与脊髓损伤.doc

1: Age-related differences in the local cellular and molecular responses to injuryin developing spinal cord of the opossum, Monodelphis domestica. 研究发育负鼠短尾猊脊髓局部细胞和分子损伤在年龄相关性的差别 Eur J Neurosci. 2007 Mar;25(6):1725-42.Lane MA, Truettner JS, Brunschwig JP, Gomez A, Bunge MB, Dietrich WD,Dziegielewska KM, Ek CJ, Vandeberg JL, Saunders NR. Department of Pharmacology Centre for Neuroscience, University of Melbourne,Victoria, Australia. Immature spinal cord, unlike adult, has an ability to repair itself following injury. Evidence for regeneration, structural repair and development of substantially normal locomotor behaviour comes from studies of marsupials due to their immaturity at birth. We have compared morphological, cellular and molecular changes in spinal cords transected at postnatal day (P)7 or P14, from 3 h to 2weeks post-injury, in South American opossums (Monodelphis domestica). A bridge between severed ends of cords was apparent 5 days post-injury in P7 cords,compared to 2 weeks in P14. The volume of neurofilament (axonal) material in the bridge 2 weeks after injury was 30% of control in P7- but 10% in P14-injured cords. Granulocytes accumulated at the site of injury earlier (3 h) in P7 than in P14 (24 h)-injured animals. Monocytes accumulated 24 h post-injury and accumulation was greater in P14 cords. Accumulation of GFAP-positive astrocytes at the lesion occurred earlier in P14-injured cords. Neurites and growth cones were identified ultrastructurally in contact with astrocytes forming the bridge. Results using mouse inflammatory gene arrays showed differences in levels of expression of many TGF, TNF, cytokine, chemokine and interleukin gene families. Most of the genes identified were up-regulated to a greater extent following injury at P7. Some changes were validated and quantified by RT-PCR. Overall, the results suggest that at least some of the greater ability to recover from spinal cord transection at P7 compared to P14 in opossums is due to differen