ObjectiveTo investigate the expression of extracellular signalregulated kinase (ERK) and p38 mitogenactivated protein kinase （p38 MAPK） in autogenous vein grafts during vascular remodeling.MethodsAn autogenous vein graft model was established by transplanting the right jugular vein to infrarenal abdominal aorta in 80 Wistar rats. Vein graft samples were harvested 6 hours, 24 hours, 3 days, 7 days, 2 weeks, 4 weeks, 6 weeks and 8 weeks after surgery. Gene expression of ERK and p38 MAPK was measured by reverse transcriptionPCR. Western blot was used to detect the expression of protein products and phosphorylation protein products of ERK and p38 MAPK. Apoptosis of vascular smooth muscle cells (VSMCs) was determined by TUNEL. Proliferating cell nuclear antigen(PCNA) of VSMCs also was studied.ResultsThe expression of ERK1 mRNA and p38 MAPK mRNA increased considerably after surgery. ERK1 mRNA reached the peak on the 7th day 〔（33.2±14.2）%, P＜0.01〕, but p38 MAPK mRNA reached the peak on the second week after surgery 〔(58.8±26.2）%, P＜0.01〕. The expression of ERK1/2 detected by western blot reached the peak during 1 to 2 weeks and decreased gradually to normal level 6 weeks after surgery. The expression of p38 MAPK reached the peak during 2 to 4 weeks and decreased to 1/4 to 1/2fold 8 weeks after surgery. There was a positive relationship between ERK1 and PCNA(r=0.759 6，P＜0.01) and a positive relationship between p38 MAPK and apoptosis(r=0.892 2，P＜0.01). ConclusionActivation of MAPK system exists in autogenous vein grafts and it may become a new target for the therapy of stenosis after vein grafts.
Objective To investigate the influence of RNA interference targeting c-Jun gene on the proliferation of rat vascular smooth muscle cells (VSMCs). Methods The experiment was performed with c-Jun siRNA （c-Jun siRNA group）, control reverse sequence siRNA (control siRNA group) or no siRNA (control group). VSMCs were transfected with siRNA targeting c-Jun gene by liposome. Effects of c-Jun siRNA on mRNA and protein expressions of c-Jun were examined by RT-PCR analysis and Western blot respectively. MTT test and 3H-TdR incorporation were used to detect VSMCs proliferation. Cell cycle analysis of VSMCs in vitro was determined by flow cytometer. Results The expression levels of mRNA and protein of c-Jun in c-Jun siRNA group were significantly lower than those in control group （P＜0.05， P＜0.01). There was no significant difference between control group and control siRNA group （Pgt;0.05）. Proliferation activity of VSMCs decreased significantly in c-Jun siRNA group compared with that in control group （P＜0.05） and VSMCs was blocked in the G0/G1 phase of cell cycle significantly （P＜0.05）. There was no significant difference between control group and control siRNA group （Pgt;0.05）. Conclusion c-Jun gene silenced by RNA interference can inhibit VSMCs proliferation effectively in vitro.
Objective To investigate the effect of survivin antisense oligodeoxyribonucleotides (survivin ASODNs) on intimal hyperplasia (IH) in vein graft in rats. Methods Autogenous vein graft models were established in 60 Wistar rats by transplanting the interior jugular vein to the common jugular artery using microsurgical technique. The rats were divided into 5 groups according to random digits table, including survivin ASODNs 50 μg group and 200 μg group, scramble ODNs 200 μg group (ODNs group）, Lipofectin+pluronic group and control group. Vein graft samples were collected on 7 d and 14 d after transplantation, respectively. The degrees of hyperplasia were determined and then compared by histomorphology between different groups. The expression of survivin mRNA was measured by RT-PCR and immunohistochemistry. The relevant protein products were detected by Western blot and immunohistochemistry was also used to detect the expression of PCNA. Apoptosis of VSMC was measured by TUNEL.Results Day 7 and 14 were the days that intimal hyperplasied most in control group, ODNs group and Lipofectin+pluronic group, there was no significant difference among these groups yet (Pgt;0.05). The IH could be suppressed by locally transfecting 50 μg of survivin ASODNs (P＜0.05), and it showed a better inhibiting effect in 200 μg of survivin ASODNs group (P＜0.05). The expression of survivin mRNA increased significantly in control group. The expressions of both survivin and PCNA in VSMC significantly decreased in survivin ASODNs group (P＜0.05), whereas the positive cells of TUNEL increased significantly (P＜0.05). Conclusion Transfection of survivin ASODNs may inhibit the IH after vein graft through suppressing the hyperplasia and stimulating the apoptosis of VSMC, and inhibiting the expression of survivin.
