缺血期急性高血糖对大鼠心肌缺血/再灌注损伤的影响

Effects of hyperglycemia during myocardial ischemia on myocardial ischemia/reperfusion injury in rats

目的探讨缺血期急性高血糖对大鼠心肌缺血/再灌注(MI/R)后心肌损伤的影响,并分析血糖水平与心肌损伤之间的关系。方法在制备急性大鼠MI/R(缺血30min,再灌注6h)模型的基础上,静脉输注高浓度的葡萄糖溶液,造成2个不同浓度的缺血期急性高血糖动物模型。将32只SD大鼠随机平均分配为4组:(1)假手术组(SHAM),(2)生理盐水对照组(CON),(3)高糖1组(HG1)和(4)高糖2组(HG2)。术中监测血糖水平,再灌注结束后检测心肌酶谱水平和心肌梗死面积(IS)。结果(1)与CON组相比较,HG1组和HG2组缺血期血糖水平均显著升高,分别为(10.5±1.0)、(18.0±1.2)mmol/Lvs(4.7±0.7)mmol/L(P<0.05)。(2)HG1组和HG2组的血肌酸激酶和乳酸脱氢酶水平明显升高,且心肌酶谱与血糖水平存在正相关(r分别为0.80和0.73,P<0.01)。(3)HG1组的IS较CON组有扩大趋势,但差异无统计学意义〔(40.8±5.2)%vs(37.6±5.8)%,P>0.05〕;HG2组的IS明显扩大〔(45.6±8.5)%vs(37.6±5.8)%,P<0.05〕,且IS与血糖水平存在正相关(r=0.57,P<0.01)。结论缺血期急性高血糖加重大鼠MI/R损伤,且血糖水平与心肌酶谱和IS之间存在正相关。

Objective To study the effects of different levels of hyperglycemia on myocardial ischemia/reperfusion injury in rats. Methods Thirty-two SD male rats were subjected to 30 min of myocardial ischemia （MI）and 6 h of reperfusion（R） and were randomly divided into 4 groups ： SHAM（sham operation）, CON（saline administration throughout ischemia and reperfusion period）, HG1 （administration of 25 % glucose by intravenous infusion during ischemia and saline during reperfusion）, HG2 （administration of 50 % glucose by intravenous infusion during ischemia and saline during reperfusion）. The velocity of intravenous infusion was 4 ml/（kg · h）. Blood glucose levels were monitored throughout the experiment. Myocardial infarction size and serum myocardial enzymogram of rats were determined after the experiment. Results ① Blood glucose concentrations significantly increased in HG1 and HG2 groups compared with CON group, being （10.5± 1.0） and（18.0± 1.2） mmol/L vs （4.7±0.7）mmol/L respectively. ② Serum CK and I.DH increased remarkably in HG1 and HG2 groups. There was a positive correlation between blood glucose and CK, LDH levels. ③ There was a trend of increase in infarction size in HGa group compared with CON group, but there was no significant difference[（40.8 ± 5. 2）% vs （37.6±5.8）%, P〉0.05]. Myocardial infarction size enlarged significantly in HG2 group（（45.6 ± 8.5）% vs （37.6 ± 5.8） %, P〈 0.05]. There was a positive correlation between infarction size and blood glucose level. Conclusion Acute hyperglycemia during ischemia significantly exacerbates MI/R injury. Furthermore, there is a positive correlation between hyperglycemia and myocardial injury.