Spinal cord injury (SCI) is a commen desease in clinic. We mainly introduced some trends on research of SCI. Especially, some challenging questions were primarily discussed in this paper.

BACKGROUND: The free radicals induced by cerebral ischemia/reperfusion consist mainly of xanthine oxidase, which induces cell swelling in the infarcted area.OBJECTIVE: To observe the changes of cerebral ischemia/reperfusioninduced changes in the activity of cerebral superoxide dismutase (SOD), an enzyme responsible for free radical clearance, and investigate the effect of apurin, a inhibitor of purine oxidase, on cellular water content in the brain tissue with ischemia/reperfusion injury.DESIGN: Completely randomized controlled study.SETTING: Department of Neurology of the Central Hospital Affiliated to Shenyang Medical College, Department of Neurosurgery of the First Hospital Affiliated to China Medical University, and Liaoning Provincial Orthopedic Hospital for Limb Disabilities.MATERIALS: The experiment was conducted in the Laboratory of the Central Hospital Affiliated to Shenyang Medical College from May 2003 to April 2004. Forty Wistar rats were subjected to a 6-hour cerebral ischemia and randomized into 4 equal groups to receive intragastric administration of 100 mg/kg apurin (ischemia + apurin group), oxolinic acid suspension of the same dose (ischemia+ oxolinic acid group), 100 mg/kg apurin after a 2-hour reperfusion (Ischemia/reperfusion + apurin group), or oxolinic acid of the same dosage after the 2-hour reperfusion (ischemia/reperfusion + oxolinic acid goup), respectively. The rats in apurin group had intragastric administration of 100 mg/kg apurin 48, 24 and 1 hour before occlusion of the cervical internal carotid artery (CICA) to induce the ischemia, respectively. Oxolinic acid was given in the two oxolinic acid groups in the same manner.METHODS:Water content of brain tissue of rats was measured after 6 hours of CICA occlusion in the two ischemia groups and after the 2-hour perfusion in the two ischemia/reperfusion groups. Distribution of SOD in the brain tissue was observed with SOD immunostaining.MAIN OUTCOME MEASURES: Distribution of SOD and water content in the brain tissue of rats.RESULTS: In the two oxolinic acid groups, Cu-Zn SOD staining identified obviously increased staining intensity in the ischemic foci. Mn SOD staining in ischemia+oxolinic acid group resulted in increased circular staining surrounding the vessels in the ischemic foci, with also obvious staining of the vascular wall and neural cells. The ischemic foci of the ischemia/reperfusion + oxolinic acid group showed diffuse but lightly weaker staining. Cu-Zn SOD staining in the two apurin groups revealed no significant difference. In the two oxolinic acid groups, endothelial cell nuclear swelling of the arteriole, protrusion of the mid-layer myocytes, and expansion of the vascular membrane were observed, with the tissues surrounding the vessels appearing spongy. These changes were less severe in the two apurin groups. The water content in the brain tissue was (78.56±0.30) % in ischemia + apurin group and (78.85±0.49) % in ischemia/reperfusion + apurin group, significantly lower than that of (79.08±0.33) % in ischemia + oxolinic acid group and (79.86±0.49) % in ischemia/reperfusion + oxolinic acid group (P ＜ 0.05).CONCLUSION: Apurin can relieve tissue injury after cerebral ischemia/reperfusion by inhibition of SOD.

TrkB was designated as the functional receptor of br ain derived neurotrophic factor． In these study, we investigated the distributi on of trkB-like immunoreactivity(trkB-IR) in spinal cord of adult cats using spe cific antiserum for trkB by immunohistochemistry ABC method． The results were a s following: trkB-IR was mainly distributed in neurons of spinal cord including ventrolateral horn, intermedius are and dorsal horn． 　　 The subcellular localization of positiveproduct was mainly in cytoplasm． Our results provided morphological evidence on the distribution of trkB in spinal cord of adult cats． It indicated the role o f trkB involve in physiological function of spinal cord of adult cat．

AIM: The aim of this study was to explore the expression of nerve growth factor(NGF) in spinal dorsal horn following crushed spinal cord injury. METHODS: The adult Srague-Dawley rat model of crushed spinal cord injury was established by the method in our laboratory, and intact spinal cord was used as control. The rats were sacrificed respectively after 24 hours, 7 days, and 21 days of operation, and the L3 spinal segments were removed out and fixed in 4% polyformaldehyde. The segments were sectioned into sections of 20 μm in thickness. The sections were stained with anti-NGF antibody by ABC method of immunohistochemistry technique. The immunoreactive intensity of NGF and the number of positive neurons as well as glial cells in dorsal horn were observed and counted under light microscope. RESULTS: The number of positive cells and immunoreactive intensity of NGF increased gradually in the dorsal horn at 24 hours, 7 days and 21 days following crushed spinal cord injury compared with control group (P＜0.01). CONCLUSION: These results indicated that NGF plays an important role in the postoperative reaction during the early period of the crushed spinal cord injury.