Objective To investigate the development and significance of the expression of early growth response gene-1 （EGR-1） in autogenous vein graft in rats and detect the role of it in intimal hyperplasia. Methods Autogenous vein graft model was established in 90 Wistar rats, transplanting the right jugular vein to infra renal abdominal aorta by microsurgical technique. The vein graft samples were harvested at hour 1, 2, 6 and 24, day 3, 7,14, 28 and 42 after procedure. Normal vein as control group. Egr-1 mRNA was measured by reverse transcription-PCR and in situ hybridization. Western blot and immunohistochemistry were used to detect the protein expression of Egr-1. Results Intimal hyperplasia reached peak at day 28 after autogenous vein graft surgery. Egr-1 mRNA and Egr-1 protein hadn’t been found in the normal vein. The expressions of Egr-1 mRNA and Egr-1 protein had biphasic changes. By reverse transcription-PCR and in situ hybridization, we found that the level of Egr-1 mRNA rose at 1 hour after graft, the expression of Egr-1 mRNA was (35±7)%. Decline at hour 6， 24 and day 3, the positive rates of Egr-1 mRNA were (8±2)%, (8±6)% and (8±4)% respectively. Reincrease at day 7, a peak at day 28, the positive rate of Egr-1 mRNA was (45±6)% (compared with other phase, P＜0.01). At day 42, the expression of Egr-1 mRNA declined again. Immunohistochemical staining and Western blot revealed Egr-1 protein had expressed at hour 2 early phase, the expression of Egr-1 protein was (30±5)%, and until to hour 6. The level of Egr-1 protein was decrease at hour 24 and day 3, the positive rates were (7±3)% and (7±8)% respectively. A peak at day 28, the positive rate of Egr-1 protein was (40±9)% (compared with other phase, P＜0.01). We found that immu-noreative Egr-1 located vascular smooth muscle cells （VSMCs） and monocytes/macrophages in tunica media at the early phase of day 7 and 14, and in neointimal and medial VSMCs at later phase of day 28. Egr-1 was also present in the endoluminal endothelial cells. Conclusion In autogenous vein graft, Egr-1 plays an important role in the proliferation of VSMCs. Egr-1 may become a new target for the prevention and therapy of intimal hyperplasia, stenosis and emphraxis after vein graft.
ObjectiveTo detect the inhibitory effect of early growth response gene-1 DNA enzyme (EDRz) on proliferation of vascular smooth muscle cell (VSMC) and intimal hyperplasia, and confirm the effect of gene therapy on stenosis and occlusion after vein transplantation. MethodsEDRz was constructed, and autogenous vein graft model was established with Wistar rats, transplanting the right jugular vein to infra renal abdominal aorta by microsurgical technique. EDRz was transfected to the graft veins and the vein graft samples were harvested at hour 1, 2, 6, 24 and on day 3, 7, 14, 28, 42 after grafting, 10 Wistar rats were randomly selected in every time. The expression of EDRz in transfected vein graft was detected by fluorescent microscope. Egr-1 mRNA was measured by reverse transcription-PCR (RT-PCR) and in situ hybridization, respectively. The protein expression of Egr-1 was detected by Western blot and immunohistochemistry, respectively. HE stained vein grafts were observed under microscope. Results① The results of EDRz transfected vein graft: At hour 1 after grafting, EDRz was mainly located in adventitia, tunica media, and partial endothelial cells of vein graft; At hour 2, 6, and 24, EDRz was located in tunica media of vein graft; and on day 7, it was mainly located in intima of vein graft. There wasn’t EDRz in vein grafts on day 14, 28, and 42. ② The results of expression of Egr-1 mRNA: Detection by RT-PCR: At hour 1 after transfecting, the expression of Egr-1 mRNA arrived at the peak, and declined at hour 2, 6, and 24. The expression was tenuity on day 3. Egr-1 mRNA expression was not found on day 7, 14, 28, and 42. The expression of Egr-1 mRNA at hour 1 was significantly higher than that of the other time point (Plt;0.01). The result of in situ hybridization was coincident with RT-PCR. ③ The results of expression of Egr-1 protein: The result of Western blot: There was no expression of Egr-1 protein in normal veins. At hour 2 after grafting, expression of Egr-1 protein was found, and declined at hour 6, 24, and on day 3. There was no expression of Egr-1 protein at hour 1, and on day 7, 14, 28, and 42. The expression of Egr-1 protein at hour 2 was significantly higher than that of the other time point (Plt;0.01). The result of immunohistochemistry was coincident with Western blot. ④The degree of VSMC hyperplasia and intimal thickness were lighter in EDRz transfected vein grafts than that in nottransfected vein grafts contemporarily. ConclusionsEDRz could reduce the expression of Egr-1 in autogenous vein graft, and could effectively restrain VSMC proliferation and intimal hyperplasia, and prevent vascular stenosis and occlusion after vein grafting.