MORPHOLOGICAL CHANGES OF RATS’ CEREBRAL CORTEX UNDER CONDITIONS OF DMH-INDUCED EXPERIMENTAL CARCINOGENESIS

Abstract

Abstract. The progression of the endogenous intoxication syndrome accompanies the development of any neoplasm. The infl uence of toxic products leads to signifi cant disruptions in homeostasis, which seriously aff ects the central nervous system, specifi cally the cortex of the large hemispheres. Therefore, the purpose of our study was to establish changes in the morphological reorganization of the cortex of the large hemispheres of rats with DMG-induced adenocarcinoma in situ. The study used 85 mature white male rats. All animals were divided into 2 groups: I – 35 intact animals and II – 50 animals with DMG-induced colon adenocarcinoma.Histological slides of the brain were prepared by the generally accepted methodology. The drugs were studied using a MICROmed SEO SCAN light microscope and photo- documented using a Vision CCD Camera. The histological organization of the cerebral cortex of intact animals had typical histoarchitectonics. In the fi rst three stages of the experiment, moderate changes in the morphological organization of the cortex were detected compared to the control group. The fourth stage of DMG-induced carcinogenesis modeling was characterized by the manifestation of morphological changes, a decrease in the number of normochromic, an increase in hypo- and hyperchromic neurocytes, and the appearance of cell alteration signs. Typical for this period also was the progression of hemodynamic disorders: venous hyperemia, stasis, aggregation of erythrocytes («sludge»), and an increase in perivascular and pericellular edema. At the 5th and 6th stages of the experiment, a violation of the cytoarchitectonics of the cortex was revealed. Destructive changes in neurocytes increased. Betz cells were in a state of tigrolysis, sometimes in total one. A decrease in the Nissl substance in neurons confi rmed their impaired functional capacity. Increased permeability of capillary walls led to severe pericellular edema of neurocytes. Intracellular edema was also detected in most neurocytes. The 7th stage of the induced carcinogenesis was characterized by the presence of severe destructive changes in neurons: an increase in the number of hypo-, hyperchromic, sharply hypo-, and sharply hyperchromic neurocytes, a fragmentation of neurocyte neuroplasm, most of Betz cells in a state of total tigrolysis, a decrease in the content of Nissl substance in them, up to its complete absence. Blood capillaries had a deformed wall and signifi cantly enlarged perivascular spaces. Consequently, the study established the development and dynamics of alterative changes in the neurocytes of the cerebral cortex caused by DMG-induced carcinogenesis. These disorders were characterized by alteration of neurocytes and progressive microcirculation disorders. All identifi ed morphological changes in the brains of aff ected animals prove their dependence on the duration of carcinogen exposure.