Morphologic features of the intrapulmonary form of experimental rat's ovarian tumor at different stages of its development

Transplanted organotropic strain of the tumor of rat's ovary 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 tissue of the lungs affected by metastases of the experimental rat's ovarian tumor at different stages of its development.

Actuality. Transplanted organotropic strain of the tumor of rat's ovary 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 tissue of the lungs affected by metastases of the experimental rat's ovarian tumor at different stages of its development.

Methods. For our investigation we used three-month-old males of laboratory rats that made up three groups (each group consisted of five animals). The group number one included intact animals. Animals of the groups number two and number three were subjected to intravenous transplantation of ten thousand tumor cells. Concentration of theintroduced tumor cells was determined with the help of Gorjaev's count chamber.

Rats of the groups number one and number two were killed on the twentieth day of the experiment. Rats of the group number three were kept till the time of the natural death of the developed tumor (after the twenty-fifth day of the experiment). After the dissection of the thoracic cavity the caudal parts of the lungs were extracted and fixed in solution of formalin. Paraffin sections were stained with haematoxylin-eosin. Histologic specimens were observed under light microscope.

Discussion. On the outside the lungs of the control rats (rats of the group number one) are covered by serous tunic that consists of flattened mesothelium (its thickness is 4,13±0,19 micrometers, its cells contains hyperchromatic elongated nuclei) and subepithelial connective tissue layer which is penetrated by numerous capillaries. The connective tissue layer consists of a large number of cells having oval densely stained nuclei, and of fibres directed along the surface of the organ. Thickness of the serous tunic is 19,2±1,1 micrometers.

The bulk of the pulmonary parenchyma is made up of alveoles, between which the bronchi of different size are located. The alveoles are lined by flattened epithelial cells containing elongated nuclei. There isn't any prominent difference between the diameter of alveoles situated within the peripheral parts of the lungs (21,1±1,6 micrometers) and the diameter of alveoles situates within the internal parts of the organ (23,63±1,26 micrometers). Besides, there isn't any prominent difference between the density of arrangement of alveoles situated within the peripheral parts of the lungs and of alveoles situated within the internal parts of the organ. Within the peripheral parts of the lungs the number of alveoles in one visual field of microscope (ocular 15, objective 40) is 6,73±0,26, and within the internal parts of the organ the number of alveoles in one visual field of microscope is 7,66±0,33.

Alveoles are separated from one another by thin interalveolar septa penetrated by capillaries. The interalveolar septa consist of densely arranged cells (that contain rounded and oval nuclei having well visible nucleoli and masses of chromatin) and thin connective tissue fibres. Within the peripheral parts of the lungs the thickness of the interalveolar septa is 9,75±0,49 micrometers,

 

and within the internal parts of the organ the thickness of the interalveolar septa is 8,73±0,43 micrometers.

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

Wall of those bronchi, the lumen of which is eigh hundred to one thousand micrometers in diameter, contain plates of cartilage 54,05±3,06 micrometers in thickness. The cartilaginous plates contain oval and irregular-shaped cells that are densely arranged. Those cells have prominent boundaries, diameter of the cells is 15,44±0,8 micrometers. Rounded and oval nuclei of the cells (5,38±0,21 micrometers in diameter) contain well visible nucleoli and masses of chromatin.

Mucous tunic of bronchi of any size forms folds that are made up of epithelium and lamina propria. In the bronchi that are eight hundred to one thousand micrometers in diameter, the height of the folds is 62,01±3,01 micrometers. In the bronchi, that are six hundred and fifty to seven hundred and fifty micrometers in diameter, height of the folds is 103,89±5,09 micrometers. In the bronchi, that are three hundred to four hundred micrometers in diameter, the height of the folds is 60,38±3,01 micrometers. In the bronchi, that are two hundred to two hundred and fifty micrometers in diameter, the height of the folds is 64,35±3,3 micrometers. In the bronchi, that are eighty to one hundred micrometers in diameter, the height of folds is 39,25±1,9 micrometers.

