Objective: To assess the effect of topical application of 5-fluorouracil (5-FU) on intimal hyperplasia in rabbit vein graft.
Methods: Sixty-four male New Zealand white rabbits, aged 5 months and weighing 2.8-3.0 kg, were randomly divided into group A, B, C, and D (n = 16 rabbits per group). Artery defect model was established by cutting about 1 cm artery from the middle part of the dissociated left common carotid artery. A section about 3 cm was cut from the right external jugular vein, and the harvested vein was inverted and end-to-end anastomosed to the artery defect with 9-0 non-traumatic suture. After anastomosis, the extima of the grafted veins in group A, B, and C was completely wrapped with cotton sheet (12 mm x 30 mm x 1 mm in size) immersed by 5-FU at a concentration of 50.0, 25.0, and 12.5 mg/mL, respectively, and each vein was treated 5 times (1 minute at a time). In group D, the extima of the graft veins was treated with normal saline instead of 5-FU. The grafted veins were obtained 1, 2, 4, and 6 weeks after operation, HE staining and Masson staining were preformed for histological changes of grafted vein wall, proliferating cell nuclear antigen (PCNA) immunohistochemistry staining and TUNEL labeling staining were conducted for proliferation and apoptosis of smooth muscle cell of the grafted vein, and transmission electron microscope observation was performed for cellular ultrastructure.
Results: The HE staining, Masson staining, and PCNA immunohistochemistry staining showed that the thickness of intima in group A and B was obviously less than that in group C and D at 1, 2, 4, and 6 weeks after operation, and the proliferation cells in group A and B were less than that in group C and D at 1, 2, and 4 weeks after operation. The thickness of the intima, the degree of intima hyperplasia, the degree of vessel lumen stenosis of four groups at different time points were as follows: at 1 week after operation, group A [(12.69 +/- 1.68) microm, 0.73 +/- 0.05, 0.025 +/- 0.003], group B [(17.52 +/- 2.01) microm, 0.86 +/- 0.06, 0.027 +/- 0.004], group C [(21.92 +/- 1.85) microm, 1.06 +/- 0.09, 0.036 +/- 0.006] and group D [(26.45 +/- 3.86) microm, 1.18 +/- 0.08, 0.041 +/- 0.005]; at 2 weeks after operation, group A [(24.61 +/- 2.91) microm, 0.86 +/- 0.06, 0.047 +/- 0.003], group B [(37.28 +/- 2.78) microm, 1.17 +/- 0.09, 0.060 +/- 0.004], group C [(46.52 +/- 2.25) microm, 1.44 +/- 0.08, 0.073 +/- 0.003], and group D [(52.07 +/- 3.29) microm, 1.45 +/- 0.05, 0.081 +/- 0.006]; at 4 weeks after operation, group A [(61.09 +/- 6.84) microm, 1.38 +/- 0.08, 0.106 +/- 0.007], group B [(63.61 +/- 8.25) microm, 1.40 +/- 0.07, 0.107 +/- 0.010], group C [(80.04 +/- 7.65) microm, 1.64 +/- 0.07, 0.129 +/- 0.011], and group D [(84.45 +/- 9.39) microm, 1.68 +/- 0.10, 0.139 +/- 0.014]; at 6 weeks after operation, group A [(65.27 +/- 5.25) microm, 1.46 +/- 0.07, 0.113 +/- 0.005], group B [(65.82 +/- 7.12) microm, 1.45 +/- 0.05, 0.112 +/- 0.011], group C [(84.45 +/- 9.39) microm, 1.69 +/- 0.09, 0.135 +/- 0.007], and group D [(87.27 +/- 8.96) microm, 1.76 +/- 0.05, 0.140 +/- 0.012]. Group A and B were inferior to group C and D in terms of the above three parameters and cell proliferation index 1, 2 and 4 weeks after operation (P < 0.05). Group A and B were superior to group C and D in terms of cell apoptosis index of intima and media 1 and 2 weeks after operation (P < 0.05). Transmission electron microscope observation showed that the synthetic cell organelles such as rough endoplasmic reticulum, golgi apparatus, and ribosome in group A and B were obviously less than those in group C and D (P < 0.05).
Conclusion: Topical application of 5-FU can effectively inhibit intima hyperplasia of the vein grafts.