Olfactory ensheathing cells transplanted in lesioned spinal cord prevent loss of spinal cord parenchyma and promote functional recovery.

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 GFAP-immunolabeled cord sections. The BBB score and the amplitude of motor- and somatosensory-evoked potentials were higher in OECs-transplanted rats than in DMEM-injected 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.

Verdú E ，García-Alías G ，Forés J ，López-Vales R ，Navarro X ... -  《GLIA》

Acute transplantation of olfactory ensheathing cells or Schwann cells promotes recovery after spinal cord injury in the rat.

We compared the neurological and electrophysiological outcome, glial reactivity, and spared spinal cord connectivity promoted by acute transplantation of olfactory ensheathing cells (group OEC) or Schwann cells (group SC) after a mild injury to the rat spinal cord. Animals were subjected to a photochemical injury of 2.5 min irradiation at the T8 spinal cord segment. After lesion, a suspension containing 180,000 OECs or SCs was injected. A control group (group DM) received the vehicle alone. During 3 months postsurgery, behavioral skills were assessed with open field-BBB scale, inclined plane, and thermal algesimetry tests. Motor (MEPs) and somatosensory evoked potentials (SSEPs) were performed to evaluate the integrity of spinal cord pathways, whereas lumbar spinal reflexes were evaluated by the H reflex responses. Glial fibrillary acidic protein and proteoglycan expressions were quantified immunohistochemically at the injured spinal segments, and the preservation of corticospinal and raphespinal tracts caudal to the lesion was evaluated. Both OEC- and SC-transplanted groups showed significantly better results in all the behavioral tests than the DM group. Furthermore, the OEC group had higher MEP amplitudes and lower H responses than the other two groups. At the injury site, the area of spared parenchyma was greater in transplanted than in control injured rats. OEC-transplanted animals had reduced astrocytic reactivity and proteoglycan expression in comparison with SC-transplanted and DM rats. Taken together, these results indicate that transplantation of both OEC and SC has potential for restoration of injured spinal cords. OEC grafts showed superior ability to reduce glial reactivity and to improve functional recovery.

García-Alías G ，López-Vales R ，Forés J ，Navarro X ，Verdú E ... -  《JOURNAL OF NEUROSCIENCE RESEARCH》

Increased expression of cyclo-oxygenase 2 and vascular endothelial growth factor in lesioned spinal cord by transplanted olfactory ensheathing cells.

Olfactory ensheathing cells (OECs) were transplanted in adult rats after photochemical injury of the spinal cord. Rats received either 180,000 OECs suspended in DMEM or DMEM alone. Locomotor ability scored by the BBB-scale, pain sensibility, and motor and somatosensory evoked potentials were evaluated during the first 14 days post-surgery. At 3, 7, and 14 days, 5 rats per day of both groups were perfused and transverse sections from proximal, lesioned and distal spinal cord blocks were stained for COX-2, VEGF, GFAP and lectin. The BBB-score and the amplitude of motor and somatosensory evoked potentials were significantly higher in OEC- than in DMEM-injected animals throughout follow-up, whereas the withdrawal latency to heat noxious stimulus was lower in OEC- than in DMEM-injected rats. The area of preserved spinal cord and the levels of COX-2 and VEGF staining were significantly higher in OEC- than in DMEM-injected rats. GFAP- but no LEC-positive cells expressed COX-2 staining in OEC-transplanted rats. The density of blood vessels was also significantly increased in OEC- with respect to DMEM-injected rats. Our results show that OECs promote functional and morphological preservation of the spinal cord after photochemical injury, increasing neoangiogenesis and up-regulation of COX-2 and VEGF expression in astrocytes.

López-Vales R ，García-Alías G ，Forés J ，Navarro X ，Verdú E ... -  《JOURNAL OF NEUROTRAUMA》

Olfactory ensheathing cells can reduce the tissue loss but not the cavity formation in contused spinal cord of rats.

In recent years, olfactory ensheathing cells (OECs) have been used as a therapeutic strategy to repair the anatomical structure and promote the function recovery of injured spinal cord in both animal and human. In this study, OECs were transplanted into contused spinal cords of adult rats. After dorsal laminectomy at T10 vertebra, spinal cord was injured by a force of 10 g with NYU II impactor from 25 mm above the exposed cord. The contused spinal cord received injections of OECs in DMEM or DMEM alone at one week after injury. The migration and distribution of OECs in the contused spinal cord were observed by the light microscope. The intact tissue area, injured tissue area, cavity size, number of myelinated nerve fibers and neurons labeled by CB-HRP in T8 segment were measured and counted by the semi-quantitative techniques at 6 weeks after transplantation. Locomotor ability and conductive function of the spinal cord were evaluated by the BBB score and cortical somatosensory evoked potentials (CSEP) recording. OECs were found in both lesion site and tissue near the lesion. The intact tissue area was significantly larger in the OECs-transplanted rats than that in the DMEM-injected animals, whereas the injured tissue area was significantly smaller in the OECs-rats than that in the DMEM-rats. The number of myelinated nerve fibers in the lesion site and preserved neurons in T8 was significantly greater in the OECs-group than in the DMEM-group, but the cavity size detected was not significantly different between the two groups. The BBB score and CSEP recording showed a better performance of locomotor ability and conductive function in the OECs-transplanted rats than in the DMEM-injected animals. These results indicate that OECs can counteract secondary tissue degeneration after spinal cord injury. Although they cannot reduce the cavity formation, they can promote morphological preservation and functional improvement of the contused spinal cord.

Li BC ，Li Y ，Chen LF ，Chang JY ，Duan ZX ... -  《-》

Chronic transplantation of olfactory ensheathing cells promotes partial recovery after complete spinal cord transection in the rat.

The goal of this study was to ascertain whether olfactory ensheathing cells (OECs) were able to promote axonal regeneration and functional recovery when transplanted 45 days after complete transection of the thoracic spinal cord in adult rats. OECs promoted partial restitution of supraspinal pathways evaluated by motor evoked potentials and modest recovery of hindlimb movements. In addition, OEC grafts reduced lumbar reflex hyperexcitability from the first month after transplantation. Histological results revealed that OECs facilitated corticospinal and raphespinal axons regrowth through the injury site and into the caudal spinal cord segments. Interestingly, raphespinal but not corticospinal fibers regenerated long distances through the gray matter and reached the lower lumbar segments (L5) of the spinal cord. However, delayed OEC grafts failed to reduce posttraumatic astrogliosis. In conclusion, the beneficial effects found in the present study further support the use of OECs for treating chronic spinal cord injuries.

López-Vales R ，Forés J ，Navarro X ，Verdú E ... -  《GLIA》