Study On Olfactory Ensheathing Cells Vein Graft For Treatment Of Spinal Cord Injury

Spinal cord injury (SCI), as one of the most difficult diseases, is clinically commonand highly disabling. It is difficult to treat. Unfortunately, there is no routine treatment.Olfactory ensheathing cell (OECs) graft can promote nerve to repair and axon toregenerate after spinal cord injury in research, which has been recognized as the mostpromising ones in the treatment of spinal cord injury. The previous study has confirmedthat the vein graft of olfactory ensheathing cells can treat spinal cord injury, and the effectis similar to the effect of local graft. In this study, we explored the effects of olfactoryensheathing cell graft in the treatment of acute and old spinal cord injury. we revealed thecorrelation between the efficacy of vein graft of olfactory ensheathing cells for curingspinal cord injury and the dose of the transplanted cells. And also, we explored the efficacyof olfactory ensheathing cell graft in the treatment of old spinal cord injury. This study willprovide theoretical foundation for the clinical application of olfactory ensheathing cellgraft in the treatment of acute and old spinal cord injury.Part1STUDIES ON DIFFERENT DOSES OF OLFACTORY ENSHEATHING CELLS INVEIN GRAFT FOR TREATMENT OF ACUTE SPINAL CORD INJURY.Objective:To explore the correlation between the efficacy and the dose of the graft cells, andexplore the optimal dose of cells.Methods:1. Primary culture, purification, identification and labeling of OECs:The wistar rats were anesthesized successfully. Then the whole olfactory bulb wasremoved and cut into pieces.Then they were cultured according to the modified Nashattachment method in combination with the Ara-c suppression method. The cultured cellswere identified with NGFRp75and GFAP. After digestion, the cells were harvested, labled with benzylidene methylamine, and were counted under the microscope.2. Preparation and grouping of the animal model with spinal cord injury：The wistar rats were pepared into the model of T10left side of the spinal cordhemisection injury. Then they were randomly divided into5groups: vein graft by highdoses of OECs group(Group A), vein graft by medium doses(Group B), vein graft by lowdoses(Group C), D/F12cell culture medium graft group (Group D), and blank controlgroup (Group E).3. Evaluation of the recovery of the neurological function：The spinal cord nerve function recovery of1d,1w,2w,3w,4w,6w,8w, and10w aftergraft was evaluated by scoring the rat hind limb motor and sensory functions according tothe Combined Behavioral Score (CBS score) method respectively.2rats in each group of4weeks and10weeks after graft were randomly selected for spinal cord tissue collection.The collected tissues were sliced by HE staining and silver staining. The scar formationand axon regeneration of nerve fibers in the region with spinal cord injury were monitoredand recored. The survival and distribution of the OECs in the SCI region was detected byimmunohistochemical staining of the nerve growth factor receptor NGFRp75.Results:According to the CBS scores, there is significant differences between Group A/B andGroup C/D/E at each time point from the second week (p <0.05). No significant differencewas shown neither between Group D and Group E (p>0.05), or between Group A andGroup B (p>0.05). Small difference between Group C and Group D/E was shown.According to the microscopic observation of morphological changes in the spinal cordinjury sites, Group A and Group B have more nerve fiber axon regeneration, which couldpass the scar tissues of the injury site partly. Group C, Group D, and Group E only have avery small amount of nerve fiber axon regeneration, which couldn’t pass the scar tissues ofthe injury site. Significant differences were shown between Group A/B and Group C/D/E.No significient difference was shown neither between Group D and Group E, or betweenGroup A and Group B. The recovery of spinal cord function of Group A/B was much betterthan Group C/D/E, and Group C was better than Group D/E.Conclusion:The vein graft of OECs has a certain effect for the treatment of acute spinal cordinjury, and the effect is positively correlated with the cell dose in a certain range. Theoptimal dose of olfactory ensheathing cells is2×106. Part2STUDY ON THE TREATMENT OF OLD SPINALCORD INJURY BY OECS GRAFT.Objective:To explore the efficacy and feasibility of OECs graft in the treatment of old spinalcord injury.Methods:The wistar rats were prepared into the model of the T10left side of the spinal cordhemisection injury. These rats were allowed for self-healing for1month without anytreatment. When the recovery of the spinal function became slow and went into a plateau,CBS score was made, in which each rat was scoring47. Then the rats were randomlydivided into3groups（10each group）: vein graft group of olfactory ensheathing cells(Group F), D/F12cell culture medium graft group (Group G), blank control group (GroupH). The recovery of spinal function was evaluated by the CBS score and histologicalexamination.Results:According to the CBS scores, significant differences were shown between Group Fand Group G/H at each time point from the second week (p <0.05). No significantdifference was shown between Group G and Group H (p>0.05).According to the microscopic observation of morphological changes in the spinal cordinjury sites, significant differences were shown between Group F and Group G/H. Group Fhas smaller scar tissues and more nerve fiber axon regeneration than Group G/H, whichshows better spinal cord recovery.Conclusion:The vein graft of olfactory ensheathing cells has a certain effect for the treatment ofold spinal cord injury.