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Experiment was evaluated on 40 male Wistar rats. On the experimental model of mandible injury, bone autologous graft from tibia was placed on the surface of mandible (host bone). In the main experimental group, consisting of 20 animals, autologous rat adipose-derived stromal cells (ADSCs) were inoculated in space between autograph and host bones. ADSCs were not inoculated in the group of comparison. In experimental group with inoculated cells, the formation of a new fibroreticular bone structures in space between autograph and host bone was observed. These structures further underwent secondary reorganization and differentiation during the process of remodeling. As a result of the conducted study it was shown that in the experimental group by the day 180, statistically significant reduction of the area occupied by an immature fibroreticular bone took place. The reported phenomenon could be explained as a result of decline of the number of active cells in the population of inoculated ADSC, which is in consent with theory of limited cell division number due to telomeres shortening, described by Hayflick L. and Moorhead P.S. (1961).

In experiments on 48 rats of line Wistar, divided at 2 groups (first--basic group and 2-d group--group of comparison) through the use of morphological method was researched influence of mesenchymal stem cells (MSC) inoculated in the area of autogenic bone graft from tibia fixed at the surface of the jaw. The animals of group of comparison didn't get MSC. Time frames of watching: 21, 60, 120 and 180 days, 6 rats on the point of experiment in either of the two of the group. Data of this research had shown the intensification of bone formation process in the basic group of experiment under the action of the inoculation of autogenic MSC from adipose tissue, and as consequence of it, in eventual, merge of bone formations in a single entity.

In experiments on rats CD comparative studies have been carried out which is the effect of osteoplastic material NORIAN CRS, the rate of bone regeneration after mandibular dental implants (titanium screw) and the combined effect of these processes NORIAN CRS protein and protein (Emdogein). Functionality and maturity of the newly formed bone tissue was evaluated by histological and biochemical methods. The results suggest that the use of osteoplastic material NORIAN CRS is the 120 days leading to almost complete regeneration of bone tissue. It was also found that the combined use of NORIAN CRS and protein Emdogein impractical because adding Emdogein not accelerate bone regenerative process, but in the early postoperative period may cause an inflammatory reaction.

We studied the fate in vitro cultured human stem/progenitor cells after transplantation into rat brain. The cells from human fetuses at 8-12 weeks' gestation were cultured in vitro for 14 days and transplanted into the brain of 10-day-old and adult rats. Microscopic examination showed that human stem/progenitor cells migrated into various regions of rat brain. Immunohistochemical assay demonstrated that some cells differentiated into astrocytes and neurons, while others retained the embryonic phenotype.

It has been shown autoradiographically using 3H-lysine-3H-glycin mixture that acute hypoxic hypoxia leading to mass diffuse dystrophy of brain cortex neurons in rats causes a statistically significant decrease in the level of protein synthesis in cortical neurons. The biochemical study of the same material using 3H-leucine has demonstrated that the overall level of protein synthesis in the total cortical tissue (in nerve and non-nerve cells) is not reduced after hypoxia probably due to a high resistance of glial and other non-nerve cells to oxygen deficiency. Transplantation of embryonic nervous tissue into the brain of rats exposed to hypoxia results not only in normalization of the structure of a part of dystrophic neurons but also in a statistically significant increase in the level of protein synthesis which is retained up to the end of the experiment (i. e. for 120 days following the operation) in the total cortical tissue and reaches the normal value in neurons as established autoradiographically.

The aim of this work was to study the effect of hypoxia on blood-brain barrier (BBB) permeability to blood globulins in adult Wistar rats; the influence of hypoxia combined with embryonic nervous tissue (ENT) transplantation; as well as that of hypoxia and brain injury without transplantation. Impairments in BBB were detected by a change in the brain vessels permeability to blood globulins on the basis of Coons's reaction. BBB permeability was checked at different time intervals: from one to thirty five days after the hypoxia seance, hypoxia and brain injury, and hypoxia with ENT transplantation. BBB permeability to blood globulins was found to be significantly increased after the exposure to hypoxia, reaching its maximum by the 7th day and returning to normal only by the 30th day after the hypoxia seance. Similar results were obtained in the case of brain injury following an exposure to hypoxia. Although there was an insignificant decrease in BBB permeability seen one day after the rats were subjected to brain injury, the duration of BBB restoration was the same as in hypoxia-exposed rats (30 days). In the case of ENT transplantation into the brain of adult hypoxia-exposed rats the restoration of the damaged BBB proceeded considerably faster than in hypoxia-exposed rats with brain injury. By the end of the first week after the transplantation the functions of BBB were completely normalized and in some cases the barrier was already restored.

Our early studies (Polezhaev and Alexandrova, 1986) have shown that acute hypoxic hypoxia in rats causes mass (up to 36%) diffuse dystrophy of brain cortex neurons and that after transplantation of embryonic nervous tissue (ENT) into the brain of hypoxia-exposed rats the dystrophy and death of cortical neurons are reduced to 25% due to normalization of a part of dystrophic neurons. In the present work we studied changes in the RNA synthesis in neurons and in the total brain cortex of rats after hypoxia and subsequent transplantation of ENT into their brain by the autoradiographic and biochemical methods using 14C-adenine. It has been shown that under the action of hypoxia the RNA synthesis in neurons and in the total brain cortex of rats is reduced and after transplantation of ENT into the brain of these rats the RNA synthesis is stimulated and normalized both in neurons and in the total brain cortex.

We studied the behavior and differentiation of human and rat neural stem cells after transplantation in the adult rat brain without immunosuppression. The rat stem cells were isolated from the presumptive neocortex of 15-day-old embryos. The human cells were isolated from the ventricular brain zone of 9-week-old embryos and cultivated for two weeks before transplantation. The results of histomorphological studies suggest that the microenvironment factors did not suppress the growth or development of transplanted stem cells. Both rat and human embryonic multipotent neural cells showed similar behavior and differentiation into neurons and glial cells. After transplantation, they continued to mitotically divide and migrated from the graft area to the surrounding tissue of a recipient brain. The presumptive glial cells migrated preferentially along the capillaries and fibrous structures of the recipient brain. Similar behavior of the rat and human neural stem cells in the microenvironment of the recipient adult rat brain and the absence of immune reaction suggest that the transplantation into the rat brain may serve as a model for studying the developmental biology of the human stem cells.