Inner surfaces of the bronchi are lined by pseudostratified epithelium the cells of which contain hyperchromic nuclei that are located within middle and basal parts of the cells. Boundaries between the epithelial cells and the basal membrain are not prominent. In the bronchi, that are eight hundred to one thousand micrometers in diameter, the height of the epithelium is 27,69±1,26 micrometers. In the bronchi, that are six hundred and fifty to seven hundred and fifty micrometers in diameter, the height of the epithelium is 20,36±0,86 micrometers. In the bronchi, that are three hundred and fifty to four hundred and fifty micrometers in diameter, the height of the epithelium is 15,56±0,53 micrometers. In the bronchi, that are two hundred to two hundred and fifty micrometers in diameter, the height of the epithelium is 13,33±0,64 micrometers. In the bronchi, eighty to one hundred micrometers in diameter, the height of the epithelium is 10,8±0,5 micrometers.

Lamina propria of the bronchial mucous tunic consists of numerous cells that contain densely stained nuclei of different size, and of thin connective tissue fibres.

Smooth muscle in the bronchial wall represents bundles of densely arranged smooth muscle cells. The bundles are separated by connective tissue layers. The smooth muscle cells contain poorly stained nuclei that are elongated in shape. The specific gravity of the muscle in the bronchial wall increases as the bronchi become smaller but the thickness of the smooth muscle decreases. In the bronchi, that are eight hundred to one thousand micrometers in diameter, the thickness of the smooth muscle is 73,0±3,6 micrometers. In the bronchi, that are six hundred and fifty to seven hundred and fifty micrometers in diameter, the thickness of the smooth muscle is 41,65±2,0 micrometers. In the bronchi, that are three hundred and fifty to four hundred and fifty micrometers in diameter, the thickness of the smooth muscle is 21,72,±1,08 micrometers. In the bronchi, that are two hundred to two hundred and fifty micrometers in diameter, the thickness of the smooth muscle is 17,94±0,8 micrometers. In the bronchi, that are eighty to one hundred micrometers in diameter, the thickness of the smooth muscle is 7,89±0,3 micrometers.

Bronchial adventitia cosists of numerous cells containing rounded and oval nuclei that are densely stained, and of thin fibres. Connective tissue of the bronchial adventitia is gradually continuous with the adjacent interalveolar septa, and with adventitia of the adjacent vessels, that's why boundaries of the bronchial adventitia are not prominent. The walls of the bronchi contain lymphatic nodules occupying all the thickness of the wall and even reach the subepithelial layer.

Lungs of the rats of groups number two and number three contain numerous tumor nodes that are grey in colour. Some of these nodes are situated within the organs, and some of them project out on the surfaces of the lungs. Those nodes are evenly distributed throughout the organ.

In the rats of groups number two the tumor nodes are made up of clusters of densely packed cells. These clusters consist of groups of cells separated by thin layers of homogeneous substance. Within each group, the cells are structurally similar. Some of the cells possess conspicuous boundaries, and their nuclei contain lagre masses of chromatin, other cells show figures of mitosis. Hence we can suppose that the groups of the tumor cells represent isogenous groups, each of which is derived from one maternal cell. The tumor cells are 8,19±0,36 micrometers in diameter, and diameter of their nuclei is 5,14±0,2 micrometers.

The tumor nodes are penetrated by blood vessels. The walls of the blood vessels are gradually destroyed by surrounding tumor cells. Total destruction of the vascular wall causes bleeding into the tumor tissue. Those zones of the tumor tissue, that are adjacent to the zone of the bleeding, are necrotic.

The tumor nodes are surrounded by connective tissue infiltrated by the tumor cells. Those zones of the lungs which are situated between the tumor nodes are destroyed.

In the rats of the group number three the peripheral zones of the intrapulmonary tumor nodes consist of densely packed tumor cells boundaries of which are not conspicuous. Central zones of the tumor nodes are necrotic. The cells of the peripheral zones of the tumor are arranged in groups separated by the layers of homogeneous substance many of which are very wide.

Nuclei of the tumor cells differ from each other by density of the stain and distinctness of the karyolemma and chromatin masses. Average diameter of the nuclei is 7,37±0,24 micrometers. Each tumor node may contain cells having both small-sized densely stained nuclei and large poorly stained nuclei.

Between the groups of the tumor cells there are thin-walled dilated vessels filled by formed elements of blood.

Among the tumor cells there are those which are devoid of nuclei or contain vacuolated cytoplasm. There are also small cavities that remain in places of the entirely destroyed tumor cells.

Conclusions. Intrapulmonary solid form of the ovarian tumor undergoes structural changes in the process of its development. Those changes are followed by destructive and necrotic processes in the tumour tissue. Metastases are characterized by bleeding from the blood vessels the walls of which are destroyed by malignant cells.

 

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Year: 2016
City: Almaty
Category: Medicine
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