AIM: It is well known that different injuries will result in different consequences. In this paper, we investigated the morphological change of spinal cord following crushed, hemi-sectioned and transected injury. METHODS: Sixty Wistar rats were randomly divided into 4 groups: intact group, crushed spinal cord injury group (cSCI), hem-sectioned SCI group (hSCI) and transitioned SCI group (tSCI). The models of SCI were established by the method in our laboratory. The animals in each group were sacrificed respectively at 24 hours, 7 and 24 days after operation. The L2 spinal cord which located in the caudal of injury site was taken respectively from each animal in each group and sectioned into frozen sections (20 μm). The sections were stained by hematoxylin and observed under light microscope. The number of neurons in dorsal and ventral horn was also counted. RESULTS: In cSCI group, some neurons appear to atrophy compared with that of intact group, but the number of neurons did not decrease apparently than that of intact group (P＞0.05). Comparatively, some cavities were observed in dorsal and ventral horn in hemi-sectioned and transitioned SCI group. And the number of neurons in dorsal horn and ventral horn decreased greatly at 24 hours, 7 and 21 days compared with intact group (P＜0.05). The results indicated that the decrease of neuronal number in dorsal horn and ventral horn after injury resulted from hSCI and tSCI, but not from cSCI. As a result, some different strategies should be considered for different injuries. For example, some neurotrophic factors may be useful in cSCI, but, many neurons have disappeared following hSCI and tSCI, therefore, other strategies that increase the number of neurons should be considered too. CONCLUSION: Our results provide the important morphological evidences on the change of spinal cord following cSCI, hSCI and tSCI. The data will be useful in treatment of SCI in the future.

ObjectiveTo study the effect of bone mesenchymal stem cells (BMSC) transplantation into traumatic brain injury(TBI) rats by the external carotid artery on neurological function and learning and memory.MethodsTen adult SD rats were randomly divided into TBI group ( n =5 ) and BMSC transplantation group ( n=5).Feeney free falling method was used to establish TBI models.The experimental rats were administrated with BMSC via external carotid artery (ECA),while TBI rats were injected with sterile liquid medium of equal volume via right ECA.Neurological function were evaluated according to the modified neurological severity score (NSS) at 1,3,7,15 days.Morris water maze test was used to observe the animal capabilities of place navigation and space exploration at 15 days,then animals were sacrificed.Survival and migration of implanted BMSC in brains under fluorescence microscope. ResultAfter traumatic brain,varying degrees convulsions,paralysis,loss of balance function in rats were found.Compared with TBI group,BMSC transplantation decreased significantly NSS (P ＜0.01 ).BMSC transplantation significantly decreased on escape latency ( ( 20.48 ± 2.29 ) s ) than the TBI group ( ( 85.93 ± 47.48 ) s) (P ＜ 0.01 ).Moreover,BMSC group in the target quadrant dwell time ( ( 28.62 ± 1.72) ％ )and distance ( (29.05 ± 3.08 )％ ) as well as the number of passing the platform (8.00 ± 2.45 ) were significantly higher than the TBI group ( ( 19.37 ± 2.81 ) ％,(21.78 ± 3.06) ％,(2.00 ± 1.87) respectively,P ＜ 0.01 ).Transplanted BMSC could survive and migrate around injury brain through Hochest mark immunofluorescence.ConclusionBMSC can survive and migrate around injury brain by transplantation of external carotid artery,which results in a significant neurological function improvement and learning and memory increase in rats with traumatic brain injury.

To explore the characteristic features of morpho logical changes of neurons in the spinal dorsal horn result from different types of spinal cord in jury, the adult Srague-Daweley fat models of crushed, hemi-sected and transected spinal cord injury established in our laboratory were used, and the intact spin al cords were as control． 　　These rats were sacrificed after 24 hours, 7 days and 2l days of operation, and the L3, segments were removed out and sectioned continuously into sections of 20 μm in thickness． The sections were stained by hematoxylin and observed under ． 　　 microscope． In addition, neurons in the dorsal horn were counted． 　　 Results: In the crushed spinal horns, bodies of neurons were atrophy, but neuron counting did not decrease markedly; in the hemi-sected and transected dorsal horn, a batch of empty cavities were presented, and neuron counting decreased greatly． The results indicated that different injuries of spinal cord resulted in different damage to neurons in the dorsal horn, i． e． the crushed one, the bad, the hemi-sected one, the worse; and the transected one, the worst．

Objective To evaluate the curative effect and value of dilatation technique with double balloon in the treatment of cardia achalasia.Methods 52 patients with cardia achalasia were treated by the dilatation technique with double balloon.Results The effective rate was 100% in short term while.In long term,the effective rate was 96% and 100% with one time dilatation and double time dilatations respectively.Conclusion The dilatation technique with double balloon is a safe,effective and easy operated method in the treatment of cardia achalasia.

Objective To establish a serial of stable and mature methods of primary culture hippocampus neurons of GFP-transgene embryonic mice,to get the morphologic data of cultured neurons.Based on this research,in future,we can give an important theoretical and practical support for the therapy of nervous system diseases by transplanting with hippocampus neurons of GFP-transgene embryonic mice.Methods We primarily cultured the hippocampus neurons derived from the GFP-transgene embryonic mice in vitro.Under the microscope,we found cultured hippocampus neurons could live for more than one month and appeared to be the best status in 5～7 d after culture.During this time,the processes of the neurons are thick and the neurons connected one another to form the"cells-net" through their processes.After 14 d,the growth of the hippocampus neurons became slow.Results A serial of culture methods of hippocampus neurons had been successfully established.These cultured neurons were identified by the immuno-histochemical methods.They grow well in different phases before 14 d after culture.Conclusion Culturing hippocampus neurons of GFP-transgene embryonic mice is a simple,stable and effective method which can be applied to scientific research by other researchers.

Objective To isolate the bone marrow mesenchymal stem cells(MSCs) from the GFP-expressing mouse, and to study the osteoblastic differentation of the cells. Methods MSCs were isolated by density gradient centrifugation, then the clutrued cells were induced to osteoblastic differentiation using the conditional medium. We detectd the expression of GFP and MSCs differentiation into osteoblasts by histochemistry and immunochemistry. Results The MSCs maintained the expression of GFP during expanded and induced process. After induced for 10 days, lots of alkaline phosphatase and osteoclcin staining positive cells were observed.Conclusion The MSCs of GFP-expressing mouse were successfully isolated and differentiated into ostoblasts. It may be valuable for tracing the seeding cells in tissue engineering bone.