The European journal of neuroscience
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Comparative Study
Bone marrow mesenchymal stromal cells and olfactory ensheathing cells transplantation after spinal cord injury--a morphological and functional comparison in rats.
Cell therapy for spinal cord injury (SCI) is a promising strategy for clinical application. Both bone marrow mesenchymal stromal cells (MSCs; also known as bone marrow-derived 'mesenchymal stem cells') and olfactory ensheathing cells (OECs) have demonstrated beneficial effects following transplantation in animal models of SCI. However, due to the large number of affecting parameters that determine the therapy success and the lack of methodological consensus, the comparison of different works is difficult. ⋯ Despite the low survival of the cells, MSC and OEC grafts provided tissue protection after early and delayed transplantation. Nevertheless, only acute MSC grafts improved locomotion recovery in treadmill condition and electrophysiological outcomes with respect to the other injured groups. These results, together with previous works, indicate that the MSC seem a better option than OEC for treatment of contusion injuries.
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Members of the miR-183 family are unique in that they are highly abundant in sensory organs. In a recent study, significant downregulation was observed for miR-96 and miR-183 in the L5 dorsal root ganglion (DRG) 2 weeks after spinal nerve ligation (SNL). In this study, we focused on miR-183, which is the most regulated member of the miR-183 family, to look at the specific role on neuropathic pain. ⋯ Intrathecal administration of lentivirions expressing miR-183 downregulated SNL-induced increases in the expression of Nav1.3 and brain-derived neurotrophic factor (BDNF), which correlated with the significant attenuation of SNL-induced mechanical allodynia. Our results show that SNL-induced mechanical allodynia is significantly correlated with the decreased expression of miR-183 in DRG cells. Replacement of miR-183 downregulates SNL-induced increases in Nav1.3 and BDNF expression, and attenuates SNL-induced mechanical allodynia.
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NMDA receptors in primary afferent terminals can contribute to hyperalgesia by increasing neurotransmitter release. In rats and mice, we found that the ability of intrathecal NMDA to induce neurokinin 1 receptor (NK1R) internalization (a measure of substance P release) required a previous injection of BDNF. Selective knock-down of NMDA receptors in primary afferents decreased NMDA-induced NK1R internalization, confirming the presynaptic location of these receptors. ⋯ Patch-clamp recordings showed that BDNF, but not proBDNF, increased NMDA receptor currents in cultured DRG neurons. NMDA-induced NK1R internalization was also enabled in a neuropathic pain model or by activating dorsal horn microglia with lipopolysaccharide. These effects were decreased by a BDNF scavenger, a trkB receptor antagonist and a Src family kinase inhibitor, indicating that BDNF released by microglia potentiates NMDA receptors in primary afferents during neuropathic pain.