Morphologic chages in the pulmonary tissue of laboratory rats in case of subcutaneous development of the solid form of experimental ovarian tumor

Transplanted organotropic strain of the ovarian tumor of rats is able to develop in different forms depending on technique of transplantation. In case of subcutaneous introduction of the tumor cells it develops in the form of solid tumor node. In case of intraperitoneal introduction of the tumor cells it develops in the form of ascites. In case of intravenous introduction of the tumor cells it develops in the form of numerous pulmonary metastases. We studied morphologic changes in rat's lungs in case of subcutaneous development of the solid form of experimental ovarian tumor. 

Actuality. Transplanted organotropic strain of the ovarian tumor of rats is able to develop in different forms depending on technique of transplantation. In case of subcutaneous introduction of the tumor cells it develops in the form of solid tumor node. In case of intraperitoneal introduction of the tumor cells it develops in the form of ascites. In case of intravenous introduction of the tumor cells it develops in the form of numerous pulmonary metastases. We studied morphologic changes in rat's lungs in case of subcutaneous development of the solid form of experimental ovarian tumor.

Methods. For our investigation we used ten laboratory rats (males) at the age of three months. The animals were divided into two groups (each of the groups was made up of five rats). The group №1 was control, it included intact rats. The group №2 included the rats which underwent the subcutaneous transplantation of the ovarian tumor strain.

By the tenth day after transplantation the tumor nodes in the rats of the group №2 was one centimeters in diameter. On that day the animals of both groups were killed. Lungs and tumor tissue were extracted and fixed in solution of formalin. Paraffin sections were stained with haematoxylin-eosin. Histologic specimens were observed under light microscope.

Discussion. In histologic specimens the tumor tissue is characterized by mosaic structure because of the fact that its different zones considerably vary in structure. Some of the zones are structurally preserved, they consist of densely arranged malignant cells the boundaries of which are not prominent. Closed-face nuclei of the cells are rounded, oval and irregular in shape, their diameter is 6,04±0,25 micrometers.

Between clusters of malignant cells there are layers of homogeneous anucleate substance. Some of such zones are considerable in size. They contain thin-walled vessels lined by flattened endothelium containing closed-face elongated nuclei. The vessels contain formed elements of blood and cast-off collapsing malignant cells.

The zones of the preserved tumor tissue are continuous with zones which are made up of vacuolated malignant cells. Closed- face nuclei of the cells are rounded, oval and polygonal in shape, their diameter is 7,06±0,19 micrometers.

Above described zones of the tumor tissue abruptly transit to the zones which are characterized by loose arrangement of malignant cells. The cells contain a larger amount of cytoplasm, the latter is less intensely stainable, vacuolated and granular in structure, boundaries of the cells are indistinguishable. Their closed-face nuclei are rounded, oval and irregular in shape. Diameter of the nuclei is less than that of the cells in the above described zones of the tumor (4,52±0,17 micrometers). Among the malignant cells here one can find anucleate ones. There are also small cavities remained in places of entirely destroyed cells. Tumor tissue in such zones is penetrated by vessels containing formed elements of blood and numerous cast-off malignant cells. Some zones of the tumor are made up of eosinophilic lumps and disorderly scattered fragments of the malignant cell nuclei. Within those zones there are large cavities containing separate fragments of the eosinophilic lumps.

There are also some cavities which are filled with homogeneous colloid-like substance.

External surface of the lungs of control rats (group №1) are covered by serous tunic which consists of flattened mesothelium and subepithelial connective tissue layer. Mesothelium is 4,13±0,19 micrometers in thickness, its cells contain closed-face elongated nuclei. The subepithelial connective tissue layer is penetrated by numerous capillaries, it is made up of a large amount of cellular elements containing oval nuclei and wavy fibres oriented parallel to the pulmonary surface. Serous tunic of the lungs is 19,2±1,1 micrometers.

The bulk of the pulmonary parenchyma is made up of alveoli between which the bronchi of different size are located. The alveoli are lined by flattened epithelial cells containing elongated nuclei. Alveoli situated in the peripheral parts of lungs do not differ considerably in size from those situated in the central parts. Their diameters are 21,1±1,6 micrometers and 23,63±1,26 micrometers correspondingly.

There isn't prominent difference in density of the arrangement of alveoli in different parts of lungs. In one microscopic visual field the number of alveoli in the peripheral pulmonary parts is 6,73±0,26, and in central pulmonary parts is 7,66±0,33.

Alveoli are detached from one another by means of thin alveolar septa which are penetrated by capillaries. The alveolar septa consist of densely arranged cellular elements and thin connective tissue fibres. The septal cellular elements contain rounded and oval nuclei which have distinguishable nucleoli and masses of chromatin. In the peripheral pulmonary parts the thickness of alveolar septa is 9,75±0,49 micrometers, and in the central pulmonary parts it is 8,73±0,43 micrometers.

Bronchi of any size are followed by blood vessels. Arteries are characterized by presence of well developed smooth muscle of media. Large veins have valves.

The walls of thе bronchi, the luminal diameter of which is eight hundred to one thousand micrometers, contain cartilage plates which are 54,05±3,06 micrometers in thickness. Chondrocytes of the cartilage are densely arranged, they are oval and irregular in shape, and they have conspicuous boundaries. Diameter of the cartilaginous cells is 15,44±0,8 micrometers. Oval and rounded nuclei of chondrocytes are 5,38±0,21 micrometers in diameter, they contain distinguishable nuclei and masses of chromatin.

