aR prevents doxorubicin-induced myocardial fibrosis and inflammation.