Long-distance axonal regeneration in the transected adult rat spinal cord is promoted by olfactory ensheathing glia transplants (original) (raw)
Related papers
Journal of Neurotrauma, 2003
The aim of this study was to determine the preferred time and environment for transplantation of olfactory ensheathing glia (OEG) into the moderately contused adult rat thoracic spinal cord. Purified OEG were suspended in culture medium with or without fibrinogen and injected into the contused cord segment at 30 min or 7 days after injury. Control animals received a contusion injury only or injection of only medium 7 days after contusion. The effects on axonal sparing/regeneration and functional recovery were evaluated 8 weeks after injury. The grafts largely filled the lesion site, reducing cavitation, and appeared continuous with the spinal nervous tissue. Whereas in 7d/medium only animals, 54% of spinal tissue within a 2.5-mm-long segment of cord centered at the injury site was spared, significantly more tissue was spared in 0 d/OEG-medium (73%), 0 d/OEG-fibrin (66%), 7 d/OEG-medium (70%), and 7 d/OEG-fibrin (68%) grafted animals. Compared with controls, the grafted animals exhibited more serotonergic axons within the transplant, the surrounding white matter, and the spinal cord up to at least 20 mm caudal to the graft. Retrograde tracing revealed that all but the 0 d/OEG-fibrin graft promoted sparing/regeneration of supraspinal axons compared with controls. Overall, the 7 d/OEG-medium group resulted in the best response, with twice as many labeled neurons in the brain compared with 7 d/medium only controls. Of the labeled neurons, 68% were located in the reticular formation, and 4% in the red, 4% in the raphe, and 5% in the vestibular nuclei. Hindlimb performance was modestly but significantly improved in the 7 d/OEG-medium group. Our results demonstrate that transplantation of OEG into the moderately contused adult rat thoracic spinal cord promotes sparing/regeneration of supraspinal axons and that 7 d transplantation is more effective than acute transplantation of OEG. Our results have relevant implications for future surgical repair strategies of the contused spinal cord.
Olfactory ensheathing cells promote collateral axonal branching in the injured adult rat spinal cord
2004
In recent years, injection of olfactory ensheathing cells (ECs) into the spinal cord has been used as an experimental strategy to promote regeneration of injured axons. In this study, we have compared the effects of transplanting encapsulated ECs with those injected directly into the spinal cord. The dorsal columns of adult rats were cut at T 8 -9 and rats in experimental groups received either EC-filled porous polymer capsules or culture medium (CM)-filled capsules with ECs injected at the injury site. Control rats were in three groups: (1) uninjured, (2) lesion with transplantation of CM-filled capsules and (3) lesion with transplantation of CM-filled capsules and injections of CM. Three weeks after injury, Fluororuby was injected into the hindlimb motor and somatosensory cortex to label corticospinal neurons. Observations indicated that there were a few regenerating fibres, up to 10, in the EC-treated groups. In rats that received encapsulated ECs, regenerating fibres were present in close association with the capsule. Rats that received EC injections demonstrated a significant increase in the number of collateral branches from the intact ventral corticospinal tract (vCST) compared with the corresponding control, CM-injected group ( P = 0.003), while a trend for increased collateral branches was observed in rats that received encapsulated ECs ( P = 0.07).
Experimental Neurology, 2006
Cellular transplantation, including olfactory ensheathing cells (OEC) and olfactory nerve fibroblasts (ONF), after experimental spinal cord injury in the rat has previously resulted in regrowth of severed corticospinal (CS) axons across small lesion gaps and partial functional recovery. In order to stimulate CS axon regrowth across large lesion gaps, we used a multifactorial transplantation strategy to create an OEC/ONF continuum in spinal cords with a 2-mm-long dorsal hemisection lesion gap. This strategy involved the use of aligned OEC/ONF-poly(D,L)lactide biomatrix bridges within the lesion gap and OEC/ONF injections at 1 mm rostral and caudal to the lesion gap. In order to test the effects of this complete strategy, control animals only received injections with culture medium rostral and caudal to the lesion gap. Anatomically, our multifactorial intervention resulted in an enhanced presence of injured CS axons directly rostral to the lesion gap (65.0 ± 12.8% in transplanted animals versus 13.1 ± 3.9% in control animals). No regrowth of these axons was observed through the lesion site, which may be related to a lack of OEC/ONF survival on the biomatrices. Furthermore, a 10-fold increase of neurofilament-positive axon ingrowth into the lesion site as compared to untreated control animals was observed.
