The Biological Characteristics Of Olfactory Ensheating Cell And Long Term Experimental Survey At Its Transplantion To Acute Spinal Cord Injury

It has been proven that the olfactory ensheating cells (OECs) can promote the regeneration of spinal cord axons by excreting several factors and forming myelin sheathes for regenerating axons. There were some experiments about the functional recovery of OECs transplantation on the complete spinal cord transection, semisection and electrolytic lesions, but there were little research on observing long term functional recovery. Objective: One of the aims was to study the biological characteristic in vitro. The other was to observe the long term results of OECs survival and repair in vivo for spinal cord contusion after the OECs transplantation.Methods: 1. In vitro study: The neurons were co-cultured with OECs in vitro. After 24 hours, the cultures were prepared for anti-neurofilement-200 immunostaining as well as image analysis to get average and the longest length of axon for one neuron and the neurons survival.2. In vivo study: The T13 spinal cords contusion of 2.5 months Wistar rats was made with the NYU impactor in Group A and Group B. OEG labeled by Hoechst was transplanted in group A (20 rats). In group B (20 rats), DMEM were injected. In Group C (10 rats), T13 laminectomies were done without cord contusion. The functional recovery of the spinal cord injury was observed with BBB locomotion score in each double week. The retrograde labeling study with flurogold were done 6 months postoperatively. The HE staining and silver staining were also performed respectively to observe the pathological changes and axon regeneration. The survival of OECs, which was labeled by Hoechst, wasobserved under the fluorescence microscope. Results:1. While the neurons co-cultured with OECs, the average and longest length of axon for all neurons, and neuron survinal were significantly longer than the neurons cultured alone.2. The experiment showed that locomotion behaviour had improved 6 weeks postoperatively. The BBB locomotion score of group A is higher than that of group B in all periods. The functional recovery appeared a platform at 16 weeks postoeratively (BBB locomotion score about 10).3. Nerve fiber innervated injury area in the group A and B. In the cephal lesion, the number of nerve fibers of group A was more than that of group B(P(0.001), but less than that of group C(P(0.001). 4. In group A, the number of nerve fiber of the caudal lesions was less than that of the cephal lesion(P(0.001). In the group B, there were few nerve fibers in the caudal part of lesion.5. A great number of OEG labeled by Hoechst were observed around spinal injury area through the fluorescence microscope. 6. There were abundant labeled neurons in the superior part of CNS including the intermediate zone and dorsal column of lower thoracic spinal cord,the upper thoracic, cervical spinal cord, reticular nucleus and raphe nucleus as well as reticular nucleus and parabrachial nucleus of pons.Conclusion:1. In vitro, OECs can survive and stimulate the neurons.2. After transplantation, OECs can survive for at least 6 months in vivo, and can migrate from the injection sites.3. For spinal cord contusion, OEG can promote the axons regeneration and the little recovery of locomotion function in our study.