Mucous tunic of the bronchi forms folds which consist of epithelium and lamina propria. In those bronchi which are eight hundred to one thousand micrometers in diameter the height of folds is 62,01±3,01 micrometers. The ratio of the luminal diameter and height of folds is 1 / 0,068, i.e. the folds overlap slight part of the bronchial lumen, this fact is obviously caused by presence of thick cartilage plates preventing contraction. Towards the smallest bronchi the above mentioned ration gradually decreases because the folds overlap more and more part of the bronchial lumen. In the bronchi which are six hundred and fifty to seven hundred and fifty micrometers in diameter the height of folds is 103,89±5,09 micrometers, and the ratio of the luminal diameter and height of folds is 1 / 0,15. In the bronchi which are three hundred and fifty to four hundred and fifty micrometers in diameter the height of folds is 60,38±3,01 micrometers and the ratio is 1 / 0,2. In the bronchi which are two hundred to two hundred and fifty micrometers in diameter the height of folds is 64,35±3,2 micrometers, and the ratio is 1 / 0,39. In the bronchi which are eighty to one hundred micrometers in diameter the height of folds is 39,25±1,9 micrometers, and the ratio is 1 / 0,39.

Inner surface of bronchi is lined by pseudostratified columnar epithelium. Closed-face oval nuclei of the epithelial cells are centrally and distally located. Boundaries of the cells are invisible, basal membrane is indistinct. Towards the smallest bronchi the size of the epithelial cells decreases due to lessening of specific volume of their cytoplasm. In the bronchi which are eight hundred to one thousand micrometers in diameter the height of epithelium is 27,69±1,26 micrometers. In the bronchi which are six hundred and fifty to seven hundred and fifty micrometers in diameter the height of epithelium is 20,36±0,86 micrometers. In the bronchi which are three hundred and fifty to four hundred and fifty micrometers in diameter the height of epithelium is 15,56±0,53 micrometers. In the bronchi which are two hundred to two hundred and fifty micrometers in diameter the height of epithelium is 13,33±0,64 micrometers. The bronchi which are eighty to one hundred micrometers in diameter the height of epithelium is 10,8±0,5 micrometers.

Just under the epithelium the mucosal lamina propria is situated. It is made up of numerous cells containing different-shaped well stainable nuclei, and thin connective tissue fibres.

Bronchial wall contains a layer of smooth muscle. The evenness of muscle in the bronchial wall increases as the bronchi become smaller. In the bronchi which are eight hundred to one thousand micrometers in diameter the thickness of smooth muscle layer is 73,0±3,6 micrometers. In the bronchi which are six hundred and fifty to seven hundred and fifty micrometers in diameter the thickness of smooth muscle layer is 41,65±2,0 micrometers. In the bronchi which are three hundred and fifty to four hundred and fifty micrometers in diameter the thickness of smooth muscle layer is 21,72±1,08 micrometers. In the bronchi which are two hundred to two hundred and fifty micrometers in diameter the thickness of smooth muscle layer is 17,94±0,8 micrometers. In the bronchi which are eighty to one hundred micrometers in diameter the thickness of smooth muscle layer is 7,89±0,3 micrometers.

Bronchial adventitia is made up of numerous cells containing well stainable rounded and oval nuclei, and of thin differently directed fibres. Adventitious connective tissue is gradually continuous with that of adjacent alveolar septa and with adventitia of vessels that's why the boundaries of bronchial adventitia is not prominent.

Bronchial wall contains lymphatic nodules.

Lungs of the rats of the group №2 are characterized by presence of singly arranged malignant cells and not numerous metastases, the latter are not more than one hundred and twenty micrometers in diameter. Tumor nodules are found both in the alveolar lumens and within the alveolar septa.

In the alveolar lumens the malignant cells may be singly arranged (such cells are rounded and oval in shape) and may be arranged in groups filling the whole alveolar lumen (such cells are mainly polyhedral). In any case the cells have prominent boundaries and granular cytoplm. Their rounded, oval, and beanshaped nuclei have distinct karyolemma and masses of chromatin.

In the alveolar lumens one can find collapsing malignant cells among which there are those containing vacuolated cytoplasm, pyknotic nuclei. There are also small cavities remained in places of entire destruction of malignant cells. Some alveoles are filled with anhistic substance within which fragments of nuclei are scattered.

Within alveolar septa the malignant cells are arranged in different-sized groups. In small tumor nodules the rounded and oval cells have distinct boundaries, granular slightly stainable cytoplasm. Their rounded and oval nuclei have distinct karyolemma. In larger metastases the tumor cells are polyhedral in shape, their cytoplasm is stainable more intensevly. Nuclei of many of the cells are closed-face. In small metastases (which are not more than fifty micrometers in size) the tumor cells are 12,36±0,44 micrometers in diameter, the diameter of their nuclei is 4,84±0,14 micrometers. In large metastases (which are about one hundred and twenty micrometers in diameter) the tumor cells are 10,41±0,31 micrometers in diameter, the diameter of their nuclei are 10,41±0,31 micrometers.

Pulmonary tissue located between metastases doesn't show any changes.

Conclusion. Subcutaneous transplantation of the experimental solid tumor of the ovary causes the development of numerous metastases in the lungs.

 

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Year: 2016
City: Almaty
Category: Medicine
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