Vol 130, No 6 (2006)

Ultrastructural characteristics of neuroendocrine neurons were studied in amygdala dorsomedial nucleus (DMN), which is one of main zones of sexual dimorphism, in 12 Wistar rats with the body mass of 250-300 g, 3 males and 9 females at different stages of the estrous cycle. In each animal, an average of 50 DMN neurons were examined and their functional state was analyzed on the basis of their ultrastructural characteristics. Morpho-functional classification is proposed, that reflects hormone-dependent variations in neuronal activity. It was established that DMN neurons could be found in different structural and functional states, that may be classified as the state of rest, moderate activity, increased activity, stress (peak activity), decrease in activity (two types), return to an initial state and apoptosis. At the stage of estrus, the neurons in the state of increased activity (40% of the total population) and peak activity (26%) were found to prevail. In metestrus, most of the neurons were in the state of type I decrease in activity (with an increase in nuclear heterochromatin content - 30% of the cells); peak activity and increased activity were found in 25% and 20% of neurons, respectively. In diestrus, the neurons in the state of rest, moderate and increased activity, peak activity and type I decrease in activity were represented in approximately equal proportions (18%, 21%, 18%, 20% and 16%, respectively). In males, 35% and 22% of neurons, respectively, were found in the state of increased activity and peak activity. Neuronal death was detected only in males.

Цель работы - выявить особенности регуляции апоптоза в нейросекреторных центрах старых (в возрасте 18 мес) мышей при воздействии иммуномодулятора интерферона-альфа (ИА) в сравнении с таковой у молодых (2-месячных) мышей. Показано, что возрастная активация апоптоза в супраоптическом (СОЯ) и паравентрикулярном (ПВЯ) ядрах опосредуется различными путями и может быть результатом изменений в соотношении синтеза про- (Bax) и антиапоптотических (Mcl-1, Вс1-2) молекул. Кроме того, сигнальный каскад апоптоза у молодых мышей при действии ИА идентичен в обоих ядрах, тогда как у старых мышей есть различия между СОЯ и ПВЯ.

The localization and morphological features of viscerosensory neurons of sacral spinal ganglia (SSG), innervating the colon, were investigated. In urethane anaesthetized cats, the solution of horseradish peroxidase was injected under the serosa of ascending and descending parts of the colon as well as of the rectum. After 48 hours animals were repeatedly anesthetized and trans-cardially perfused. Sections of SSG were stained according to Mezulam protocol (1978). All the regions of the colon studied were shown to receive afferent innervation from neurons of SSG SI, SII and SIII. Maximum number of the labeled cells was detected in SSG SII. The intensity of afferent innervation of the colon by the neurons of SSG was found to increase along its length in cranio-caudal direction.

Using the quantitative immunohistochemistry, the immunomodulatory effect of different types of stressors (physical and psychoemotional) on the thymus of growing experimental animals was assessed. Sprague-Dawley rats aged 21 day were exposed either to physical (water immersion) or emotional «expectation» stress for 5 hours daily during 7 consecutive days. After the final exposure to stress, animals were sacrificed, thymus was obtained for weighting and was processed for routine histology and immunohistochemistry (CD3, CD8, ED1, PCNA) with subsequent automatic image analysis. The finding obtained have demonstrated severe accidental thymic involution in both groups of experimental animals, which was more prominent under the effect of the physical stressor as compared to «purely» psychoemotional stressor. The major factors of poststress thymic hypoplasia were the increased apoptosis of the cortical thymocytes and inhibition of their proliferation, but not their increased transport to peripheral immune organs.

Electron microscopy was used to study the cellular composition of dog pancreatic islets. Four types of endocrine cells were detected: A, B, D and PP. Б cells were the predominant population within the islets. Differences in cellular organization of A and B cells were shown to be caused by the phases of the process of hormone synthesis. Insulin-containing secretory granules in B cells had a crystalloid structure, similar to that in B granules of insulin-containing cells in human pancreatic islets. In the exocrine portion of the pancreas, acino-insular cells were detected that simultaneously contained B granules and zymogen granules in their cytoplasm. It is suggested, that their presence is indicative of one of possible directions of pancreatic islet regeneration.

The aim of this study was to develop an optimal and easy protocol for immunocytochemical demonstration of nestin (an intermediate filament protein which is believed to be a neuronal stem cell marker) in paraffin sections of rat brain with target retrieval procedure being omitted for better preservation of the neural tissue structure. The influence of fixation, character of blocking of nonspecific antibody binding, temperature and time of incubation on the results of immunocytochemical reaction was studied. On the basis of the results obtained, we propose a processing protocol allowing distinct demonstration of nestin in rat brain cells together with the optimal preservation of the nervous tissue structure.

This paper presents the critical analysis of the data published in recent literature, which concern the role and significance of stem cells (embryonic stem cells and progenitor cells) in the processes of reparative morpho- and histogenesis in the different animal and human organs. Possible negative effects of the application of stem cells for the stimulation of reparative histo-and organogenesis are discussed. Special attention is drawn to the necessity of more cautious and balanced approach to the use of stem cells for stimulation of repair processes in the organism.