Abstract: Objective Establish a model of rabbit PTFE artificial vascular grafts on infrarenal abdominal aorta and investigate the mechanism of rapamycin inhibiting restenosis. Methods 18 healthy male New Zealand rabbits weighted 2.5~3.0kg were randomly divided into 3 groups and established models of PTFE artificial vascular graft on abdominal aorta. Group A: the grafts accepted no any management; Group B: 0.5ml 20% pluronic F-127 gel was locally applied to the adventitia of the grafts and anastomoses; Group C: 0.5ml 20% pluronic F-127 gel containing 0.5mg rapamycin was locally applied to the adventitia of the grafts and anastomoses. The grafts were acquired one month after the experiment. Histomorphologic methods were used to detect the intima hyperplasia of the specimen. Electronic imaging system was used to measure the thickness of intima and media of the grafts followed by calculating the degree of intima hyperplasia (thickness of intima/thickness of media). α-actin, PCNA and p27kip1 were investigated by using immunohistochemistry. Data were analyzed by using SPSS13.0 statistics software and then were compiled in the form of（ ）. Results 1. One month after the operation, the intima of Group A and B thickened obviously （P＜0.05）in comparison to C. 2. Result of α-actin immunohistochemistry: the hyperplastic intima was marked obviously, which is consistent with the smooth muscle cells of blood vessels. 3. Result of PCNA and p27kip1 immunohistochemistry: both of them were stained in brown in cell nucleus, and expressed in the thickened intima of every group to study the difference. 4. Compared to A and B, the expression of α-actin and PCNA in C were remarkably inhibited（P＜0.05）, while the expression of p27kip1 was remarkably enhanced（P＜0.05）. No significant deviation was found among A and B（P＞0.05）. Conclusion 1. Smearing rapamycin mixed with pluronic F-127 gel on graft adventitia can effectively inhibit the hyperplasia of vascular smooth muscle cells. 2. The mechanism of rapamycin inhibiting restenosis may be related to increase the expression of p27kip1 and inhibition cell generation cycle.

Key words: artificial vascular graft, intima hyperplasia, rapamycin