Establishment and stability assessment of mouse cervical heterotopic heart transplantation model with "Anchoring Node"

Abstract

Objective To optimize the operational steps and processes in mouse cervical heterotopic heart transplantation by modifying the conventional cuff technique for vascular anastomosis and consequently establish a more stable cervical heterotopic heart transplantation model in mice. Methods C57BL/6 male mice (6~8 weeks old, weighing 20~24 g) were categorized into control (conventional cuff technique) and experimental groups (our "Anchoring Node" technique). Time for each surgical step, frequencies of vascular everting and vascular trimming, and the reasons for failure were recorded and compared between the 2 groups. Postoperative survival of heart allograft was determined by daily observation and touching, and the mice with the survival time >48 h were considered as successful model establishment. On the 7th and 14th days after surgery, HE staining was used to observe the pathologic changes in the vascular tissues at anastomosis. The expression of troponin T (cTnT) in the heart on the 7th day was detected with immunofluorescence assay. Results ① In the 25 hearts from each group, 2 hearts from the experimental group and 8 from the control group failed, and the survival rate of heart allografts was 92% and 68%, respectively. In the experimental group, arterial and venous everting occurred at an average of 1.16 times, with an average frequency of trimming of 0.04 times, while in the control group, arterial and venous everting was 2.00 and 2.28 times, respectively, with an average frequency of trimming of 0.21 and 0.46 times, respectively. ② Significant differences were observed in the overall duration for cervical heterotopic heart transplantation (77.22±3.82 vs 87.49±8.01 min), vascular separation plus cannulation (30.06±2.68 vs 36.50±6.67 min), and cervical anastomosis (7.31±1.08 vs 12.34±2.58 min) between the experimental and control groups (all P < 0.05). ③HE staining displayed that vascular patency was observed in the experimental group on the 7th and 14th days after surgery. ④cTnT staining indicated no massive myocardial necrosis was seen in both groups. Conclusion Based on conventional cuff technique for mouse cervical heterotopic heart transplantation, our modified "Anchoring Node" technique ensures the stability and efficiency of one-man microscopic operation with controllable quality, with the advantages of longer postoperative survival of heart allograft, high patency rate of anastomotic vessels, good cardiac function, and fewer postoperative complications.

Keywords

• heart transplantation
• cuff technique
• mice
• model