[Age-related peculiarities of the hypothalamo-hypophyseo-adrenal system in chronic heterotypic stress].

Age-related peculiarities of the adaptation of the hypothalamo-hypophyseo-adrenal system (HHAS) to the effect of heterotypic stress was studied experimentally in the context of stress-associated behavioral reactions. Young (3 month old), mature (6 month old) and aging (12 month old) Sprague Dawley rats (total number of animals equal to 36) were exposed to chronic heterotypic stressors for 7 days with the subsequent testing of their behavioral responses. Histological changes were studied in the hypothalamus, pituitary and adrenal glands as compared to age-matched control; immunohistochemical reactions were performed to demonstrate CRF, ACTH, ED1, PCNA and caspase-3 with subsequent image analysis. In the aging organism, as compared to young and mature animals, the degree of HHAS activation indicated the dissociation in its central part and adaptive desensitization prevention, typical to young and mature animals. Specifically, in the aging animals exposed to stress, high hypothalamic CRF expression was noted in association with relatively low hypophyseal ACTH expression and high level of adrenal activity. Reduced HHAS plasticity in the aging animals as compared to that in the other age groups, corresponded to their behavioral changes, demonstrating the reduced capacity of the aging organism to adapt to the exposure of unpredictably changing stressors.

Morphological and phenotypical characteristics of human osteoblasts after short-term space mission.

Morphological and phenotypical signs of cultured readaptation osteoblasts were studied after a short-term space mission. The ultrastructure and phenotype of human osteoblasts after Soyuz TMA-11 space flight (2007) were evaluated by scanning electron microscopy, laser confocal microscopy, and ELISA. The morphofunctional changes in cell cultures persisted after 12 passages. Osteoblasts retained the drastic changes in their shape and size, contour deformation, disorganization of the microtubular network, redistribution of organelles and specialized structures of the plasmalemma in comparison with the ground control cells. On the other hand, the expression of osteoprotegerin and osteocalcin (bone metabolism markers) increased; the expression of bone resorption markers ICAM-1 and IL-6 also increased, while the expression of VCAM-1 decreased. Hence, space flight led to the development of persistent shifts in cultured osteoblasts indicating injuries to the cytoskeleton and the phenotype changes, indicating modulation of bone metabolism biomarkers.

Effects of space mission factors on the morphology and function of endothelial cells.

The structure and functions of endothelial cells after space mission were studied by electron and laser confocal microscopy, image analysis, and MTT test. The endothelial cells changed significantly (proliferative activity, size, contours, shape, distribution of mitochondria and microtubules) in comparison with controls on the Earth. These changes indicated injuries in the cytoskeleton and impairment of the barrier function of the cells, which presumably contributed to the development of endothelial dysfunction.

Immunohistochemical characteristics of the hypophysis in normal conditions and chronic stress.

Quantitative immunohistochemical methods were used to assess activation of the hypothalamo-hypophyseal-adrenocortical system at the level of its central component - the adenohypophysis - in the growing body during chronic exposure to psychoemotional stressors of different strengths. Sprague-Dawley rats aged 30 days were subjected to "mild" or "severe" immobilization stress for 5 h per day for seven days. Animals were decapitated at the end of the last stress session and the endocrine glands (hypophysis, adrenals) were harvested, weighed, and embedded in paraffin; sections were stained with hematoxylin and eosin, and also immunohistochemically using monoclonal antibodies to adrenocorticotropic hormone (ACTH) and proliferating cell nuclear antigen (PCNA) following by automated image analysis. These studies showed that stress-associated hyperplasia of corticotropocytes in rats of pubertal age was due more to the differentiation of existing immature precursor cells than to cell proliferation.

Ultrastructural characteristics of synovial effusion cells in some arthropathies.

OBJECTIVE: To evaluate the range of activation changes of polymorphonuclear leukocytes (PMN) and the ratio of apoptosis and necrosis in synovial effusions of patients with various arthropathies, and to reveal possible correlations with clinical variants of joint inflammation. METHODS: Synovial effusions were aspirated from the knee joints of patients with rheumatoid arthritis (RA, 28 cases), and seronegative spondyloarthritides (SSA): Reiter's disease (RD, 9 cases), peripheral form of the ankylosing spondyloarthritis (6 cases) and psoriatic arthritis (6 cases); and primary osteoarthritis (OA, 9 cases). Cytospin preparations were processed for transmission electron microscopy and assessed for the incidence of apoptosis, necrosis, and cytophagocytic cells (CPC) in the synovial fluid (SF). The range of activation changes of the neutrophil granulocytes, the dominating cell population in the arthritic SF, was evaluated. RESULTS: In all arthropathies under investigation most of the synovial effusion cells had intact ultrastructure with a certain amount of apoptotic cells dominating over the cells with signs of necrosis, and a few CPC. The highest rate of apoptosis was discovered in the synovial effusions of patients with RA, the lowest in those with OA, while the rate of CPC among the inflammatory joint diseases was the lowest in RA. In RA the current disease activity correlated with the incidence of apoptotic cells and CPC, while the clinical stage was related only to the CPC rate. These data suggest that in RA, despite exposure to the anti-apoptotic signals, apoptosis of the synovial effusion PMN is maintained at a significantly higher level than in non-rheumatoid arthropathies, both inflammatory (SSA) and degenerative (OA), providing elimination of the neutrophils accumulating in the joint cavity and thus stimulating resolution of the joint inflammation.

Ultrastructural changes of the articular cartilage in some arthropathies with special reference to chondrocyte cell death.

OBJECTIVE: To determine in situ using TEM the balance of apoptosis and necrosis in the articular cartilage of patients with inflammatory (rheumatoid arthritis and seronegative spondyloarthritis) and degenerative (osteoarthritis) joint diseases and to establish possible correlation between the cell death rate and the matrix vesicles formation. METHODS: Cartilage samples of the knee joint were obtained from patients with rheumatoid arthritis (RA, 18 cases), osteoarthritis (OA, 22 cases), Reiter's disease (RD, 9 cases), peripheral form of the ankylosing spondyloarthritis (AS, 6 cases) and psoriatic arthritis (PA, 6 cases) during arthroscopy or knee surgery. Normal samples taken from autopsy cases without a history of joint diseases were used as control. Samples were processed for TEM with subsequent semi-quantitative estimation of the cell death rate in the superficial, middle and deep zone of non-calcified articular cartilage, and computer-aided ultramorphometric evaluation of the matrix vesicles of different types. RESULTS: Both apoptotic and necrotic cell death could be identified in the cartilage of patients with inflammatory joint diseases, including seronegative spondyloarthritides and degenerative arthropathies. Apoptosis dominated over necrosis in all examined arthritides, including RA patients in which necrosis of the chondrocyte was the most frequent among arthropathies, while the highest apoptotic cell death rate was discovered in OA in which it correlated with the volume and numeric density of the matrix vesicles. These data provide evidence that apoptosis may contribute to the cartilage breakdown not only in RA and OA but also in the seronegative spondyloarthritides, which had a significantly higher apoptotic rate than the normal cartilage.