家兔脑死亡状态致心脏损伤的相关机制

Mechanism of heart injury in brain death rabbits

目的 观察脑死亡后心脏形态学和相关炎症因子的变化特点,探讨脑死亡致心脏损伤的机制,为临床利用脑死亡供者进行心脏移植提供实验依据.方法 采用随机数字表法将30只家兔平均分为两组,即假手术组和脑死亡组,脑死亡组建立家兔脑死亡模型,假手术组不进行颅内缓慢加压,其他处理两组均相同.两组均在术后2、6、8h记录家兔动脉血压、心率和呼吸变化;HE染色观察心脏组织病理损伤情况;采用酶联免疫吸附试验(ELISA)法检测血浆中白细胞介素1β(IL-1β)、IL-6和IL-8水平;采用逆转录-聚合酶链反应(RT-PCR)和免疫组织化学法检测心脏组织中各炎症相关因子的表达.结果 在家兔脑死亡模型建立成功后8h内,脑死亡组和假手术组家兔动脉血压、心率的差异均无明显统计学意义(P>0.05);病理检查结果显示,脑死亡组心尖组织的病理损伤程度较假手术组明显加重.随着脑死亡时间的延长,脑死亡组家兔血清中IL-6、IL-8的浓度较假手术组显著升高(P<0.05),但在脑死亡后2h内两组间IL-1β水平的差异并无统计学意义(P>0.05).此外,脑死亡组心尖组织中热休克蛋白27(HSP27)、HSP70mRNA表达水平以及ICAM、NF-cB蛋白表达量较假手术组明显增高(P<0.05).结论 随着脑死亡时间延长,心脏组织中炎症因子和血清中白细胞介素含量均增高,表明脑死亡状态使供者心脏发生了炎症反应,从而影响供心质量.

Objective To study the mechanism of brain death-induced heart damage by observing the change patterns of morphological damage to the heart and related inflammatory factors after brain death and provide the experimental basis for heart transplantation by brain-dead donor.Methods The 30 rabbits were equally divided into two groups by the random digital table method:sham-operation group and brain death group.The rabbit brain death model was established in the brain death group,and the sham-operation group was given slow intracranial pressure.The rest treatments in the two groups were the same.At 2nd,6th and 8th h after operation,blood pressure,heart rate and respiratory rate were recorded.The damage of heart tissues was observed by HE staining.The plasma concentrations of IL-1,IL-6 and IL-8 were tested by ELISA.The expression of some inflammatory factors in heart issues was detected by RT-PCR and immunohistochemistry.Results At 8 h after brain death,there was no signifiant difference in blood pressure and heart rate between two groups (P>0.05).The damage of heart issues in the brain death group was more serious than in the shamoperation group.With the prolongation of brain death,the plasma concentrations of IL-6 and IL-8 increased significantly in the brain death group (P<0.05),but the concentration of IL-1β showed no siginificant difference between the two groups at 2 h after brain death (P<0.05).Besides,the expression of HSP27 and HSP70 mRNA as well as the protein expression of ICAM and NF-κB was significantly increased in the brain death group as compared with that in the sham-operation group (P<0.05).Conclusion With the prolongation of brain death time,the inflammatory factors in the heart tissues and plasma interleukin were increased,suggesting the inflammatory reaction occurs in donor heart under the condition of brain death,which influences the quality of donor in the heart transplantation.