卡托普利对脓毒症小鼠心肌损伤的保护作用及机制研究

The protective effect and mechanism of captopril on myocardial injury in septic mice

目的:研究卡托普利对脓毒症小鼠心肌损伤的保护作用并探讨其作用机制。方法:按随机数字表法将48只雄性C57BL/6J小鼠(6~8周龄)分为4组:对照组(Control组)、卡托普利组(Captopril组)、脂多糖组(LPS组)、卡托普利+脂多糖组(Captopril+LPS组),每组12只。实验前30 min,Captopril组和Captopril+LPS组预先经腹腔给予卡托普利(50 mg/kg)处理,Control组和LPS组给予等量生理盐水对照。采用腹腔注射脂多糖(LPS,15 mg/kg)的方法制备脓毒症模型(LPS组和Captopril+LPS组),Control组和Captopril组给予等量生理盐水。各组于制模后12 h采集标本,采用无创尾套测压法测量小鼠平均动脉压(MAP),酶联免疫吸附试验(ELISA)法检测血清炎性因子白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平,HE染色观察心肌组织病理形态改变,高分辨小动物超声成像系统检测心功能,Western印迹检测心肌组织磷酸化核因子-κB p65(p-NF-κB p65)蛋白表达。结果:造模后12 h,Captopril组各项指标与Control组比较差异均无统计学意义(均P>0.05)。与Control组相比,LPS组MAP下降(q=4.377,P<0.05);血清IL-6、TNF-α水平明显升高(q=4.966、10.440,均P<0.05);左室射血分数(LVEF%)、左室短轴缩短率(LVFS%)水平明显降低(q=6.104、6.390,均P<0.01);心肌纤维断裂,间质水肿,炎性细胞浸润加重;心肌组织p-NF-κB p65蛋白表达水平明显升高(q=12.430,P<0.001)。和LPS组比较,Captopril+LPS组MAP差异无统计学意义(q=2.617,P>0.05);血清IL-6、TNF-α水平下降(q=4.085、5.721,均P<0.05);LVEF%、LVFS%水平升高(q=4.366、4.297,均P<0.05);心肌损伤病理改变减轻;心肌组织p-NF-κB p65蛋白表达水平下降(q=5.124,P<0.01)。结论:卡托普利可能通过抑制核因子-κB的活化,减少炎性细胞因子(IL-6和TNF-α)产生,抑制脓毒症引起的心肌炎症,从而减轻脓毒症心肌损伤。

Objective:To investigate the protective effect of captopril on myocardial injury in septic mice and its mechanism.Methods:According to the random number table method,48 male C57BL/6J mice(6-8 weeks old)were divided into four groups:control group(Control group),captopril group(Captopril group),lipopolysaccharide group(LPS group),Captopril+lipopolysaccharide group(Captopril+LPS group),12 animals in each group.Captopril group and Captopril+LPS group were pre-treated with Captopril(50 mg/kg)via intraperitoneal administration 30 minutes before the experiment,and Control group and LPS group were given equal amount of saline control.The sepsis models(LPS and Captopril+LPS groups)were prepared by intraperitoneal injection of LPS(15 mg/kg),and the corresponding controls(Control and Captopril groups)were given equal amounts of saline.Specimens from each group were collected 12 h after modeling,and the mean arterial pressure(MAP)of mice was measured by non-invasive tail-sleeve manometry,serum levels of inflammatory factors interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α)were measured by enzyme-linked immunosorbent assay(ELISA),myocardial histomorphological changes were observed by HE staining,cardiac function was detected by high-resolution small animal ultrasound imaging system,and myocardial phospho-NF-κB p65(p-NF-κB p65)protein expression was detected by protein immunoblotting assay(Western blotting).Results:At 12 h post-modelling,there was no statistically significant difference between the indexes of Captopril group and Control group(all P>0.05).Compared with the Control group,MAP decreased in the LPS group(q=4.377,P<0.05);serum IL-6,TNF-αlevels were significantly higher(q=4.966,10.44,both P<0.05);left ventricular ejection fraction(LVEF%)and left ventricular short axis shortening(LVFS%)levels were significantly lower(q=6.104,6.39,both P<0.01);myocardial fibre breakage,interstitial oedema and increased inflammatory cell infiltration;myocardial tissue p-NF-κB p65 protein expression levels were significantly increased(q=12.43,P<0.001).There was no statistically significant difference in MAP between the Captopril+LPS and LPS groups(q=2.617,P>0.05).Serum IL-6,TNF-αlevels decreased in the Captopril+LPS group(q=4.085,5.721,both P<0.05);LVEF%,LVFS%levels increased(q=4.366,4.297,both P<0.05);pathological changes of myocardial injury were alleviated,and the expression level of p-NF-κB p65 protein in myocardial tissue was decreased(q=5.124,P<0.01).Conclusion:Captopril may reduce sepsis myocardial injury by inhibiting the downstream activation of NF-κB and reducing the production of inflammatory cytokines(IL-6 and TNF-α)to suppress the sepsis-induced myocardial inflammatory response.