Holzhausen H J, Schreiber D
Exp Pathol (Jena). 1977;13(1):20-31.
The views on the histogenesis of experimental heart tumours in rats are controversal. Up to now electron microscopic investigations on early tumour stages are lacking. In this study ultrastructural findings of 4 early stages of heart neoplasms in the left ventricle of BD-IX rats are reported. Material and methods. BD-IX rats received repeated intravenous injections of methylnitrosourea in a dosage of 20 mg/kg body weight. After averagely 9 months the animals were killed by ether anesthesia. Sections of the heart were fixed in solution according to Karlsson and Schultz (1965). In order to discover early stages of tumours light microscopic examinations were carried out on heart sections. Afterwards the small tumour-containing tissue samples were postfixed in 1% OsO4, embedded in durcupan, and double contrasted with uranyl acetate and lead citrate. Results. Light microscopy (semithin sections): Beneath an endothelium-like cell layer an area of parallel to each other arranged spindle-shaped tumour cells with usually hyperchromatic nuclei was found. Some cells were larger and contained pale nuclei. Electron microscopy: The spindle-shaped neoplastic cells with irregular nuclei are loosely arranged. Most of the cells were surrounded by a basement membrane. In the extracellular space abundant thin cell processes and collagen fibers were demonstrable. The tumours contained characteristic bundles of cell processes as well as single processes which enveloped a virtual point of the space. Some large and widely undifferentiated tumour cells had stump-like thick processes. In the area of trabecular muscle neoplastic cells of an apparently mesenchymal origin were present. The ultrastructural findings are discussed regarding the histogenesis of the small heart tumours in the rats. They probably developed from neoplastic Schwann cells but an additional mesenchymal component seems to be engaged. Further studies are necessary to clarify the significance of both components and their relations in the experimental heart tumours.
关于大鼠实验性心脏肿瘤的组织发生学观点存在争议。到目前为止，缺乏对肿瘤早期阶段的电子显微镜研究。本研究报告了BD-IX大鼠左心室4个心脏肿瘤早期阶段的超微结构发现。材料与方法。BD-IX大鼠接受重复静脉注射甲基亚硝基脲，剂量为20mg/kg体重。平均9个月后，用乙醚麻醉处死动物。心脏切片按照卡尔森和舒尔茨（1965年）的方法固定在溶液中。为了发现肿瘤的早期阶段，对心脏切片进行了光镜检查。之后，将含有小肿瘤的组织样本用1%的四氧化锇后固定，包埋在杜尔库潘中，并用醋酸铀和柠檬酸铅进行双重对比。结果。光镜检查（半薄切片）：在内皮样细胞层下方，发现了一层相互平行排列的梭形肿瘤细胞区域，其细胞核通常染色过深。一些细胞较大，含有淡染的细胞核。电子显微镜检查：细胞核不规则的梭形肿瘤细胞排列松散。大多数细胞被基底膜包围。在细胞外空间可显示出丰富的细细胞突起和胶原纤维。肿瘤含有特征性的细胞突起束以及包裹着空间虚拟点的单个突起。一些大的、未分化的肿瘤细胞有树桩样的粗突起。在小梁肌区域存在明显起源于间充质的肿瘤细胞。就大鼠小心脏肿瘤的组织发生学对超微结构发现进行了讨论。它们可能起源于肿瘤性雪旺细胞，但似乎还有一个间充质成分参与其中。需要进一步研究以阐明这两个成分在实验性心脏肿瘤中的意义及其关系。
