[State of the rabbit aorta after orthostatic tests].
Morphometric examinations of endothelium film preparations and histological investigations of aortic sections were performed 1 to 50 days after exposure of rabbits to orthostatic tests. Immediately and 1.5 months after exposure the intima showed a significant increase of endotheliocytes, vacuolization of the cytoplasm and nuclei, development of karyopyknosis and karyolysis as well as increase of monocytes and lymphocytes. Beginning with day 4 the inner surface of the intima displayed microthrombi and beginning with day 7 the media showed necrotic changes, which may cause wall deformation due to the destruction of the collagen and elastic layers. At the same time the endothelium exhibited adaptive-compensatory processes, which included increased mitotic activity of endotheliocytes and their intracellular regeneration. The identification of the coefficient of variation of centered ordinates helped to distinguish an early phase of orthostatic responses (days 1-2), phase of adaptive and compensatory changes (3-15), and phase of remote effects and stabilization of the aortic endothelium. These observations should be taken into consideration when determining optimal time periods of recovery after lesions caused by acute fluid shifts.
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D000818:Animals; D001013:Aorta, Thoracic / Q000473:pathology* / Q000648:ultrastructure; D004730:Endothelium, Vascular / Q000473:pathology* / Q000648:ultrastructure; D006965:Hyperplasia / Q000209:etiology; D007103:Immobilization / Q000009:adverse effects*; D008955:Models, Cardiovascular; D009336:Necrosis; D011187:Posture; D011817:Rabbits; D013194:Staining and Labeling; D013997:Time Factors
Sostoianie aorty krolikov posle ortostaticheskogo vozdeĭstviia.