P选择素靶向超声分子成像评价小鼠心肌缺血再灌注损伤

目的 探讨靶向对比超声分子成像评价心肌缺血再灌注损伤的可行性.方法 采用"亲和素-生物素"桥接法构建携抗小鼠P选择素单抗靶向微泡(MBp)和携同型抗体对照微泡(MBC).10只心肌缺血再灌注(IR)小鼠先后注入MBp和MBc(间隔30 min),分别于注入5 min后行心肌对比超声心动图(MCE)检查,测量心肌缺血区和非缺血区的声强度(Ⅵ).结果 对比超声图像显示MBp组缺血区心肌可见造影显著增强,Ⅵ值高达(26.0±6.2)U,而在MBc组缺血区心肌仪见轻度造影增强,Ⅵ值为(9.1±0.9)U,差异有统计学意义(P<0.05).MBp组和MBc组缺血区心肌Ⅵ值均明显高于非缺血区心肌Ⅵ值[(6.5±1.0)U,(6.4±0.8)U,P<0.05].两组非缺血区心肌之间Ⅵ值未见明显差异.结论 应用P选择素靶向对比超声分子成像能够有效评价心肌缺血再灌注损伤.

Evaluation of myocardial ischemia-reperfusion injury in mouse by molecular imaging of P-selectin with targeted contrast echocardiography

Objective To assess the feasibility of evaluating myocardial ischemia-reperfusion injury in mouse with targeted myocardial contrast echocardiography (MCE). Methods Phospholipid microbubbles targeted to P-selectin (MBp) and control microbubbles (MBc) were created by conjugating monoclonal antibody against murine P-selectin or isotype control antibody with the lipid shell via "avidin-biotin" bridging. Ten mice with myocardial ischemia-reperfusion were injected intravenously of MBp and MBc in a random order with a 30 min interval. After 5 min of intravenous injection of microbubble, targeted MCE imaging was performed in all mice. And then the video intensity (Ⅵ) was determined. Results A significant ultrasonic enhancement was observed in ischemic region of MBp-group. Increment in Ⅵ value of ischemic region in MBp-group was great and it amounted to (26.0±6.2)U. However, increment in Ⅵ value of ischemic region in MBc-group was minor and it was merely (9.1±0.9)U. Difference was evident in ischemic region between of two groups (P<0.05). In both MBp-group and M Bc-group, the Ⅵ value of ischemic region was significantly greater than that of non-ischemic region (6.5±1.0 ) U vs (6.4±0.8) U (P<0.05). There was no obvious difference in the Ⅵ of non-ischemic region between two groups. Conclusion Molecular imaging of P-selectin with targeted contrast echocardiogTaphy can effectively evaluate myocardial ischemia-reperfusion injury.