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目的:建立近似人类新生儿窒息的病理过程的新生鼠窒息心肌损伤模型,观察心肌HO-1 mRNA、NF-кB表达关系及血中CK-MB、cTnI的变化。方法:正常对照组8只,窒息组80只(分为窒息组40只,窒息+ZnPP组40只)。又分为窒息后6 h,24 h,48 h,72 h,7天,5个不同的时间段采血和心肌样本。①电镜下观察心肌组织细微病变;②原位杂交技术检测HO-1 mRNA在心肌组织的表达;③免疫组化技术检测NF-кB在心肌组织的表达;④ELISA技术检测血中CK-MB、cTnI水平。结果:窒息组:电镜下各时段心肌组织均有线粒体肿胀;核固缩,肌浆网肿胀;窒息+ZnPP组:电镜下各时段均有心肌细胞融合,肌丝溶解,线粒体肿胀,线粒体脊溶解。窒息+ZnPP组的病理损伤比窒息组严重。窒息组血中CK-MB,cTnI水平明显高于对照组,有统计学差异(P<0.01);窒息+ZnPP组血中CK-MB,cTnI水平也明显高于对照组,差异有统计学意义(P<0.01);窒息组血中CK-MB,cTnI水平明显低于窒息+ZnPP组,差异有统计学意义(P<0.05)。窒息组心肌组织细胞HO-1 mRNA表达高于对照组,差异有统计学意义(P<0.01);窒息+ZnPP组心肌细胞HO-1 mRNA表达高于对照组,差异有统计学意义(P<0.05);窒息+ZnPP组与窒息组比较,HO-1 mRNA表达明显降低,差异有统计学意义(P<0.01)。窒息组心肌组织细胞NF-кB表达高于对照组,差异有统计学意义(P<0.01);窒息+ZnPP组心肌细胞NF-кB表达高于对照组,差异有统计学意义(P<0.01);窒息+ZnPP组与窒息组比较,NF-кB表达明显增高,差异有统计学意义(P<0.05)。结论:①新生鼠窒息后心肌组织和细胞受到明显的损伤,CK-MB,cTnI在外周血中明显升高,心肌细胞融合,肌丝溶解,线粒体肿胀;②外周血中CK-MB持续时间较短,cTnI在血中持续时间较长,约7天,提示对心肌损伤的防治应持续至窒息后7天,以免加重心肌损伤和后遗症发生;③HO-1 mRNA表达与NF-кB表达呈负相关;④提示在窒息致心肌损伤的防治中,可适时使用HO-1 mRNA诱导剂,减少炎性细胞因子对心肌的损伤。
OBJECTIVE: To establish a newborn rat model of asphyxia myocardial injury which is similar to the pathological process of neonatal asphyxia in rats. The expression of HO-1 mRNA and NF-κB in myocardium and the changes of CK-MB and cTnI in blood were observed. Methods: 8 normal control group and 80 asphyxia group (40 asphyxia group and 40 asphyxia + ZnPP group). Divided into asphyxia 6 h, 24 h, 48 h, 72 h, 7 days, 5 different time periods of blood and myocardial samples. ① The ultrastructural changes of myocardium were observed under electron microscope; ② The expression of HO-1 mRNA in myocardium was detected by in situ hybridization; ③The expression of NF-κB in myocardium was detected by immunohistochemical technique; ③ CK-MB, cTnI Level. Results: In asphyxia group, mitochondria were swollen in myocardial tissue at each time point under electron microscope; nuclear pyknosis and sarcoplasmic reticulum swelling; asphyxia + ZnPP group: myocardial cell fusion, myofibrillation, mitochondria swelling and mitochondrial ossification . Asphyxia + ZnPP group pathological injury than the asphyxia group. The levels of CK-MB and cTnI in the asphyxia group were significantly higher than those in the control group (P <0.01). The levels of CK-MB and cTnI in the asphyxia + ZnPP group were also significantly higher than those in the control group (P <0.01). The levels of CK-MB and cTnI in asphyxia group were significantly lower than those in asphyxia + ZnPP group (P <0.05). The expression of HO-1 mRNA in asphyxia group was higher than that in control group (P <0.01), and HO-1 mRNA expression in asphyxia + ZnPP group was higher than that in control group (P < 0.05). Compared with asphyxia group, HO-1 mRNA expression in asphyxia + ZnPP group was significantly lower (P <0.01). Compared with control group, the expression of NF-κB in asphyxia group was higher than that in control group (P <0.01); NF-κB expression in asphyxia + ZnPP group was higher than that in control group (P <0.01) ; Asphyxia + ZnPP group compared with asphyxia group, NF-кB expression was significantly increased, the difference was statistically significant (P <0.05). Conclusions ① The myocardial tissues and cells of neonatal rats were obviously damaged after being asphyxiated. CK-MB and cTnI were significantly increased in peripheral blood, cardiomyocyte fusion, myofilament lysis and mitochondria swelling. ② The CK-MB in peripheral blood was longer than that in CK Short, cTnI in blood for a long time, about 7 days, suggesting that the prevention and treatment of myocardial injury should be continued until 7 days after asphyxia, so as not to aggravate myocardial injury and sequelae; ③HO-1 mRNA expression and NF-кB expression was negatively correlated ; ④To prompt the prevention and treatment of myocardial injury caused by asphyxia, HO-1 mRNA inducer can be used in time to reduce the damage of myocardial cells by inflammatory cytokines.