1种新的横向主动脉缩窄大鼠模型构建方法

A novel method of establishing the rat model of transverse aortic coarctation

目的探索1种更优化的横向主动脉缩窄大鼠模型构建方法,为更好地研究压力超负荷诱导的心肌肥厚提供研究基础。方法将36只大鼠分为实验组、胸骨切开组、对照组,每组12只。实验组采用横断大鼠距胸骨约0.5 cm的左侧第3肋骨,经左侧第2、3肋间隙开胸后结扎主动脉弓的方法构建横向主动脉缩窄大鼠模型;胸骨切开组采用传统的直接切开胸骨后结扎主动脉弓的方法构建横向主动脉缩窄大鼠模型;对照组的开胸方法和胸骨切开组一致,但不进行主动脉弓结扎。比较实验组和胸骨切开组的大鼠存活率和手术时间。观察3组大鼠术后一般情况,术后4周采用心脏超声仪测量3组大鼠的舒张末期室间隔厚度(IVSTd)、舒张末期左心室后壁厚度(LVPWTd)、左心室射血分数(LVEF),并利用HE染色和Masson染色观察3组大鼠心脏组织形态学变化和胶原纤维沉积情况。结果实验组、胸骨切开组、对照组分别有1只、6只、3只大鼠死亡,存活率分别为91.7%、50.0%、75.0%。实验组的大鼠存活率高于胸骨切开组,手术时间短于胸骨切开组(均P<0.05)。实验组和胸骨切开组大鼠的IVSTd和LVPWTd均较对照组大鼠增厚(均P<0.05),但实验组和胸骨切开组上述两个指标差异均无统计学意义(均P>0.05)。HE染色和Masson染色结果显示,与对照组比较,实验组和胸骨切开组大鼠心肌组织水肿、炎症细胞浸润和胶原纤维沉积增加。结论与传统经胸骨正中开胸并结扎主动脉弓制备横向主动脉缩窄大鼠模型相比,采用横断距胸骨约0.5 cm的左侧第3肋骨,经第2、3肋间开胸后结扎主动脉弓的方法构建横向主动脉缩窄大鼠模型,手术时间更短,动物存活率更高,且两种模型构建方法在诱导心肌肥厚方面的效果相似。

Objective To explore an optimized method of establishing the rat model of transverse aortic coarctation,and to provide a research basis for preferably studying pressure overload-induced cardiac hypertrophy.Methods A total of 36 rats were assigned to experimental group,sternum incision group,or control group,with 12 rats in each group.The transverse aortic coarctation rat model was established in the experimental group by transverse of the left third rib around 0.5 cm from sternum of rats and ligation of aortic arch after thoracotomy via the second and third intercostal spaces.The transverse aortic coarctation rat model in the sternum incision group was established by ligation of aortic arch after conventional direct incision to sternum.Thoracotomy in the control group was the same as the sternum incision group,but without ligation of aortic arch.The survival rate of rats and operation duration in the experimental group and the sternum incision group were compared.The general status was observed in rates of the three groups.After 4 weeks of operation,the interventricular septum thickness at end diastole(IVSTd),left ventricular posterior wall thickness at end diastole(LVPWTd),and left ventricular ejection fraction(LVEF)of rats in the three groups were measured by using cardiac ultrasound,and the histomorphologic changes and conditions of collagen fiber deposition of rats in the 3 groups were observed by employing the HE staining and Masson staining.Results One,six,and three rats in the experimental group,the sternum incision group,and the control group were died,respectively,with the survival rates of 91.7%,50.0%,and 75.0%,respectively.The experimental group yielded a higher survival rate of rats,and shorter operation duration as compared with the sternum incision group(all P<0.05).The IVSTd and LVPWTd in the experimental group and the sternum incision group were thickened as compared with the control group(all P<0.05);nevertheless,the indices mentioned above depicted no statistically significant difference between the experimental group and the sternum incision group(all P>0.05).The results of HE staining and Masson staining revealed that compared with the control group,rats in the experimental group and the sternum incision group presented as myocardial edema,inflammatory cell infiltration,and increased collagen fiber deposition.Conclusion As compared with the transverse aortic coarctation rat model prepared by conventional thoracotomy via sternum midline and ligation of aortic arch,the transverse aortic coarctation rat model established by employing transverse of the left third rid around 0.5 cm from sternum,and ligation of aortic arch after thoracotomy via the second and third intercostal spaces exhibits shorter operation duration,a higher survival rate of animals,and a similar effect on inducing cardiac hypertrophy.