应用活体荧光技术观察LDLR~(-/-)小鼠血管损伤后初期病变形成的动态变化

目的应用活体荧光技术,研究血管损伤后初期病变形成的动态变化。方法 112只雄性LDLR-/-小鼠随机分成14组,每组8只。将绿色荧光蛋白表达而低密度脂蛋白受体敲除(GFP+/LDLR-/-)小鼠的骨髓移植到LDLR-/-小鼠中,行血管损伤手术。从术后第1天至14天,麻醉小鼠,在荧光显微镜下直接观察股动脉血管病变变化的动态状况。结果术后第1天即见血管内大量荧光细胞随血液高速循环,术后第3天出现血液中的荧光细胞呈点状粘附于血管内壁,术后第6天,在血管内壁荧光细胞粘附的部位,外膜组织开始明显增生,增生的外膜组织中可见荧光细胞,此时血管内壁的病变呈不规则的片状分布。术后第9天,血管外纤维组织显著增生,并见大量的荧光细胞,同时可见外膜组织中有血液流动的新生营养血管。至病变第14天,受损血管的病变程度在以前的基础上继续增加,病变部位血管内膜上粘附聚集大量的荧光细胞,形成内衬而附着于血管内膜。结论血管损伤后的初期病变存在着由血管内到外的发展趋势。病变的形成与循环血中骨髓来源的干细胞在内膜部位粘附和聚集具有紧密的联系,血管内膜的病变对血管外纤维组织的增生具有明显的影响。

Fluorescence microscopic observation of the dynamics of early lesion formation after vascular injury in LDLR -/- mice in vivo

Objective To study the early dynamics of lesion formation after vascular injury in LDLR-/- mice by in vivo fluorescence microscopy. Methods One hundred and twelve male LDLR -/- mice （18-22 weeks of age） were randomly divided into 14 groups （8 mice in each group）. The mice were subjected to bone marrow cell transplantation from GFP -/LDLR -/- mice. After 4 weeks, a polyethylene cuff was implanted around the right femoral artery to induce vascular injury. The lesion formation was observed on the injured femoral artery from 1 to 14 days after vascular injury. Results At the 1st day after cuff placement, a markedly large number of GFP positive cells were clearly observed in high-speed blood flow. At the 3rd day after the vascular injury, GFP positive cells accumulated in the inner vascular wall and formed punctate lesions. At the 6th day after the vascular injury, GFP positive cells in the inner vascular wall formed irregular flakes, and a small amount of the adventitia tissue proliferated, corresponding to the inner lesion area. At the 9th day after the vas-cular injury, the adventitia tissue was obviously proliferated and a large number of GFP positive cells embeded. The vasa vasorum were clearly seen running in the adventitial layer. At the 14th day after the vascular injury, the adventitia tissue proliferated considerably with largely GFP positive ceils and could not be observed in the lesion through adventitia. After stripping the outer tissue of vessel wall, the fluorescent lesion formed by GFP positive cells was clearly lining in the intima area. Conclusions The results of our study demonstrate that the vascular remodeling lesion in the early stage in LDLR -/- mice has a trend of ＂inside out＂. The dynamics of lesions has a close correlation with bone marrow-derived cells that circulating in the blood flow. There is distinct influence of the vascular lesions on extravascular fibrosis.