Vascularization of the Damaged Nerve under the Effect of Experimental Cell Therapy.

Quantitative analysis of blood vessels in the distal segment of rat sciatic nerve after its ligation for 40 sec and subperineurial administration of mesenchymal stem cells or dissociated cells of rat embryonic spinal cord was carried our by immunohistochemical tracing of von Willebrand factor, a marker of endothelial cells of blood vessels. It was found that the number of blood vessels per unit area of the nerve trunk in 21 days after injury and administration of mesenchymal stem cells increased by more than 1.5 times in comparison with the control (damaged nerve). After administration of dissociated cells of the embryonic spinal cord, this effect was not observed. It is assumed that mesenchymal stem cells stimulate the growth of vessels of the damaged nerve via production of angiogenic factors.

Effect of allotransplants containing dissociated cells of rat embryonic spinal cord on nerve fiber regeneration in a recipient.

Regeneration of nerve fibers in rat sciatic nerve was quantitatively assessed after injury (ligation) and injection of dissociated cells derived from embryonic spinal cord. A suspension of dissociated spinal cord cells from rat embryos was transplanted under the perineurium of a nerve trunk. After transplantation, bromodeoxyuridine-labeled precursor cells survived and retained the label for more than 2 months; some of these cells differentiated into NeuNpositive neurons. Analysis of semithin sections of the distal nerve segment from the recipient taken at a distance of 0.5 cm from the site of injury showed that transplantation of dissociated cells of embryonic spinal cord led to an increase in the number of myelinated nerve fibers in the recipient nerve.

Development of rat embryonic spinal ganglion cells in damaged nerve.

The development of dissociated cells from rat embryonic spinal ganglion after transplantation to damaged nerve of adult animals was studied using immunohistochemical differentiation markers of neural and glial cells. The cell suspension obtained after dissociation of rat embryonic spinal ganglia (embryonic day 15) was injected into the proximal segment of crushed sciatic nerve. The nerve was damaged by ligation for 40 sec. Progenitor cells were labeled with 5-bromo-2'-deoxyuridine (BrdU) before transplantation. BrdU-immunopositive cells were detected in the nerve trunks of recipients on days 1, 21, and 28 after transplantation. Dissociated cells of rat embryonic spinal ganglion (embryonic day 15) survived for at least 4 weeks after transplantation to the nerve and differentiate into NeuN-immunopositive neurons with morphological properties of sensory neurons and satellite cells containing S100 protein.

[Effect of embryonic anlage allografts of the rat spinal cord on growth of regenerating fibers of the recipient nerve].

A comparative study of the effect of tissue and suspension allografts of an embryonic spinal cord on regeneration of nerve fibers of impaired (by application of a ligature) sciatic nerve in rats was conducted. It was demonstrated that unlike tissue grafts that reach a large volume 21 and 60 days after transplantation, suspension grafts do not inhibit the growth of axons of the recipient to the periphery. It was established that introduction of a suspension of dissociated cells of the spinal cord embryonic anlages (but not fragments of these anlages) into the impaired sciatic nerve in rats results in an increase in the amount of myelinated regenerating nerve fibers of the recipient 60 days after the operation.

Differentiation of dissociated rat embryonic brain after allotransplantation into damaged nerve.

Fragments of the dorsolateral wall of the anterior brain vesicle from rat embryos on embryonic day 15 were dissociated and the resultant suspension containing single cells and cell aggregates was injected into the proximal segment of crushed sciatic nerve of adult animals for evaluation of their engrafting and differentiation under conditions of changed microenvironment. On days 1 and 21 postoperation, Msi-1, GFAP, NeuN, vimentin, and PCNA were detected by immunohistochemical methods. Small clusters of Msi-1-immunopositive cells were detected in the nerve trunks on the next day after transplantation. On day 21 after surgery, these precursors differentiate into nerve cells, astrocytes, and primarily ependymocytes.

[Development of dissociated cells of various rat cns primordia after transplantation into the damaged nerve].

