Résumé
BACKGROUND: Transplantation of microencapsulated rabbit Schwann cells in the rat spinal cord can relieve inflammatory reaction, promote spinal cord regeneration, but the precise mechanisms remain unclear. OBJECTIVE:To observe basic fibroblast growth factor (bFGF)expression and movements recovery following transplantation of microencapsulated rabbit Schwann cells in rat spinal cord. METHODS: The sciatic nerves taken out from rabbits wore digested with mixed enzyme and were made into Schwann cells suspension. Then we used air-jet method to make Schwann cells microcapsule. Using the same method, empty microcapsule was made. Sprague Dawiey rats were randomly divided into cell group, empty microcapsule group and microcapsule group. Conducted by hemisection injury of spinal cord,the rats in cell group,empty microcapsule group and microcapsule group were implanted with gelatin sponge with 10μL Schwann cells suspension, gelatin sponge with 10 μL empty microcapsule and 10 μL microencapsulated Schwann cells. Normal group was left intact. After operation, we observed hindlimb movements recovery in rats with the Basso, Beattie, and Bresnahan (BBB) scale. Meanwhile,a set of sections were stained immunohistochemically for bFGF expression, another set of sections wore stained for hematoxylin-eosin and Nissal. RESULTS AND CONCLUSION: After spinal cord injury, rat right hindlimb affected paralysis immediately. At 7, 14 and 28 daysfollowing transplantation,motor function in rat hindlimb was significantly recovered, and the BBB scores were significantly higher in microencapsulated schwenn cells than in cell and empty microcapsule group (P < 0.05 or P < 0.01). bFGF positive products were mainly distributed in cytoplasm of the spinal neuron and nucleus of neuroglical cell. The numbers of bFGF positive glial cells mainly appeared surrounding the spinal cord injured site on days 1, 3, 7 and rose to its peak on day 3 and began to appear in neuronal calls on day 14. The number of bFGF positiv cells in microcapsule group was significantly superior to that in cell group and empty microcapsule group. From then on, the bFGF expreSsion was significantly decreased in each group. These indicated that transplantation of microencapsulated Schwann cells can inhibit the immunological rejection after xenotransplantation, suppress inflammatory reaction, improve the expression of bFGF, increase hindlimb movements recovery and spinal cord regeneration after spinal cord injury.
Résumé
OBJECTIVE: To summarize the effects of glial cell line-derived neurotrophic factor (GDNF) on ischemia damage to nerve tissue and discuss the possibility of GDNF in repair of spinal cord injury based on the development of microencapsulation technology.DATA SOURCES: A search of Medline from January 1996 to October 2000 was performed for the English articles related to GDNF, ischemia damage to nerve tissue, spinal cord injury and microencapsulation technology by using the key words "glial cell line-derived neurotrophic factor, ischemia damage to nerve tissue, spinal cord injury". Meanwhile, we retrieved Wangfang database for search of the related articles in Chinese by using the same keywords in Chinese.STUDY SELECTION: Articles including intervention group and control group were selected after first review, and those which were significantly non-randomized researches were excluded. Then, the full-texts of the enrolled articles were retrieved. Inclusion criteria: ①randomized controlled study; ②the experiment/clinical research including horizontal control group. Exclusion criteria: duplicated researches.DATA EXTRACTION: Totally 300 articles were selected but only 15 were in coincidence with conclusion criteria. 285 articles were excluded, 264 of them were duplicated and non-randomized researches, and 21 were review articles.DATA SYNTHESIS: GDNF can provide nutrition to dopamine nerve cell in rat's middle brain, so as to decrease dopamine nerve cell's death. Also GDNF can protect dopamine nerve cell in cerebral infarction rats from ischemic injury, inhibit the produce of nitrogen monoxide and reperfusion injury after ischemia. GDNF is an effective protective factor against ischemia damage. Microencapsulation technology has a bright future in treating endocrinopathic neural diseases, and GDNF can play a great role in the development of microencapsulation technology.CONCLUSION: GDNF is a protective factor against ischemia damage to nerve tissue, which can be enhanced by microencapsulation technology.There is a bright future for the research on GDNF in the clinical repair of spinal cord injury.