E Lusha, Nan Jinglong
Department of Cardiology, the Inner Mongolia Autonomous Region People's Hospital, Hohhot 010017, Inner Mongolia, China. Corresponding author: Nan Jinglong, Email:
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2017 Oct;29(10):916-920. doi: 10.3760/cma.j.issn.2095-4352.2017.10.011.
To investigate the effect of high mobility group protein B1 (HMGB1) inhibition on endoplasmic reticulum stress (ERS) after myocardial ischemia/reperfusion (I/R) in rats.
Forty male Sprague-Dawley (SD) rats were randomly divided into four groups (n = 10): sham operation group, I/R model group, Gene silencing (HMGB1-siRNA) group, and empty vector (Scrambled-siRNA) group. Coronary blood flow of the rats were ligated for 30 minutes, relaxed the ligament line for 2 hours, to establish I/R injury model; not ligation with the sham operation group. Each group was injected 1 mL phosphate buffer (PBS), HMGB1-siRNA mixture or Scrambled-siRNA mixture preoperative by tail vein 0 hour, 12 hours, and 24 hours before surgery. After 2 hours reperfusion, the levels of tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-8) in the serum were detected by enzyme linked immunosorbent assay (ELISA); the expression of HMGB1 protein in myocardium was detected by immunohistochemistry; the protein and mRNA expressions of HMGB1, GRP78, CHOP and caspase-12 in myocardium were detected by Western Blot and real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR).
Compared with sham operation group, the levels of serum inflammatory factor, HMGB1 positive cells, and the protein and mRNA expressions of GRP78, CHOP, caspase-12 were significantly increased in I/R model group. The levels of serum inflammatory factor in HMGB1-siRNA group were significantly lower than those in the I/R model group [TNF-α (ng/L): 783.4±203.4 vs. 963.9±214.1, IL-6 (ng/L): 358.8±94.8 vs. 452.3±103.7, IL-8 (ng/L): 180.5±73.6 vs. 347.3±90.3, all P < 0.05], HMGB1 positive cells, and the protein and mRNA expressions of GRP78, CHOP, caspase-12 in HMGB1-siRNA group were significantly lower than I/R model group (HMGB1 protein: 1.59±0.26 vs. 3.21±0.40, GRP78 protein: 2.59±0.28 vs. 4.21±0.42, CHOP protein: 2.01±0.23 vs. 3.21±0.43, caspase-12 protein: 1.48±0.22 vs. 3.01±0.48; HMGB1 mRNA: 2.35±0.26 vs. 4.67±0.45, GRP78 mRNA: 6.59±0.26 vs. 11.21±0.40, CHOP mRNA: 2.01±0.43 vs. 5.21±0.63, caspase-12 mRNA: 4.48±0.32 vs. 8.41±0.52, all P < 0.05). There was no significant difference between the Scrambled-siRNA group and the I/R model group.
HMGB1 may be involved in the activation of ERS in myocardial I/R injury and increase the damage of myocardial cells.
探讨抑制高迁移率族蛋白B1(HMGB1)对大鼠心肌缺血/再灌注(I/R)后内质网应激(ERS)的影响。
将40只雄性Sprague-Dawley(SD)大鼠随机分为四组(n = 10):假手术组、I/R模型组、基因沉默(HMGB1-siRNA)组和空载体(Scrambled-siRNA)组。结扎大鼠冠状动脉血流30分钟,松开结扎线2小时,建立I/R损伤模型;假手术组不结扎。每组在术前0小时、12小时和24小时经尾静脉注射1 mL磷酸盐缓冲液(PBS)、HMGB1-siRNA混合物或Scrambled-siRNA混合物。再灌注2小时后,采用酶联免疫吸附测定(ELISA)法检测血清中肿瘤坏死因子-α(TNF-α)、白细胞介素(IL-6、IL-8)水平;采用免疫组织化学法检测心肌中HMGB1蛋白表达;采用蛋白质印迹法和实时荧光定量逆转录-聚合酶链反应(RT-PCR)检测心肌中HMGB1、葡萄糖调节蛋白78(GRP78)/、C/EBP同源蛋白(CHOP)和半胱天冬酶12(caspase-12)的蛋白及mRNA表达。
与假手术组比较,I/R模型组血清炎症因子水平、HMGB1阳性细胞数及GRP78、CHOP、caspase-12蛋白及mRNA表达均显著升高。HMGB1-siRNA组血清炎症因子水平显著低于I/R模型组[TNF-α(ng/L):783.4±203.4比963.9±214.1,IL-6(ng/L):358.8±94.8比452.3±103.7,IL-8(ng/L):180.5±73.6比347.3±90.3,均P < 0.05],HMGB1-siRNA组HMGB1阳性细胞数及GRP78、CHOP、caspase-12蛋白及mRNA表达均显著低于I/R模型组(HMGB1蛋白:1.59±0.26比3.21±0.40,GRP78蛋白:2.59±0.28比4.21±0.42,CHOP蛋白:2.01±0.23比3.21±0.43,caspase-12蛋白:1.48±0.22比3.01±0.48;HMGBmRNA:2.35±0.26比4.67±0.45,GRP78mRNA:6.59±0.26比11.21±0.40,CHOPmRNA:2.01±0.43比5.21±0.63,caspase-12mRNA:4.48±0.32比8.41±0.52,均P < 0.05)。Scrambled-siRNA组与I/R模型组比较差异无统计学意义。
HMGB1可能参与心肌I/R损伤时ERS的激活,加重心肌细胞损伤。