Modification of Athferoma by cytokin gene transfer

我们建立大鼠双球囊损伤模型，采用免疫组织化学和RT-PCR方法对增厚的新生内膜进行研究。第一次球囊损伤大鼠左颈总动脉14天后，在同一部位进行第二次球囊损伤。采用单球囊和双球囊损伤后14天的组织化学切片计算内膜/内侧（I/M）面积比，作为新内膜形成的指标，并进行免疫组织化学染色。还从一些动脉中纯化了总RNA，并使用RT-PCR方法估计了一些细胞外基质（ECM）和与ECM代谢相关的细胞因子受体的mRNA表达。大鼠双球囊损伤模型（II）的I/M比（1.84±0.62(mean±SE, n=5)）显著高于单球囊损伤模型(I)(1.30±0.19,n=10) （p<0.05）。在平滑肌细胞的表型上，α-actin染色显示II型的新生内膜以收缩形式多于合成形式，而I型的新生内膜以合成形式多于收缩形式。II的内膜被层粘连蛋白和纤维连接蛋白强烈染色，而I的内膜仅被弱染色。与这些数据一致，层粘连蛋白和纤维连接蛋白mrna在II的新生内膜中显著表达。I型和II型的新生内膜也同样呈PDGF （α和β）和TGF-β （I型和II型）受体阳性。这些结果表明：ECM的积累，特别是层粘连蛋白和纤维连接蛋白的积累，是双球囊损伤模型的特征；该模型中ECM的显著积累是由PDGF或TGF-β信号通路以外的机制引起的；该模型与ptca后再狭窄病变相似，为其研究提供了关键。

We developed a rat double-balloon injury model and studied the thickened neointima using immunohistochemical and RT-PCR methods. Fourteen days after the first balloon injury of the rat left common carotid artery, a second balloon injury was inflicted in the same place. Histochemical sections taken 14 days after the single- and double-balloon injuries were used for calculating intimal/medial (I/M) area ratios, as an indicator of neointimal formation, and were subjected to immunohistochemical staining. Total RNA was also purified from some arteries and mRNA expression of some extracellular matrices (ECM) and cytokine receptors related to ECM metabolism was estimated using the RT-PCR method. The I/M ratio in the rat double-balloon injury model (II) (1.84±0.62(mean±SE, n=5)) was significantly (p<0.05) higher than that in the single-balloon injury model (I) (1.30±0.19, n=10). The cell number per neointimal area was less in II than in I. As for the phenotype of smooth muscle cells, α-actin staining showed that the neointima of II consisted of more contractile form than synthetic, whereas that of I consisted of more synthetic form than contractile. The neointima of II was strongly stained with laminin and fibronectin, but that of I was stained only weakly. Consistent with these data, laminin and fibronectin mRNAs were markedly expressed in the neointima of II. Neointimas of both I and II were also stained positively with PDGF (α and β) and TGF-β (types I and II) receptors to the same extent. These results show: that ECM accumulation, particularly of laminin and fibronectin, characterizes the double-balloon injury model; that the marked accumulation of ECM in this model is due to a mechanism other than the PDGF or TGF-β signalling pathway; and that this model resembles the lesion of post-PTCA re-stenosis, and therefore provides the key for its investigation.