热休克蛋白70对幼鼠心肌缺血再灌注损伤保护作用的实验研究

The protective effect of heat shock protein70 on the myocardial ischemia-reperfusion injury in immature rats

目的研究川芎嗪(TMP)诱导热休克蛋白(HSP)70对未成熟心肌缺血再灌注损伤的保护作用,探讨其干预心肌缺血再灌注损伤的作用机制及合理用药途径,为临床使用提供理论依据。方法建立幼鼠在体心肌缺血再灌注模型。将96只体重60～75gSD幼鼠(<21d),随机分为3组:(1)假手术(SC)组,(2)缺血再灌注(IR)组,(3)TMP预处理后缺血再灌(TMP+IR)组;每组再随机分为4个亚组:12h亚组、24h亚组、36h亚组、48h亚组,各亚组分别于腹腔药物注射[TMP+IR组腹腔注射TMP(100mg/kg),SC组与IR组腹腔注射等量0.9%氯化钠溶液]后12h、24h、36h、48h制作心肌缺血再灌注模型。测定血清中肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)两种酶的含量,测定幼鼠心肌内HSP70的含量,应用电镜观察幼鼠心肌细胞超微结构的病理改变。结果 IR组和TMP+IR组各时间点血清中CK-MB、LDH含量明显高于SC组(P<0.01);IR组心肌中HSP70表达量较SC组略增加,TMP+IR组HSP70的表达明显增加;电镜心肌细胞超微结构观察:SC组心肌细胞结构基本正常,IR组损伤最严重,TMP+IR组心肌细胞损伤较IR组有明显改善。结论 HSP70的表达可以减轻未成熟心肌的缺血再灌注损伤,可以提高未成熟心肌对损伤性应激的耐受能力。

Objective To investigate the cardioprotective effects of heat shock protein（TMP） on ischemia- reperfusion injury, and to explore its possible mechanisms and rational therapeutic way in order to provide theoretical basis for clinical application. Methods The heart ischemia-reperfusion models were established in 96 immature SD rats weighted 60 - 75g （ 〈 21d） ,then they were randomly divided into three groups：sham operation group （ SC ）, ischemia - reperfusion group （ IR）, TMP pretreatment ischemia - reperfusion group （ TMP ＋ IR）. The hearts of rats were used to make ischemia-reperfusion model at 12h, 24h, 36h, 48h after the pretreatments. All the hearts were subjected to 30 minutes local ischemia, then were reperfused for 120 minutes. The myocardium tissue at each time point was collected, the contents of CK-MB and LDH were measured by biochemistry analyzer. The HSP70 expression was detected by SP method. The uhrastructure changes of myocardium tissue were observed by electron microscope. Results In IR group and TMP ＋ IR group, the contents of CK-MB and LDH were significantly higher than those in SC group （ P 〈 0.01 ）. The expression of HSP70 in IR group was increased after ischemia reperfusion,and the expression of HSP70 increased obviously after TMP pretreatment. The myocardial cellular structures in SC group were normal, however, which were the worst in IR group, the injury was obviously improved in TMP ＋ IR group. Conclusion The expression of HSP70 in rats myocardium tissue can relieve ischemia-reperfusion injury in the heart of immature rat.