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Improve the procedure of heart transplantation in mice and summarize the previous experience

Objective 
To explore a modified method of constructing a heart transplantation model of mice and summarize the previous experience, in order to provide a more stable and reliable animal model for basic and clinical researches of organ transplantation. 
 
 
Methods 
We adopted 8-week-old inbred strain of BALB/C and C57BL/6 male mice with no specific pathogen infection. Forty BALB/C mice were used as heart donor and 40 C57BL/6 mice as heart recipient. They were divided into traditional surgery group and modified surgery group randomly and each had 20 pairs mice. Recipients were fasting for 12 hours before the procedure but allowed to intake water. In traditonal surgery group, we adopted intraperitoneal injection of narcotic and continuous suture method to anastomose blood vessel, pulmonary artery was divided at the artery crotch, and the donor heart was covered with gauze soaking in 4 ℃ isotonic sodium chloride solution. Specific improvements in modified surgery group were as follows: adopting inhalation anesthesia, prolonging and trimming the pulmonary artery, donor heart was sustained in ice pack, the method of vascular anastomosis was improved, rewarming in incubator, postoperative rehydration with 5% glucose normal saline, anti-infection with cefazolin and analgesia with buprenorph and so on. We used Student′s t test to compare the diffierences of anastomosis time, graft cardiac rebeating time, surgical time and anesthesia recovery time between two groups. We used chi-square test to compare the diffierences of postoperative survival of mice and grafts between two groups. Difference was statistically significant when P<0.05. 
 
 
Results 
Traditional surgery group: 15 succeed, 5 failed and successful rate was 75%; modified srugery group: 17 succeed, 3 failed and successful rate was 85% (χ2=0.625, P>0.05). The time required for heart resuscitation and the time for anesthesia recovery between traditional surgery group and modified surgery group were (2.9±0.4) min and (1.4±0.3) min, (43.8±6.4) min and (3.2±0.7) min respectively, both of which had statistics significance (t=12.96, 27.19, P all <0.05). 
 
 
Conclusions 
The modified method of heart transplantation is stable and reliable. The operation time and graft cardiac rebeating time are shortened overall. The modified mice model is worth to use widely. 
 
 
Key words: 
Mice; Heart transplantation; Abdomen; Animal model; Modified measure