Liao Ruyi, Zhang Jianfeng, Zhao Huimin, Zhang Zongxiang, Yang Kang
Department of Emergency, the Second Affiliated Hospital of Guangxi Medical University, Nanning 530007, Guangxi Zhuang Autonomous Region, China.
Department of Cardiology, the Second Affiliated Hospital of Guangxi Medical University, Nanning 530007, Guangxi Zhuang Autonomous Region, China. Corresponding author: Zhao Huimin, Email:
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2020 Feb;32(2):210-214. doi: 10.3760/cma.j.cn121430-20191024-00039.
To investigate the effects and mechanisms of low-dose hydrocortisone on myocardial injury in early septic shock rats.
Seventy-two healthy male Sprague-Dawley (SD) rats were divided into Sham group, lipopolysaccharide (LPS) model group (LPS group) and low dose hydrocortisone intervention group (LD group) according to the random number table method, with 24 rats in each group. The rat model of septic shock was produced by intravenous injection of LPS at 20 mg/kg. Sham group was injected with an equal amount of physiological saline. The LD group was injected 5 mg/kg of hydrocortisone via right femoral vein after model establishment. Sham group and LPS group were injected with an equal amount of physiological saline. Blood pressure and heart rate (HR) of rats in each group were continuously monitored. In each group, 8 rats were sacrificed for arterial blood gas analysis at 0, 3 and 6 hours after model establishment, and the level of plasma N-terminal B-type brain natriuretic peptide precursor (NT-proBNP) was detected by enzyme linked immunosorbent assay (ELISA). The expressions of cleaved-caspase-3 and nuclear factor-κB p65 (NF-κB p65) were detected by Western Blot. Myocardial tissue was harvested 6 hours after model establishment, the histopathological changes were observed by hematoxylin eosin (HE) staining, and the apoptosis rate of myocardial cells was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL).
After LPS injection, mean arterial pressure (MAP) decreased significantly at 1 hour, then gradually increased, and was significantly higher than Sham group at 6 hours. There was no significant change in HR, and the difference was not statistically significant compared with Sham group. Blood lactic acid (Lac), base excess (BE), plasma NT-proBNP level, myocardial tissue caspase-3 and NF-κB p65 expression increased with the extension of time, all reach the peak in 6 hours, and significantly higher than Sham group. After early treatment with low-dose hydrocortisone in septic shock, MAP showed an increasing trend and Lac, BE decreased slowly. At 6 hours, MAP, Lac and BE were significantly lower than those in the LPS group [MAP (mmHg, 1 mmHg = 0.133 kPa): 98.6±7.5 vs. 106.1±8.5, Lac (mmol/L): 1.29±0.08 vs. 2.42±0.37, BE (mmol/L): 4.45±0.57 vs. 8.18±1.03, all P < 0.05]. The level of plasma NT-proBNP, and the expressions of caspase-3 and NF-κB p65 in myocardial tissue were significantly lower than those in LPS group at 3 hours and 6 hours after low-dose hydrocortisol treatment [NT-proBNP (ng/L): 2 740.56±97.31 vs. 4 425.60±743.32 at 3 hours, 2 638.81±205.12 vs. 4 993.01±373.78 at 6 hours; caspase-3/GAPDH: 0.567±0.045 vs. 0.841±0.162 at 3 hours, 0.496±0.071 vs. 1.116±0.172 at 6 hours; NF-κB p65/GAPDH: 0.852±0.734 vs. 1.232±0.115 at 3 hours, 0.783±0.047 vs. 1.383±0.215 at 6 hours, all P < 0.05]. HE staining results showed that myocardial cells in the LPS group were broken and inflammatory cells infiltrated. The myocardial histopathological changes in LD group were significantly less than those in LPS group. TUNEL staining showed that the apoptosis of myocardial cells in LPS group increased, and the apoptosis rate was significantly higher than that in Sham group [(82.41±1.57)% vs. (5.77±0.69)%, P < 0.05]. The apoptosis rate in LD group was significantly lower than that in LPS group [(27.82±1.77)% vs. (82.41±1.57)%, P < 0.05].
Low-dose hydrocortisone plays a protective role in the myocardial injury of early septic shock, and its mechanism may be related to the inhibition of caspase-3 and NF-κB p65 expression, the reduction of apoptosis rate and myocardial inhibition.
探讨小剂量氢化可的松对早期脓毒症休克大鼠心肌损伤的影响及其机制。
将72只健康雄性Sprague-Dawley（SD）大鼠按随机数字表法分为假手术组、脂多糖（LPS）模型组（LPS组）和小剂量氢化可的松干预组（LD组），每组24只。通过静脉注射20 mg/kg LPS制备脓毒症休克大鼠模型。假手术组注射等量生理盐水。LD组在模型建立后经右股静脉注射5 mg/kg氢化可的松。假手术组和LPS组注射等量生理盐水。持续监测各组大鼠的血压和心率（HR）。每组在模型建立后0、3和6小时处死8只大鼠进行动脉血气分析，采用酶联免疫吸附测定（ELISA）法检测血浆N末端B型脑钠肽前体（NT-proBNP）水平。采用蛋白质免疫印迹法检测裂解的半胱天冬酶-3（cleaved-caspase-3）和核因子κB p65（NF-κB p65）的表达。在模型建立后6小时采集心肌组织，采用苏木精-伊红（HE）染色观察组织病理学变化，采用末端脱氧核苷酸转移酶介导的缺口末端标记法（TUNEL）检测心肌细胞凋亡率。
注射LPS后，平均动脉压（MAP）在1小时显著下降，随后逐渐升高，在6小时显著高于假手术组。HR无显著变化，与假手术组相比差异无统计学意义。血乳酸（Lac）、碱剩余（BE）、血浆NT-proBNP水平、心肌组织caspase-3和NF-κB p65表达随时间延长而增加，均在6小时达到峰值，且显著高于假手术组。早期小剂量氢化可的松治疗脓毒症休克后，MAP呈上升趋势，Lac、BE缓慢下降。在6小时时，MAP、Lac和BE显著低于LPS组[MAP（mmHg，1 mmHg = 0.133 kPa）：98.6±7.5 vs. 106.
