血管活性肽在大鼠血管再狭窄形成中的作用

目的 研究血管活性肽在血管再狭窄形成中的作用。方法 在大鼠主动脉内皮球囊拉伤模型上，采用放射免疫法测定大鼠血浆及主动脉组织内皮素（ＥＴ）、降钙素基因相关肽（ＣＧＲＰ）和肾上腺髓质素（Ａdm）含量以及组织中血管紧张素Ⅱ（ＡⅡ）含量，用∧３Ｈ－ＴdＲ掺入法和组织学分析观察血管平滑肌细胞（ＶＳＭＣ）增生以及血管内膜／中膜面积比值。并在培养的ＶＳＭＣ上，采用∧３Ｈ－ＴdＲ掺入法研研究血管活性肽对细胞增生的影响。采用ＲＴ－ＰＣＲ法观察血管活性肽对自发性高血压大鼠（ＳＨＲ）和ＷＫＹ大鼠的主动脉和ＶＳＭＣ高血压相关基因－１（ＨＲＧ－１）表达的影响。结果 术后１０d ,血浆及主动脉ＥＴ达高峰，分别较对照组升高６９％和1２４％（Ｐ＜０．０１）；主动态ＡⅡ含量升高８０％（Ｐ＜０．０１）。应用ＥＴ抗血清或卡托普利可明显抑制血管损伤诱导的ＶＳＭＣ增殖和内膜增厚。血浆和主动脉ＣＧＲＰ水平在术后３d升高６４％和８９％（Ｐ＜０．０１）， 术后１０d血浆和组织Ａdm分别升高１２９％和１０２％（Ｐ＜０．０１）。在体应用ＣＧＲＰ（２５μg/kg）可显著抑制管损伤诱导的ＶＳＭＣ增殖和内膜增厚（抑制率分别为６６％和７９％，Ｐ＜０．０１）。ＥＴ和ＡⅡ抑制血管ＨＲＧ－１表达，激活丝裂素活化蛋白素酶（ＭＡＰＫ）；ＣＧＲＰ和Ａdm诱导ＨＲＧ－１表达，并抑制ＭＡＰＫ活性。结论 ＥＴ和ＡⅡ可促进损伤血管内增殖，而ＣＧＲＰ和Ａdm具有代偿性抗内膜增殖作用。ＥＴ、ＡⅡ、ＣＧＲＰ和Ａdm等血管活性肽可通过调节ＨＲＧ－１表达和ＭＡＰＫ途径以调控ＶＳＭＣ增殖，影响损伤血管狭窄的形成。

Effects of vasoactive peptides on the development of restenosis

OBJECTIVE: To investigate the effects of several vasoactive peptides on the development of restenosis. METHODS: The model of balloon angioplasty to the rat aorta was prepared and used to study the changes of endothelin (ET), angiotensin II (A II), calcitonin gene-related peptide (CGRP) and adrenomedullin (Adm) in the plasma and aorta tissues, with radioimmuno-assay. (3)H-TdR incorporation and intima/media ratio of aortic tissue were measured after angioplasty. In cultured vascular smooth muscle cells, effects of these peptides on the proliferation of VSMC were evaluated with (3)H-TdR incorporation. Effects of these peptides on the expression of hypertension-related gene (HRG-1) in aorta tissue and cultured VSMC from SHR and WKY rats were studied by semi-quantitative RT-PCR. RESULTS: After angioplasty, the levels of ET and A II in the plasma and/or aorta tissue were significantly increased, with VSMC proliferation. On day 10 after angioplasty, the levels of ET in the plasma and tissue were increased by 69% and 124% respectively, compared with the that in the control group (P < 0.01); and the levels of aortic A II were increased by 80% (P < 0.01). Antiserum against ET and angiotensin converting enzyme (ACE) inhibitors could obviously inhibit the proliferation of VSMC and neointima formation. Compared with the sham group on day 3 after angioplasty, the CGRP levels in plasma and aorta tissue were increased by 64% and 89% respectively (P < 0.01); the Adm levels in the plasma and aorta tissue were increased by 129% and 102% respectively (P < 0.01). On day 10, intravenous administration of CGRP significantly inhibited the proliferation of VSMC and neointima formation induced by balloon aortic injury with the inhibitory rate of 66% and 79%, respectively, (P < 0.01). ET and A II attenuated the expression of HRG-1 in the aorta, thus activating mitogen activated protein kinase (MAPK). CGRP and Adm potentiated the expression of HRG-1, thus inhibiting the activity of MAPK. CONCLUSIONS: ET and A II stimulate the proliferation of injured intima, and CGRP and Adm have an anti-hyperplasia effects after angioplasty. That these peptides are suggested to be involved in the regulation of proliferation of VSMC and to affect the developing of vascular restenosis, by means of regulating the expression of HRG-1 and MAPK activities.