The Effect Of Amlodipine Maleate On Rabbit's Autologous Vein Graft Intimal Hyperplasia

Objective:To observe the inhibition effect of amlodipine maleate on rabbit autologous vein graft intimal hyperplasia and to explore its mechanism.Methods:Chose 36 healthy adult New Zealand white rabbits, half male and half female, weighing 2.0 ~ 2.5kg. They were randomly divided into two groups, control group (n=18) and amlodipine experimental group (n=18), each 18 animals. Autologous vein graft model was established for each animal, took the right external jugular vein and grafted it into the ipsilateral common carotid artery. In amlodipine experimental group each was gavaged by amlodipine 2.5mg / only / day dissolved in 0.9% sodium chloride after the first day of its surgery, while control group were gavaged by the same amount of 0.9% sodium chloride to do blank control. The experiment was carryed on until samples were taken. Rabbits were given haparin sodium 25mg intramuscular injection for anticoagulation for 3 days. In the second and fourth week after the surgery, 9 rabbits were harvested in both groups each time, harvesting and vein graft. Hematoxylin-eosin (HE) staining and observation of histology morphology, to measure intima media thickness, to detect proliferating cell nuclear antigen (PCNA) and the positive cell ratio of basic fibroblast growth factor (bFGF) by immunohistochemistry, and to disclose the level of VSMC apoptosis in samples by TUNEL assay.Results:1. Gross observation All the animals survived after models were made. Two saphenous vein by pass were clogged when samples were drawn. The immediate patency rate was 100% after the vein graft, and that was 100% when samples were drawn.2. Histology morphologySmooth muscle cell volume was found to be increased by HE staining light microscopy in control group after two weeks of transplantation, and secretion smooth muscle cells increased; A large number of intimal smooth muscle cells were visible after 4 weeks of surgery, medial smooth muscle cell interstitials and collagen fibers increased significantly. No significant increase in smooth muscle cells in amlodipine experimental group after 2 weeks of surgery; a slight increase in smooth muscle cells after 4 weeks of surgery, and an increase in secretory smooth muscle cells.3. Immunohistochemical gene expressionAfter 2 weeks of surgery, the positive cell percentage of intimal PCNA in control group were respectively (38.05±2.40)%, which increased significantly compared with that of amlodipine experimental group (21.37±2.31)%; After 4 weeks of surgery, the number of positive cells of intimal PCNA in control and amlodipine experimental groups were both reduced, the positive cell percentage of intimal PCNA in control group (57.29±1.35)% were much more than that in amlodipine experimental group(31.70±4.80)% (P<0.05). After 2 weeks of surgery, the positive cell percentage of intimal bFGF in control group were respectively (52.7±7.4) %, which increased significantly compared with that of amlodipine experimental group (45.2±10.1)%; After 4 weeks of surgery, the number of positive cells of intimal bFGF in control and amlodipine experimental groups were both reduced, the positive cell percentage of intimal bFGF in control group (61.6±6.2)% were more than that in amlodipine experimental group(56.4±8.8)% (P<0.05).4. The detect of cell apoptosis in situ by TUNELThe proportion of positive cells in intima (7.45±0.27) % and (3.14±0.32) % after 2 weeks and 4 weeks of vein graft in B group increased significantly than that in control group (4.27±0.18) % and (1.75±0.12) %, the difference was statistically significant(P<0.05). Conclusions:1. Amlodipine can reduce the expression of PCNA and bFGF in vein vascular smooth muscle in the autogenous graft, lower its biological activity, thus inhibit the migration of VSMC.2. Amlodipine can enhance the expression of TUNEL in vein vascular smooth muscle in the autogenous graft, slow rate of vein graft intimal thickening , ease of vascular smooth muscle thickening.