Glia, 2007
Schwann cells (SCs) and olfactory ensheathing glia (OEG) have shown promise for spinal cord injury repair. We sought their in vivo identification following transplantation into the contused adult rat spinal cord at 1 week post-injury by: (i) DNA in situ hybridization (ISH) with a Y-chromosome specific probe to identify male transplants in female rats and (ii) lentiviral vector-mediated expression of EGFP. Survival, migration, and axon-glia association were quantified from 3 days to 9 weeks post-transplantation. At 3 weeks after transplantation into the lesion, a 60–90% loss of grafted cells was observed. OEG-only grafts survived very poorly within the lesion (<5%); injection outside the lesion led to a 60% survival rate, implying that the injury milieu was hostile to transplanted cells and or prevented their proliferation. At later times post-grafting, p75+/EGFP− cells in the lesion outnumbered EGFP+ cells in all paradigms, evidence of significant host SC infiltration. SCs and OEG injected into the injury failed to migrate from the lesion. Injection of OEG outside of the injury resulted in their migration into the SC-injected injury site, not via normal-appearing host tissue but along the pia or via the central canal. In all paradigms, host axons were seen in association with or ensheathed by transplanted glia. Numerous myelinated axons were found within regions of grafted SCs but not OEG. The current study details the temporal survival, migration, axon association of SCs and OEG, and functional recovery after grafting into the contused spinal cord, research previously complicated due to a lack of quality, long-term markers for cell tracking in vivo. © 2007 Wiley-Liss, Inc.
Tissue Engineering and Regenerative Medicine, 2016
Traumatically injured central nervous system (CNS) forms a hostile environment to axon regeneration and repair via cell and tissue destruction caused by the initial insult, followed by a cascade of secondary pathophysiological events including the increased expression of certain axon growth-repulsive chondroitin sulphate proteoglycans during scarring, the presence of myelin debris and the formation of cystic cavitation [1-3]. Many studies have shown that CNS axon regeneration can take place after traumatic injury provided that an appropriate growth-promoting substrate has been implanted into the lesion site [4]. Cell transplantation-based repair strategies have demonstrated the implantation of donor cells to be an effective means for importing growth promoting factors/substrates into lesioned tissues. A number of cell types, including neural and non-neural stem cells, neural progenitors, Schwann cells (SC), astrocytes, oligodendrocytes, olfactory ensheathing cells (OECs) and activated macrophages have, so far, been investigated in experimen
2011
Spinal Wistar Hannover rats injected with olfactory ensheathing glia (OEG) have been shown to recover some bipedal stepping and climbing abilities. Given the intrinsic ability of the spinal cord to regain stepping with pharmacological agents or epidural stimulation after a complete midthoracic transection, we asked if functional recovery after OEG injections is due to changes in the caudal stump or facilitation of functional regeneration of axons across the transection site. OEG were injected rostral and caudal to the transection site immediately after transection. Robotically assisted step training in the presence of intrathecal injections of a 5-HT 2A receptor agonist (quipazine) was used to facilitate recovery of stepping. Bipedal stepping as well as climbing abilities were tested over a 6-month period post-transection to determine any improvement in hindlimb functional due to OEG injections and/or step training. The ability for OEG to facilitate regeneration was analyzed electrophysiologically by transcranially stimulating the brainstem and recording motor evoked potentials (MEP) with chronically implanted intramuscular EMG electrodes in the soleus and tibalis anterior with and without intrathecal injections of noradrenergic, serotonergic, and glycinergic receptor antagonists. Analyses confirmed that along with improved stepping ability and increased use of the hindlimbs during climbing, only OEG rats showed recovery of MEP. In addition the MEP signals were eliminated after a re-transection of the spinal cord rostral to the original transection and were modified in the presence of receptor antagonists. These data indicate that improved hindlimb function after a complete transection was coupled with OEG-facilitated functional regeneration of axons.
