Actuality. Experimental Ehrlch's tumor is able to develop in the organism of mice of all breeds. It is characterized by fast growth and high degree of malignancy. Due to those facts it is widely used for investigation of antitumor drugs. But microscopic structure of this tumor remains unstudied. Information which we could discover in the available literature was very superficial. Hence we had for an object to investigate microscopic structure of the ascitic and solid forms of the experimental Ehrlich's tumor. Methods. For our investigation we used twenty sexually mature males of laboratory mice, the average body weight of which was about thirty-five grammes. All the animals were housed in the condition of vivarium. We formed two experimental groups of mice (group number one and group number two) each of the groups included ten animals.
Mice of the group number one were subjected to intraperitoneal transplantation of the cells of Ehrlich's tumor for the development of ascitic form of the tumor. Animals of this group were killed on the eleventh day after the beginning of the experiment. Abdominal cavity was dissected and the ascites was collected in a graduated cylinder for determination of its volume. Then with the help of Gorjaev's count chamber we determined the number of the tumor cells in one milliliter of the ascites, and determined the number of the tumor cells in the whole ascites. Mice of the group number two were subjected to subcutaneous (in femoral region) transplantation of the cells of Ehrich's tumor for the development of solid form of the tumor. Animals of this group were killed on the twenty-third day after the beginning of the experiment. Developed solid tumor was extracted, weighed and its three perpendicular diameters were measured. Volume of the tumor was calculated in accordance with the formula of the volume of ellipsoid:
Experimental Ehrlch's tumor is able to develop in the organism of mice of all breeds. It is characterized by fast growth and high degree of malignancy. Due to those facts it is widely used for investigation of antitumor drugs. But microscopic structure of this tumor remains unstudied. Information which we could discover in the available literature was very superficial. Hence we had for an object to investigate microscopic structure of the ascitic and solid forms of the experimental Ehrlich's tumor.
V = 4/3пabc
π - 3,14; a, b, c - radii of tumor.
Density of the tumor was calculated in accordance with the following formula: ρ = m/V
m - weight of tumor; V- volume of tumor.
Pieces of tumors were fixed in solution of formalin. Paraffin sections were stained with haematoxylin-eosin. Histologic specimens were observed under light microscope.
Discussion. In the mice of the experimental group number one the volume of ascites varied from seven and a half millilitres till nineteen milliliters (average was thirteen and a half milliliters). The number of the tumor cells in one milliliter of ascites varied from 33312500 till 78875000 (average was 58133928,57). We did not detect any prominent correlation between the volume of the ascites and concentration of the tumor cells. In some cases the ascites was serous, in the other cases it was hemorrhagic. Hemorrhagic ascites was accompanied by conspicuous paleness of the liver.
In the mice of the experimental group number two the weight of the solid tumor varied from 1350 milligrammes till 2600 milligrammes (average was 2022,22 miligrammes). Volume of the tumor varied from 1292,63 square millimetres till 2455, 48 square millimetres (average was 2062,1 square millimetres). Density of the tumor varied from 0,8 mg/mm3 till 1,2 mg/mm3 (average was 1,0 mg/mm3).
Microscopic investigation shows mixed structure of the solid Ehrlich's tumor. But there are some morphologic regularities. Tissue of the solid tumor is made up of several layers. The most superficial layer (18,33±0,7 micrometers in thickness) consists of flattened elongated cells oriented along the tumor surface. The tumor cells are closely apposed that's why their boundaries are not visible. Their oval elongated nuclei (small diameter of which is 2,92±0,1 micrometers) are densely stained with hematoxylin.
Deeper located layer of the tumor is made up of more loosely arranged cells. Densely stained nuclei of the cells are characterized by rounded, oval polyhedral and irregular shape. Diameter of the cells of this layer on the average is 9,83±0,3 micrometers, and diameter of their nuclei is 6,4±0,3 micrometers. This tumor layer contains blood vessels the wall of which is gradually destroyed by the tumor cells.
This tumor layer is gradually continuous with the deeper located layer in which the cells are arranged much looser. Boundaries of the most cells are not visible. Average diameter of the nuclei increases till 7,74±0,31 micrometers though the diameter of the largest nuclei achieves 14,0 micrometers. Nuclei of the tumor cells are rounded or oval in shape. They contain prominent karyolemma distinct nucleoli and masses of chromatin. The number of nucleoli varies from one to five. Cytoplasm of many tumor cells contains vacuoles. This tumor layer is penetrated by thin-walled blood vessels inner surface of which is lined by flattened endothelial cells with elongated poorly stained nuclei. These blood vessels are gradually destroyed by surrounding tumor cells. Formed elements of blood leave the destroyed vessels and penetrate between the tumor cells.
Tissue of the tumor also contains zones which are made up of loosely arranged densely stained cell nuclei (the nuclei are 5,15±0,23 micrometers in diameter) surrounded by demolished cytoplasm looking like thin interlacing threads. Some of the nuclei are picnotic. These zones contain small blood vessels inner surface of which is lined by endothelial cells with rather large oval nuclei. Most of the endotheliocytes have densely stained nuclei, but in some cases the nuclei are characterized by prominent karyolemma and distinct mass of chromatin.
The deepest part of the tumor is filled by necrotizing tissue which is made up of fragments of destroyed tumor cells. Within this necrotic zone one can discover islets that structurally resemble above mentioned layers. Most of such islets are located around preserved blood vessels.
Conclusions. Ascitic form of Ehrlch's tumor is characterized by presence of numerous malignant cells. Solid tumor is characterized by lamellar structure.
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