Effect of neurotrophic factor and stem cell therapy on axonal regeneration after spinal cord injury: Overseas progress in basic and clinical researches / 中国组织工程研究

ABSTRACT

BACKGROUND: Now, progress has been made in understanding the pathomechanisms, protection of injured neurons,regeneration of oligodendrocytes and transplantation of neural stem cells. This paper is aimed to introduce the decade progression, latest research and novel therapies in the area of spinal cord injury internationally.DATA SOURCES Related articles published from January 1987 to October 2006 were chosen from the America Medline Database, and the language was limited to English, with the search keywords of "spinal cord injury; neural stem cells;axon; neurotrophic factor and animal model".STUDY SELECTION After the primary trial, the full versions of the articles related to neural stem cell and neurotrophic factor were reviewed according to the following criterias ① experiments investigating the mechanisms and novel therapies of spinal cord injury. ②papers revealing the axon regeneration, function of growth cone, targets for inducting the regeneration direction as well as synapse and function rebuild. ③ papers reporting neurotrophic factor and endogenous stem cell therapies. Excluded criteria ①papers with lower impact factor in SCl or studies with similar results.②papers without English abstract.DATA EXTRACTION A total of 1 166 papers were found in Medline, 101 papers accord with the above criteria, 61 papers were cited in this review, including 12 papers for the mechanism of spinal cord injury, 14 papers for axon regeneration, 8 papers for the function of growth cone, 8 papers for the oligodendrocytes, 7 papers for neural stem cells and the left 12 papers for neurotrophic factor. Other articles were deleted.DATA SYNTHESIS: ①Base of functional recovery after spinal cord injury The regeneration and elongation of damaged axons; The capacity of axons to penetrate the scar; Re-growth in the direction of appropriate target .regions; Cessation of axonal growth, formation of terminal arbors and formation of synaptic contacts with target neurons; The restoration of functional neurotransmission and the recovery of function.②Neuropathological analysis of spinal cord injury the primary and secondary damage after spinal cord injury.③Molecular biological mechanism of spinal cord injury The growth cone is important for the establishment of neural circuitry during neural development and regeneration in the adult CNS after injury; Central nerve system myelin protein is inhibitory for axonal growth; cell membrane and intracellular signal transmission. ④The important cells and cytokine of spinal cord injury oligodendrocyte, leukemia inhibitory factor,minocycline and endogenous neural stem cells. ⑤Animal models of spinal cord injury The most common models are total transactions, partial transections and contusions. ⑤Prospect of researches on spinal cord injury The therapy of neurotrophic factor and neural stem cell has been transformed to clinical practice, for example, the leukaemia inhibitory factor has been applied on clinical experiment at Ⅳ phase, and the research of the induction and proliferation of ndogenous stem cells has been paid much more attention.CONCLUSION: The regeneration of spinal cord after injury is becoming possible using the therapies of neurotrophic actor and neural stem cell. It would be an ideal direction in the near future to investigate the mechanisms of axon regeneration induced by neurotrophic factor intervention in the research areas of spinal cord injury. It would also play a vital role to reveal the proliferation and differentiation of endogenous neural stem cells in repairing the injury of spinal cord.