扫描电镜揭示家兔心包的结构特点及其心房肽转运意义

Structural feacture and functional significance for transporting atrial natriuretic peptide of rabbit pericardium revealed by scanning electron microscope

采用常规和NaOH消蚀/叔丁醇冻结干燥法,应用扫描电镜观察家兔心包腔面的结构特征,为心包液中心房肽的来源、去向及其意义,提供形态学依据。结果显示:脏层心包表面可见完整的大型膜包分泌颗粒(1μm^4μm);壁层心包表面,可见立方形和扁平形两种上皮细胞;在相邻的3个立方细胞之间,存在三角形的孔隙(5μm);还可见到乳斑样结构。在NaOH消蚀处理的心包,可见成簇筛孔(10μm^20μm)组成的筛斑,另有网状纤维把筛孔分割成许多网眼(0.5μm^2μm)。这些结构特征提示,心房颗粒或心房肽可能通过心外膜直接进入心包腔,再由心包膜的淋巴管吸收、转运而发挥作用。

We observed the structural feature of luminal surface of the rabbit pericardium by scanning electron microscopy （SEM）with conventional and NaOH-maceration / t-butyl alcohol freeze-drying methods, in order to offer the morphological evidences for the how-to-come, the how-to-go and the significance of atrial natriuretic peptide（ANP）in the pericardial fluid. The result shows that the intact big secretory granules （1μm- 4μm） coated with membrane could be seen on the surface of the visceral pericardium. And on the surface of the parietal pericardium exist two types of mesothelial cells： the cuboidal and the squamous. Among three adjacent cuboidal cells exist a triangular pore （5μ） . In addition, the milk spots-like structure could be also seen on the parietal pericardium. On the surface of the pericardium macerated with NaOH we found that the maculae cribrosae was composed of the clustered cribriform foramina （10μm - 20μm） which was divided into many meshes （0.5μm - 2μm） by the reticular fibers. These structural features indicate that atrial secretory granules or ANP could seem to directly enter the pericardial cavity through the epicardium, then be absorbed and transported by the lymphatic vessel of the pericardium.