NT-3mRNA分子杂交在胚胎脊髓修复成鼠受损脊髓过程中的变化

为了从神经营养因子角度探讨移植修复机理，将大鼠１４ｄ胚胎脊髓（ＥＳＣ）植入急性损伤成鼠脊髓后１、３、５、７、１０、１５和３０ｄ，用原位杂交和斑点杂交技术对ＥＳＣ和宿主脊髓（ＨＳＣ）内ＮＴ－３ｍＲＮＡ的变化进行定性和定量观察。定性观察显示，在正常脊髓内，ＮＴ－３ｍＲＮＡ以前角运动神经元和少量胶质细胞分布为主；脊髓损伤以后，杂交产物扩大到中小型神经元，同时更多的胶质细胞参与了反应；ＥＳＣ植入后，除移植物本身继续表达外，宿主脊髓阳性反应神经元和胶质细胞数量进一步增加。定量结果表明，损伤组原位杂交和斑点杂交的反应强度明显高于正常组；而移植组的分子杂交反应又在很多时相点上显著高于损伤组。除此而外，分子杂交反应在损伤组和移植组内持续的时间也不相同，前者的最强反应期为术后７ｄ，后者为术后１０～１５ｄ．我们认为，移植的ＥＳＣ除为自身和ＨＳＣ提供神经营养外，也诱发了ＨＳＣ在发生过程中曾经拥有的合成机制，以增强ＮＦ表达的方式为自身再生提供营养，同时也为移植物的发育分化提供合适的营养环境。

CHANGES OF NT 3 mRNA BY MOLECULAR HYBRIDIZATION DURING EMBRYONIC SPINAL CORD REPAIRING SPINAL CORD INJURY OF ADULT RATS

In order to study the mechanism of transplantation and repairing from the view of neurotrophines,on days 1,3,5,7,10,15,and 30 after E14 embryonic spinal cord being transplanted into the acutely injured spinal cord of adult rats,changes of NT 3 mRNA within donor tissue and host tissue were demonstrated qualitatively and quantitatively by in situ hybridization and dot hybridation.Meantime,normal spinal cord and simply injured spinal cord were used as controls.It was shown qualitatively that NT 3 mRNA was mainly expressed within cytoplasm of motor neurons and a few gliocyte in normal spinal cord;After spinal cord injury,hybridizing products expended to the medium and small sized neurons,also more gliocytes took part in hybridization response;Following transplantation,positively hybridizing neurons and gliocytes became more in number in the host tissue,and embryonic spinal cord kept an expressing level similar to that before being transplanted.It was also revealed quantitatively that reacting intensity of the cells in the injured group was strikingly higher than that in the normal group.However hybridization intensity in the transplanted group was even higher at many intervals than that in the injured group;Besides these,the lasting period for hybridization reaction of the transplanted group was also different from that of the injured group.The most intensive reacting phase in the former presented at dya 10 and 15,and in the latter at day 7 after operation .We suggest that transplanted embryonic spinal cord can,besides providing neurotrophic factors for itself and host spinal cord,evoke synthetic mechanisms of host spinal cord once holding during its embryonic development so as to enhance expression of the neurotrophic factors.In this way,the host spinal cord might provide neurotrophic factors for its regeneration and provide an trophic environment for the grafts to develop and differentiate.