We investigated the peripheral demyelination in transgenic mice with peripheral neuropathy and the effect of adiposederived multipotent mesenchymal stromal cells (ADSCs) transplantation on the ultrastructural features of the sciatic nerve in these mice. The B6.Cg-Tg(PMP22)C3Fbas/J transgenic mice with peripheral neuropathy were injected intramuscularly with ADSCs, which were isolated from the adipose tissue of FVB-Cg-Tg(GFPU) mice transgenic by GFP. For ultrastructural analysis, tissue fixation in animals was performed by transcardiac perfusion-fixation with 4% formaldehyde solution and 2.5% glutaraldehyde solution 16 weeks after transplantation. Electron microscopic examination of fibers of the sciatic nerve in the transgenic mice with peripheral neuropathy showed that many axons in this nerve were subjected to dys- and demyelination; the so-called onion bulb-like structures were observed. In some fibers, hypertrophy of myelin sheaths was found. In general, ultrastructural modifications in the sciatic nerve of the transgenic mice were rather similar to the pathomorphological pattern observed in patients with peripheral neuropathy. At 16 weeks after ADSC transplantation, in the sciatic nerve in mice with peripheral neuropathy thickening of the myelin sheath and increasing of the number of lamellae were observed. Thus, ADSC transplantation in mice with hereditary peripheral neuropathy has a protective effect on the ultrastructural features of the sciatic nerve and inhibits the process of axon demyelination.
Brain inflammation is a key event triggering the pathological process associated with many neurodegenerative diseases. Current personalized medicine and translational research in neurodegenerative diseases focus on adipose-derived stem cells (ASCs), because they are patient-specific, thereby reducing the risk of immune rejection. ASCs have been shown to exert a therapeutic effect following transplantation in animal models of neuroinflammation. However, the mechanisms by which transplanted ASCs promote cell survival and/or functional recovery are not fully understood. We investigated the effects of ASCs in in vivo and in vitro lipopolysaccharide (LPS)-induced neuroinflammatory models. Brain damage was evaluated immunohistochemically using specific antibody markers of microglia, astroglia and oligodendrocytes. ASCs were used for intracerebral transplantation, as well as for non-contact co-culture with brain slices. In both in vivo and in vitro models, we found that LPS caused micro- and astroglial activation and oligodendrocyte degradation, whereas the presence of ASCs significantly reduced the damaging effects. It should be noted that the observed ASCs protection in a non-contact co-culture suggested that this effect was due to humoral factors via ASC-released biomodulatory molecules. However, further clinical studies are required to establish the therapeutic mechanisms of ASCs, and optimize their use as a part of a personalized medicine strategy.
Traumatic brain injury (TBI) is accompanied by an increase in the number of proliferating cells. However, the question of the nature, conditions of production and mechanisms of action of humoral factors secreted by fetal neural cells (FNCs) on reparative processes and neurogenesis in the brain after trauma and FNCs transplantation remains open. The purpose of the study was to establish the possibility of the influence of the conditioned medium of fetal neural cell cultures on the proliferative activity of Ki-67-positive cells in the cortex and subcortical structures of the rat brain after TBI. Materials and methods. TBI was simulated by dropping a metal cylinder on the rat’s head. Rats (E17-18) were used to obtain cultures of neural stem/progenitor cells. Conditioned media from cell cultures with high adhesive properties (HA-CM) and low adhesive properties (LA-CM) were used to treat the effects of experimental TBI in rats by intramuscular injection. The effect of conditioned media on the proliferative activity of Ki-67-positive cells in the cortex and subcortical structures of the brain after TBI was determined by immunohistochemical analysis using antibodies against Ki-67 protein. Results. Immunohistochemical analysis of the brain sections showed that on the 5th day after traumatic brain injury in rats there was a probable increase in the number of Ki-67-positive cells in the cortex, hippocampus and thalamus. It was found that the injection of HA-CM or LA-CM in animals with TBI increased the number of Ki-67-positive cells in the hippocampus compared with the TBI group and their value for the TBI+LA-CM group reached 59.6 ± 6.1, and for the TBI+HA-CM group – 47.2 ± 3.1 cells (p <0.05 compared with the TBI group). In the cortex and thalamus, the number of Ki-67-positive cells in contrast decreased compared with the group of animals with TBI and for the group TBI+LA-CM was 20.2 ± 1.6 and 12.0 ± 1.7, respectively, and for the group TBI+HA-CM – 25.3 ± 2.1 and 13.3 ± 1.3, respectively. Conclusions. The administration of LA-CM or HA-CM to animals with traumatic brain injury increases the number of Ki-67-positive cells in the hippocampus, possibly associated with increased neurogenesis, and decreases in the cortex and thalamus, which may be due to a weakening of reactive gliosis.
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