Effect of intrathecal injection of stem cells derived from human umbilical cord blood after spinal cord ischemic injury.

Abstract

The protection of the spinal cord remains as the most controversial and problematic aspect of the surgery of the thoracic aorta and thoracoabdominal aorta In spite of the progresses reached with the development of new techniques of spinal cord protection, the paraplegia continues coming as one of the main complications in the aorta surgeries. The left atrium - femoral artery bypass, the cerebrospinal fluid drainage, the identification of the adamckievicz artery and its implant are technical established that decreased in an important way the paraplegia incidence in the surgeries of the descending thoracic aorta. The use of the evoked potential in the surgeries of the aorta is also winning space in the sense of contributing the identification of spinal cord injury during the operative action. Furthermore, the evoked potential has been used in the development of new techniques of spinal cord protection as, for instance, the acute ischemic preconditioning, developed recently by our group. Studies regarding the use of stem cells in chronic and traumatic injuries of spinal cord have already been accomplished in experimental environment and in clinical use. Some positive aspects have been observed in the results of the cellular therapy in traumatic injuries of spinal cord. The presence of neovascularization and the recovery, even that partially, of the somatosensory evoked potential are some examples of this answer. In respect to the cellular therapy in the spinal cord ischemic injury, there are not too many studies, and still exist many doubt regarding which would be the best cell type to be used (mesenquimal, embryonic), which the appropriate concentration to be administered and no less discussed, which the best administration way. However, to example of the therapy in the initial traumatic injury, experimental studies show signs that the cellular therapy can bring some benefit in the ischemic injury of spinal cord. Our objective is to evaluate the effect of the intratecal injection of stem cells derived from human umbilical cord blood in acute ischemic injury of the spinal cord in rats. We will use 48 Wistar rats that the sharp ischemic of the spinal cord will be submitted by the occlusion of the descending thoracic aorta. With the insert of a catheter type fogarty n.2 in the left common carotid artery it will be insufflate ties that there is the occlusion of the aorta. With control of the proximal arterial blood pressure (carotid artery) and distal (tail artery) in relationship occlusion, the ischemia will be promoted by a period of 10 min. being proven for the important fall of the distal pressure and for the loss of the evoked potential. After the period of the aorta occlusion, the animal will be stabilized of the point of view hemodynamic and the incisions closed. Six groups will be accomplished. In all of the groups the complete procedure of aorta occlusion will be accomplished. In the first group, one hour before the ischemia period, we will infuse in intratecal space 1x107 stem cells derived from human umbilical cord blood. In the second group, the cells will be infused one hour after the ischemia and in the third group; the administration will be made six hours after the ischemia. The concentration of cells will be the same in all of the groups: The other three groups will just be their respective controls with the administration of the infusion vehicle. The recovery of of hind limb motor function will be assessed every week during six weeks by the BBB scale. At the end of the period, the animals will be submitted the euthanasia and transcardially perfused. The spinal cords will be dissected and postfixed for histological study, immunohistochemistry and western-blot analysis. It will be analyzed the number of necrotic and viable neurons through hematoxilina and eosina. For the apoptose we will analyse the proteins of the BCL-2 family, citocrom-C and caspase 3. (AU)