脓毒症心肌功能障碍模型大鼠的构建与评价

Constructing and assessing a rat model of sepsis-induced myocardial dysfunction

背景:目前认为心肌线粒体结构与功能的损伤在脓毒症心肌功能障碍中起着关键作用。目的:构建大鼠脓毒症心肌功能障碍模型,为研究该疾病提供有效的实验手段。方法:72只清洁级雄性SD大鼠随机分为对照组28只、脂多糖组44只;两组大鼠各随机抽取20只用于观察造模后10 d生存率;脂多糖组剩余24只依据造模后时相分为脂多糖6,12,24 h组3个亚组,每组8只。脂多糖组腹腔注射10 mg/kg脂多糖建立大鼠脓毒症模型,对照组注射等量生理盐水。脂多糖各亚组分别于各时相点行超声心动图检查心功能。留取心肌组织光镜观察心肌组织病理形态结构,透射电镜观察心肌超微结构;ELISA法检测大鼠静脉血清心肌肌钙蛋白、脑钠肽浓度。实验经宁夏医科大学总医院伦理审查委员会批准(审批号:2018-320)结果与结论:①与对照组比较,脂多糖组大鼠10 d生存率明显降低;②与对照组比较,脂多糖6 h组左室射血分数、左室缩短分数未见降低(P均>0.05),脂多糖12 h组、脂多糖24 h组左室射血分数、左室缩短分数显著降低(P均<0.01),且随时间延长降低更明显(P均<0.01);③与对照组比较,脂多糖12 h组、脂多糖24 h组血清肌钙蛋白Ⅰ、脑钠肽水平升高(P均<0.01),且随脂多糖注射时间延长,肌钙蛋白Ⅰ、脑钠肽水平逐渐升高(P均<0.01);④脂多糖各组心肌病理形态及超微结构与对照组比较出现明显损伤,且随着脂多糖注射时间延长损伤加重;⑤结果说明,实验成功建立大鼠脓毒症心肌功能障碍模型,该模型稳定可靠。

BACKGROUND: It is currently believed that myocardial mitochondrial structure and function damage play a key role in sepsis-induced myocardial dysfunction. OBJECTIVE: To construct a rat model of sepsis-induced myocardial dysfunction and provide an effective experimental method for studying the disease. METHODS: Seventy-two SPF male Sprague-Dawley rats were randomly divided into control group (n=28) and lipopolysaccharide (LPS) group (n=44). Twenty rats were randomly selected from each group for observation of 10 days of survival. According to the post-modeling phase, the remaining 24 rats of the LPS group were divided into three subgroups, LPS 6-hour group, LPS 12-hour group and LPS 24-hour group, with 8 rats in each group. A sepsis model was constructed by intraperitoneal injection of 10 mg/kg LPS in the LPS group, and the control group was injected with an equal volume of normal saline. Echocardiographic examination of cardiac function was performed at each phase in each LPS subgroup. Myocardial histopathological morphology was observed by light microscopy, and myocardial ultrastructure was observed by transmission electron microscopy. Serum cardiac troponin and brain natriuretic peptide levels were measured by ELISA. The study was approved by the Ethic Committee of General Hospital of Ningxia Medical University in China (approval No. 2018-320). RESULTS AND CONCLUSION: Compared with the control group, the 10-day survival rate of rats in the LPS subgroups was lower. Compared with the control group, there was no reduction in left ventricular ejection fraction and left fractional shortening in the LPS 6-hour group (both P > 0.05). While in the LPS 12-hour group and LPS 24-hour group, the left ventricular ejection fraction and left fractional shortening significantly decreased (all P < 0.01), and the decrease was more obvious with time (all P < 0.01). Compared with the control group, the serum cardiac troponin and brain natriuretic peptide levels were significantly increased in the LPS 12-hour group and LPS 24-hour group (all P < 0.01), and the serum cardiac troponin and brain natriuretic peptide levels gradually increased with LPS injection time (all P < 0.01). The myocardial pathological morphology and ultrastructure of the LPS subgroups showed obvious damage compared with the control group, and the damage was more obvious with the prolongation of LPS injection time. In this experiment, we successfully constructed a stable and reliable model of sepsis-induced myocardial dysfunction in rats, which is an ideal animal model for clinical research of sepsis cardiomyopathy.