Molecular Therapy, 2006
Immortalized cell lines of olfactory ensheathing glia (OEG) that maintain the proregenerative properties of primary cultures provide an unlimited source of OEG for both basic and applied studies. Indeed, one specific immortalized rat OEG clonal line (TEG3) proved to be as good as primary OEG in promoting neuritogenesis and axon regeneration in culture models. Thus, we examined the capacity of TEG3 to promote axonal repair in an animal model of spinal cord injury, dorsal column crush. TEG3 cells can acquire astrocyte-like or Schwann cell-like morphology depending on the conditions under which they are cultured. In the injured spinal cord, prelabeled TEG3 survived for at least 10 weeks after grafting and they integrated into the spinal cord, adopting Schwann cell-like, astrocyte-like, or intermediate morphologies. In TEG3-transplanted animals, sensory projection axons grow into the lesion site and there was robust sprouting/axonal growth of the corticospinal tract, both into and beyond the lesion site, after crushing of the spinal cord-dorsal columns. TEG3-transplanted animals also recovered sensory and motor function in tape removal and beam walking behavioral tests. These data indicate that certain immortalized cell lines derived from a single cell can maintain the regenerative properties of primary OEG.
Glia, 2003
We studied the effects of olfactory ensheathing cells (OECs) transplanted in a photochemical spinal cord injury in adult rats. After dorsal laminectomy at T8 vertebra, subjacent spinal cord was bathed with rose Bengal for 10 min and illuminated with visible light by means of an optic fiber connected to a halogen lamp for 2.5 min at maximal intensity of 8 kLux. Eight injured rats received a suspension of OECs in DMEM, and another eight rats received DMEM alone. Locomotor ability scored by the BBB scale, pain sensibility by the plantar algesimetry test, and motor-and somatosensory-evoked potentials by electrophysiological techniques were evaluated for 3 months postsurgery. Finally, all rats were perfused with paraformaldehyde and transverse sections from the spinal cord segment at the lesion site were immunostained against GFAP. Area of the preserved spinal cord parenchyma was measured from the GFAPimmunolabeled cord sections. The BBB score and the amplitude of motor-and somatosensory-evoked potentials were higher in OECs-transplanted rats than in DMEMinjected animals throughout follow-up, whereas the withdrawal response to heat noxious stimulus was lower in OEC-than in DMEM-injected rats. The area of preserved spinal cord was significantly larger in OECs-transplanted rats than in DMEM-injected animals. These results indicate that OECs promote functional and morphological preservation of the spinal cord after photochemical injury. GLIA 42: [275][276][277][278][279][280][281][282][283][284][285][286] 2003.
Transplanted olfactory ensheathing cells promote regeneration of cut adult rat optic nerve axons
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2003
Transplantation of olfactory ensheathing cells into spinal cord lesions promotes regeneration of cut axons into terminal fields and functional recovery. This repair involves the formation of a peripheral nerve-like bridge in which perineurial-like fibroblasts are organized into a longitudinal stack of parallel tubular channels, some of which contain regenerating axons enwrapped by Schwann-like olfactory ensheathing cells. The present study examines whether cut retinal ganglion cell axons will also respond to these cells, and if so, whether they form the same type of arrangement. In adult rats, the optic nerve was completely severed behind the optic disc, and a matrix containing cultured olfactory ensheathing cells was inserted between the proximal and distal stumps. After 6 months, the transplanted cells had migrated for up to 10 mm into the distal stump. Anterograde labeling with cholera toxin B showed that cut retinal ganglion cell axons had regenerated through the transplants, en...