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 in case of different doses of transplanted tumor strain.
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 in case of different doses of transplanted tumor strain.
Methods. For our investigation we used three-month-old males of laboratory rats that made up four groups (each group consisted of five animals). The group number one included intact animals. The groups number two, number three and number four included rats that were subjected to intravenous transplantation of tumor cells. Rats of the group number two were injected with one thousand tumor cells, rats of the group number three were injected with ten thousand tumor cells, and rats of the group number four were injected with fifty thousand tumor cells. Concentration of the introduced tumor cells was determined with the help of Gorjaev's count chamber.
Rats of the group number one were killed on the twentieth day of the experiment. Rats of the groups number two, number three, and number four were kept till the time of the natural death ofthe 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 were evenly distributed throughout the organ.
In the rats of the group number two there was single large intrapulmonary metastasis about one centimeter in diameter. Central part of the metastasis was necrotic. As a result of microscopic investigation it is established that the secondary neoplasm is surrounded by connective tissue capsule penetrated by blood vessels. Trabeculae arising from the capsule extend into the tumor. The capsule has loosen structure caused by tumor cell infiltration. The tumor cells situated within the capsula are rounded, oval, or polyhedral in shape, their boundaries are distinct, their granular cytoplasm is well stain with eosin. Average diameter of the tumor cells is 12,28±0,46 micrometers. Their centrally situated and eccentric nuclei are rounded, oval, or irregular in shape. Diameter of the nuclei is 6,08±0,3 micrometers. Some of the nuclei are densely stained, other nuclei have distinct karyoplasms and masses of chromatin.
Within the capsule one can find polynuclear tumor cells that may contain more than ten nuclei. Such cells are rounded, polyhedral, and irregular in shape, their boundaries are distinct. Rounded and oval nuclei of the tumor cells have well visible karyolemma and masses of chromatin.
Subcapsular zones of the tumor are penetrated by small vessels containing formed elements of blood. Those zones mainly consist of cells the boundaries of which are indistinct. Their rounded and oval nuclei have well visible karyolemma and masses of chromatin. Diameter of the nuclei is 8,11±0,35 micrometers.
Among the tumor cells of the subcapsular zone there are large polynuclear ones. Such cells have distinct boundaries, and their cytoplasm is well stain with eosin. Their nuclei are characterized by distinguishable karyolemma and nucleoli.
Some of the tumor cells have signs of destruction (absence of nuclei, vacuolated cytoplasm). There are also small cavities that remain in places of entirely destroyed tumor cells.
Towards the centre of the tumor tissue the number of the cells containing pyknotic nuclei and vacuolated cytoplasm increases. Within the deeply situated tumor zones there are many cavitied that remain in places of entirely destroyed cells.
Central part of the tumor is necrotic. It represents homogeneous substance the peripheral zones of which contain pyknotic nuclei of destroyed tumor cells. Its central zones contain cavities filled with formed elements of blood.
In the rats of the groups number three and number four the lungs 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 the group number three the tumor nodes are one to two millimetres in diameter. Each of those nodes is surrounded by connective tissue capsule the structural elements of which are arranged rather densely. Within the capsule there are not numerous tumor cells some of which are present in groups.
Central parts of tumor nodes may be necrotic. In the tumor nodes of the smallest size the necrotic centres frequently are absent. As the size of the nodes increases the specific gravity of the necrotic centres becomes greater.
The smallest tumor nodes are made up of densely arranged cells the boundaries of which are indistinct. Rounded and oval nuclei of the cells are characterized by well visible karyolemma and masses of chromatin. The nuclei are 6,47±0,17 micrometers in diameter. The tumor cells are present in groups separated by thin layers of homogeneous substance.
Next to the necrotic centres almost all the tumor cells have signs if destruction. Necrotic tissue is unstructured and contains fragments of nuclei.
In the tumor nodes of the greatest size the necrotic tissue occupies the most part of the metastasis. Besides, within the peripheral parts of the nodes there are also some small necrotic zones. Intact tumor tissue consists of densely arranged cells the boundaries of which are indistinct. Rounded and oval nuclei of the cells have well visible karyolemma and masses of chromatin. Diameter of the nuclei is 6,2±0,22 micrometers. Tumor cells are arranged in groups separated by wide layers of homogeneous substance.
Among the tumor cells there are those having signs of destruction. The bulk of the destroyed tumor cells are situated next to the necrotic centres.
In the rats of the group number four the lungs contain numerous tumor nodes that are four hundred to two thousand micrometers in diameter. Many of them contain necrotic centres within which there may be cavities filled with formend elements of blood. Presence and absence of the necrotic tissue did not depend on the size of the nodes. Big nodes may be devoid of necrotic centres, while small metastases may contain necrotic centres of considerable size. Some big nodes contain both necrotic centres and peripheral necrotic zones.
Intact tumor tissue mainly consists of densely arranged cells the boundaries of which are indistinct. Those tumor cells are present in groups separated by layers of homogeneous substance. Nuclei of the cells are characterized by well visible karyolemma and nucleoli. Diameter of the nuclei is 7,76±0,25 micrometers. Between the groups of the tumor cells there are sometimes vessels filled by formed elements of blood.
On the outside the tumor nodes are surrounded by connective tissue capsule that is penetrated by numerous blood vessels. Within the capsule there are some tumor cells that are present singly.
Conclusions. Intrapulmonic form of the experimental rat's ovarian tumor is characterized by structural differences depending on transplanted doses. The number of intrapulmonic metastases is directly proportional to the transplanted dose, the size of tumous nodes is inversely proportional to the dose. The metastases are vascularized and may contain central necrotic zones.
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