Cell and Tissue Biology

The aim of the study is to elucidate the participation and functional role of the preoptic-hypophysical neurosecretory system (PHNS) in the process of reproduction of valuable commercial fish species with various biological features of spawning. The participation of the PHNS in fish breeding implementation was shown by histomorphological, immunohistochemical and electronic-microscopical researches with the use of quantitative morphometry. The activation of nonapeptide neurohormones discharge into blood circulation from posterior neurohypophysis at the beginning of spawning and the following decrease of functional activity of system after it are revealed in every one-time spawning fish species independently on its season (spring-, autumn- and winter-spawning genera: Acipenser, Oncorhynchus, Lota). The similar reaction of neurosecretory system is observed morphologically under the experimental stress - impacts of hypertonic medium on adult acipenseridae fish. The diphasic reaction of neurosecretory system conforming to stages of an alarm and a resistance of stress, is considered to be the reflection of its participation in protective-adaptive reactions of an organism to a physiological stress arising at breeding period of one-time spawning polycyclic fishes. At monocyclic species at once after spawning there becomes the blockage of function of releasing of neurohormones from posterior neurohypophysis corresponding to supernatural inhibition of system at distress. Discussion of the functional role of nonapeptide neurohormones in implementation of reproduction is based on the analysis of morpho-functional mechanisms of neurosecretory system participation in spawning. The constructive schemes of neurosecretory system participation at all phases of spawning are provided.

Hypertension is one of the most common cardiovascular diseases, characterized by a persistent increase in blood pressure. Morphological changes in the heart wall begin to develop in the early stages of the disease, and the immune cells of the heart, macrophages, play a key role in the pathogenesis of this process. The aim of the work is to study morphofunctional features of macrophages in the myocardium of spontaneously hypertensive rats (SHR) using an immunohistochemical reaction to the microglial marker Iba-1. The myocardial samples of Wistar (n = 8) and SHR (n = 7) rats were used for the study. Immunohistochemical study was performed using antibodies to Iba-1 and CD68 proteins. In SHR rats, changes in the structural organization of the myocardium and accumulations of Iba-1+ cells in areas with deteriorating cardiomyocytes were detected. Some of these cell clusters were shown to be associated with collagen fibers, while other similar clusters were not associated with fiber proliferation. Most of the Iba-1+ cells identified were characterized by the presence of the macrophage marker CD68 in the cytoplasm. The obtained data indicate the involvement of myocardial macrophages subpopulations in the development of cardiopathology in arterial hypertension.

Extreme sensitivity of inhibitory neurons of the developing brain to damaging factors in the early postnatal period is of particular interest for studying possible mechanisms of neonatal encephalopathy, cognitive disorders, development of various forms of epilepsy, etc. In this regard, the aim of the work was to study the response of different types of interneurons in the fascia dentata of the hippocampus to hypoxia in the neonatal period. The study was conducted on a model of human premature pregnancy. Hypoxia was introduced on the 2nd day after birth in a special chamber with an oxygen content of 7.8% in the breathing mixture. GABAergic neurons were detected by immunohistochemistry. The fascia dentata was studied on the 5th and 10th postnatal days (P5, P10). At P5, 5 types of GABA-containing neurons were identified in the fascia dentata: MOPP and HIPP cells associated with the perforant path, HICAP cells associated with the commissural-associative path, chandelier cells and basket cells innervating granule neurons of the fascia dentata. A significant increase in the number of interneuron populations, their growth and a significant increase in the GABA content by the end of the neonatal period were, to a greater extent, characteristic of the MOPP, HIPP and HICAP interneurons. Additional evidence was obtained for the early differentiation of HIPP cells associated with the perforant path. The effect of neonatal hypoxia led to a decrease in the number of populations of different types of interneurons, a delay in cell growth and a decrease in the GABA content. These deviations are especially pronounced in the populations of HICAP and HIPP cells associated with afferent fibers and basket cells, which are considered key elements involved in the implementation of hippocampal functions both in norm and pathology. The identified deviations may affect the structural and functional organization of the fascia dentata in the early neonatal period and serve as the basis for the development of neonatal encephalopathy.