Vol 147, No 1 (2015)

The aim of this study was to determine the distribution of GABAergic neurons in pneumotaxic center structures (parabrachial complex medial subnucleus and Kölliker-Fuse nucleus) in norm and in deficiency of serotoninergic system during the prenatal period of development in Wistar rats. Reduction of endogenous serotonin levels in fetal rats was achieved by tryptophan hydroxylase inhibition with para - chlorophenylalanine (PCPA), which was administered to female rats on Day 16 of gestation. Material was obtained from the area of the pons from experimental and control (intact) rat pups at early postnatal (Days 5, 10 and 12) and juvenile (Day 20) periods. At each time point, 5-6 animals were studied from both experimental and control groups. To demonstrate GABAergic neurons, antibodies against glutamate decarboxylase (GAD-67), the enzyme involved in its synthesis, were used. The results have shown that Kölliker-Fuse nucleus contained a population of GABAergic neurons at early postnatal period, the size of which was preserved until juvenile age. In parabrachial complex medial subnucleus during the early postnatal period, a small number of GABAergic neurons was detected, which was somewhat increased by juvenile age. Serotonin deficiency in pneumotaxic center structures lead to a reduction of the numbers of GABAergic neurons, GABAergic synapses and their clusters. A reduction of serotonin levels during the prenatal period may cause the disturbances in the inhibitory afferent signaling of the pneumotaxic center nuclei and lead to the changes of local inhibitory GABAergic networks in its nuclei, resulting in the disturbances of the inhibitory processes in the center structures.

The peculiarities of the structure, skeletotopy, and syntopy of the lumbar lymphatic collector were studied on 20 5-8 week-old embryos and on 80 9-36 week-old fetuses using a complex macro-microscopic method. It is found that the lumbar lymphatic collector in fetuses at 9-10 weeks was represented by retroperi toneal and retroaortic lymphatic sacs that had a fusion mode of formation and were interconnected. Retroperitoneal sac was located in the projection of L I-L IV and was in contact with the anterior surface of the abdominal aorta and inferior vena cava, aortic lumbar paraganglia, abdominal aortic plexus and ganglia of sympathetic trunk. Retroaortic sack at L I-L II was adjacent to posterior surface of the aorta, the lumbar vertebrae and the medial crus of the diaphragm. These topical relations were preserved throughout the whole fetal period. However, in fetuses of 11-13 weeks lymphatic sacs formed the lymphatic plexuses, while in fetuses of 14-36 weeks they formed lumbar lymph nodes and their interconnecting vessels.

Methods of light microscopy were used to study the morphological changes of the oral cavity mucosa in rats (n=48) in chronic renal failure (CRF) of various degrees. It was found that after 6 months of modeling of mild and moderate CRF, lamina propria of the oral cavity mucous membranes was diffusely infiltrated with leukocytes. At the same time, relative density of the distribution of the components of blood and lymphatic vascular bed was increased. In severe CRF, the atrophy and hyperkeratosis of the epithelium of the oral cavity mucous membrane developed, while the lamina propria demonstrated sclerosis and significant increase of leukocyte (primarily neutrophil and monocyte) and macrophage numerical density with the formation of small leukocyte infiltrates. In addition, in moderate and severe CRF, the number of eosinophils and plasma cells was increased in the lamina propria which indicates the possible presence of allergic component in the initiation and maintenance of its inflammation.

The study aims to clarify the influence of experimental cholestasis mother on the structure of the liver of young rats in early postnatal development (Day 2) and to explore the possibility of the correction of these disturbances with Ursofalk drug. Material was obtained from 30 outbred albino rat pups and studied using histological, histochemical, morphometric and electron microscopic methods. It was found that under the influence of maternal cholestasis, the liver of the offspring demonstrated the dilation of sinusoidal capillaries, the decreased activity of succinate dehydrogenase and increased activity of NADH dehydrogenase in hepatocyte cytoplasm, the development of significant ultrastructural abnormalities (disappearance of lipid droplets, accentuated heterogeneity of mitochondrial size and shape, increased number of lysosomes). The application of Ursofalk partially restored hepatocyte structure and metabolism.

The dynamics of biodegradation of «CollapAn» osteoplastic material was studied after its implantation into the defect of the femoral diaphysis in 30 rats. Computed tomographic analysis of the healing of bone defects was conducted with the determination of the optical density of bone tissue in Hounsfield units. Since Day 30 of the experiment, the appearance and further progress of the radiographic signs of bone tissue neoformation and maturation were noted exactly along the contours of osteoplastic material, together with the gradual disappearance of the defect from the side of bone cortical layer and simultaneous increase of the optical density of the intermediary and endosteal part of the regenerate. At Day 120, regenerate optical density exceeded the absolute optical density of the parent bone; simultaneously, during this period no full recovery of the original shape of the bone took place, while parent bone rarefication was identified during all the periods of observation.

The peculiarities of regeneration of knee articular cartilage were studied experimentally in adult Wistar rats (n=25) using the methods of optical and electron microscopy, histochemistry and x-ray electron probe microanalysis after modeling marginal perforated defect and implantation of granulated mineralized bone matrix (MBM) into the damaged zone. This biomaterial was demonstrated to have marked chondroinductive properties, to provide prolonged activation of reparative process, accelerated organotypical remodeling and restoration of the damaged articular cartilage. The data obtained indicate the possibility of MBM application in clinical practice for the treatment of injuries and diseases of the articular cartilage.

The review summarizes the current data on synaptophysin (SYP), its functional role in the cell and the use of SYP immunocytochemistry for labeling the synaptic contacts. SYP is a transmembrane glycoprotein found in small presynaptic vesicles of the nerve cells and in microvesicles of the neuroendocrine cells. Literature data and the authors’ own experience suggest that currently SYP is an important synaptic marker, which allows, with the use of light and confocal laser microscopy, to obtain the reliable data on the morphological organization of the synaptic structures in the central nervous system. It is also indispensable in the study of the efferent innervation of the internal organs. Applicatioin of the quantitative analysis of SYP-immunopositive structures using light and confocal laser microscopy allows to solve some problems that previously could be solved only by using electron microscopy.