亚精胺对心肌梗死大鼠心肌保护的研究

Study on Myocardial Protection of Spermidine in Rats with Myocardial Infarction

目的:观察亚精胺对心肌梗死大鼠心肌缝隙连接蛋白43(Cx43)表达的影响,同步分析对应的心肌保护机制。方法:24只雄性SD大鼠被随机划分为假手术组、心肌梗死模型组、模型+亚精胺组,每组8只大鼠。通过冠状动脉前降支在体结扎手法,成功构建急性心肌梗死的动物模型。假手术组大鼠在左心耳下2 mm位置过线但不结扎,其余操作同心肌梗死模型组;假手术组和心肌梗死模型组大鼠术后给予普通饮用水4周;模型+亚精胺组大鼠术后给予含亚精胺(浓度5 mmol·L-1)饮水4周。采用免疫组化方法检测Cx43在各组中分布特征;采用蛋白印迹技术检测Bcl2关联X蛋白(Bax)、B淋巴细胞瘤–2基因(Bcl–2)、半胱天冬蛋白酶–3(Caspase–3)与细胞色素C(Cytochrome C)的蛋白表达水平。结果:心肌梗死模型组Cx43光密度值显著低于假手术组,差异具有统计学意义(P<0.05);与心肌梗死模型组比较,模型+亚精胺组Cx43光密度值明显增高,差异具有统计学意义(P<0.05)。模型+亚精胺组在闰盘处的Cx43阳性表达明显增多,分布模式接近于假手术组。与假手术组比较,心肌梗死模型组的Bax、Caspase–3与Cytochrome C蛋白表达水平均明显升高,Bcl–2蛋白表达水平明显下降,差异均具有统计学意义(P<0.05);与心肌梗死模型组比较,模型+亚精胺组的Bax、Caspase–3与Cytochrome C蛋白表达水平明显降低,差异均具有统计学意义(P<0.05),但两组在Bcl–2蛋白表达水平上差异无统计学意义(P>0.05)。结论:亚精胺能抑制心肌梗死大鼠心肌Cx43表达减少,减少心律失常,抑制心肌细胞凋亡,保护心肌。

Objective To observe the effect of spermidine on the expression of connexin 43(Cx43)in the myocardium of rats with myocardial infarction,and to analyze the corresponding myocardial protective mechanisms simultaneously.Methods Twenty-four male SD rats were randomly divided into sham operation group,myocardial infarction model group,and model+spermidine group,with 8 rats in each group.An animal model of acute myocardial infarction was successfully constructed through in vivo ligation of the anterior descending coronary artery.The rats in the sham operation group passed the line 2 mm below the left atrial appendage without ligation,and the other operations were the same as those in the myocardial infarction model group.The rats in sham operation group and the myocardial infarction model group were given ordinary drinking water for 4 weeks after surgery,the rats in the model+spermidine group underwent surgery were given drinking water containing spermidine(concentration 5 mmol·L^(-1))for 4 weeks.Immunohistochemistry was used to detect the distribution characteristics of Cx43 in each group.Western blotting was used to detect the protein expression levels of Bcl2-associated X protein(Bax),B lymphoma-2 gene(Bcl-2),Caspase-3 and Cytochrome C.Results The Cx43 optical density value of the myocardial infarction model group was significantly lower than that of the sham operation group,and the difference was statistically significant(P<0.05).Compared with the myocardial infarction model group,The Cx43 optical density value of the model+spermidine group was significantly increased,and the difference was statistically significant(P<0.05).The positive expression of Cx43 in the intercalary disc increased significantly in the model+spermidine group,and the distribution pattern was close to that of the sham operation group.Compared with the sham operation group,the protein expression levels of Bax,Caspase-3 and Cytochrome C in the myocardial infarction model group were significantly increased,and the expression level of Bcl-2 protein was significantly decreased,the differences were statistically significant(P<0.05).Compared with the myocardial infarction model group,the protein expression levels of Bax,Caspase-3 and Cytochrome C in the model+spermidine group were significantly reduced,and the differences were statistically significant(P<0.05),but there was no statistical difference in the expression levels of Bcl-2 protein between the two groups(P>0.05).Conclusion Spermidine can inhibit Cx43 expression,reduce arrhythmia,inhibit myocardial cell apoptosisand and protect myocardium in rats with myocardial infarction.