The purpose of this paper was to examine the possibilities of engraftment, and to study the differentiation of the dissociated cells from the embryonic primordia of the spinal cord and the neocortex of Wistar rats, after their transplantation into the sciatic nerve of adult animals. The cell suspension obtained as a result of a dissociation of fragments of the cervical spinal cord and the anterior cerebral vesicle from rat fetuses at day 15 of development, was injected into the proximal segment of a previously damaged sciatic nerve. Using the immunocytochemichal marker of neural stem/progenitor cells (Msi-1) the transplanted cells were identified in the nerve trunks after 1 day after the operation. After 21 day some of these cells underwent differentiation into NeuN-immunopositive neurons, however their number was small. Thus, dissociated precursor cells from embryonic rat spinal cord and neocortex survive for three weeks under conditions of transplantation into the damaged nerve and retain the ability to differentiate into neurons, but the number is small. Most of the cells in the neocortex transplants, unlike those from spinal cord transplants, within 21 days after the operation were represented by the ependymocytes.

Effects of low-level 50 Hz magnetic fields on the level of host defense and on spleen colony formation.

The results of 3 sets of experiments on the effects of 22 microT sinusoidal 50 Hz magnetic fields (MF), applied for 1 h on 5 successive days (1 h/5 days), on the level of host defense and on spleen colony formation are reported. The first set of experiments shows the effects on the number of colony-forming units (CFUs) on the spleen and on the cellularity of the thymus in mice. The MF exposures resulted in an increase in CFUs which was statistically significant with respect to the controls, but not with respect to the shams. Statistically significant changes in the thymic weight and thymic index with respect to both the controls and the shams were measured 1 h after the last MF exposure. In the second set of experiments, the mice were given a sublethal dose of X-rays (6 Gy), which was followed by exposure 2 h later to the MF. The MF exposure was repeated at the same time of day for 5 days. The number of colonies per spleen showed a consistent, statistically significant increase with MF exposure and the number of CFUs per femur was decreased. In the third set of experiments, bone marrow was taken from mice which had been exposed to 22 microT fields and injected into mice which had been exposed to a lethal dose of X-rays (9 Gy). The number of CFUs per femur in the recipient mice was shown to be reduced by a statistically significant amount at 1 and 4 days after injection.

[Effects of syngeneic UV-irradiated blood transfusion on the hemopoietic function of the bone marrow in normal state and in craniocerebral injuries in mice]. / Vliianie perelivanii singennoi UF-obluchennoi krovi na gemopoéticheskuiu funktsiiu kostnogo mozga v norme i pri cherepno-mozgovoi travme u myshei.

Experiments on mice (CBA X C57 Bl6)F1 using endo- and exogenous cloning have shown that ultraviolet irradiation of blood enhances colony stimulating properties of plasma. Stimulation of colony formation occurs both in vitro, on direct contact of UV-irradiated blood plasma with bone marrow cells, and in vivo, upon this injection to the whole organism. In the latter case, increased migration of colony forming hematopoietic cells from the bone marrow can be noted. Single intravenous injection of syngenic UV-irradiated blood prevents inhibition of hematopoietic function of the bone marrow induced by closed brain injury.

[Differentiation and a change in the sensitivity to antibrain serum of circulating colony-forming units under the action of thymic factors]. / Differentsirovka i izmenenie chuvstvitel'nosti k antimozgovoi syvorotke tsirkuliruiushchikh kolonieobrazuiushchikh edinits pod deistviem timicheskikh faktorov.

The rabbit anti-mouse brain serum (RAMBS) that interacts with SC-1 marked cells, rather than with thymocytes and bone marrow cells, inhibits most of the blood and bone marrow colony-forming unit (CFU) population. A commercial thymus preparation thymalin increases the granulocytopoietic activity of the circulating CFU and decreases their sensitivity to RAMBS in thymectomized and normal animals. Differentiation of circulating CFU remains unchanged in thymalin-treated mice after RAMBS administration, while CFU erythroid activity of nontreated animals is lowered. The revealed changes in the CFU differentiation and sensitivity to RAMBS confirm the assumption that SC-1 antigen may mark Thy-1 lymphocytes of their microenvironment, rather than CFU.