被动靶向心肌超声造影评价大鼠心脏移植术后急性排斥反应

目的探讨白细胞被动靶向心肌超声造影对心脏移植术后急性排斥反应的诊断价值。方法成功建立20只大鼠腹部异位心脏移植模型,其中同种异体移植12例(实验组),同系移植8例(对照组)。术后第3天,将声诺维(SonoVue)经静脉持续注入大鼠体内,应用心肌超声造影技术观察异位移植心脏,分别取得注入造影剂20 s时的心肌灌注图像和5 min时的白细胞被动靶向心肌造影图像,利用图像分析仪分别测定其造影图像灰阶值(GS_(20s)、GS_(5m)),靶向灰阶值(GS_(target))为同一只大鼠的GS_(5m)与GS_(20s)之差。观察完毕后处死大鼠行病理检查,HE染色确定移植心肌排斥程度,免疫组织化学检测移植心组织内CD3~+T细胞浸润程度,将随机10个高倍视野下的CD3~+T细胞数量定为CD3~+细胞记数,并将其分别与GS_(20s)、GS_(5m)、GS_(target)做相关分析。结果心肌灌注成像显示实验组GS_(20s)稍低于对照组GS_(20s)(P0.05),但差异无统计学意义。白细胞被动靶向心肌造影显示实验组GS_(5m)明显高于对照组GS_(5m)(P0.001),且GS_(target)实验组显著高于对照组(P0.001)。HE染色移植心肌显示对照组多为正常心肌组织,而实验组心肌多为Ⅲ～Ⅳ级排斥反应,免疫组织化学检测显示CD3~+细胞记数实验组较对照组显著增高(P0.001),相关分析显示:CD3~+细胞记数与GS_(target)呈明显正相关(r=0.79,P0.001)。结论白细胞被动靶向心肌超声造影技术能无创、有效地评价心脏移植术后的急性排斥反应。

Evaluation of Acute Rejection Aftert Cardiac Transplantation with Leukocyte-Targeted Myocardial Contrast Echocardiography

Objective To discuss the value of leukocyte-targeted myocardial contrast echocardiography as a tool in observing acute rejection after heart transplantation.Methods Abdominal heterotopic cardiac transplantation was performed in 20 rats successfully,among which 12 allografts were as rejection group and 8 isografts were as control group.Myocardial contrast echocardiography(MCE) was performed during continuous intravenous SonoVue injection postoperatively on the third day after operation.We performed 2 types of MCE:perfusion imaging and leukocyte-targeted imaging.The images were obtained at 20 seconds and 5 minutes after injection of contrast agent.Measure the value of the contrast image grayscale (GS) by image analyzer(GS_(20s)、GS_(5m)).GS_(target) was calculated as the GS_(5m) minus the GS_(20s) in the same rat.Postmortem histology was performed after observation.The degree of myocardial rejection was determined by HE-stained graft myocardium.Immunohistochemistry was performed to quantify the CD3-positive cell,and correlation analysis was performed between CD3-positive cell count and GS_(20s)、GS_(5m)、GS_(target).Results Perfusion imaging showed Myocardial GS_(20s) slightly decreased in rejecting versus control rats (P>0.05).Leukocyte-Targeted imaging showed Myocardial GS_(5m) significantly higher in rejecting versus control rats (P<0.001).GS_(target) was significantly higher in rejecting versus control rats (P<0.001).Postmortem histology showed normal myocardium in control rats,whereas allograft myocardium demonstrated grade Ⅲ to Ⅳ rejection.Immunohistochemistry showed the CD3-positive cell infiltration was significantly higher in rejecting versus control(P<0.001).There was a significant positive correlation between the CD3-positive cell and GS_(target)(r=0.79,P<0.001).Conclusions Leukocyte-Targeted contrast echocardiography may thus offer a noninvasive and effective ultrasound imaging technique for the detection of acute cardiac transplant rejection.