Legendre D I, Vietje B P, Wells J
University of Vermont, Burlington 05405.
Exp Neurol. 1994 Feb;125(2):247-57. doi: 10.1006/exnr.1994.1027.
Immature cells transplanted into an adult host must adapt to their new environment. In the present study we have shown the dendritic development of dentate granule cells following transplantation. The adult host granule cells were lesioned by a fluid injection into the infragranular cleavage plane of the dentate gyrus. Few, if any, granule cells survived the lesion and the molecular layer (ML) shrank. When allogeneic neonatal granule cells were included in the fluid, the host granule cells were simultaneously killed and replaced. In order to visualize the dendrites, the granule cells were filled with Lucifer yellow (LY) in fixed sections and subsequently immunoreacted with an antibody to LY. The granule cell dendrites in the transplant were shorter in length, had a greater cross-sectional area, had more spines, and were more coiled and bent than control granule cell dendrites. The dendrites in the transplant formed functional synapses as indicated by cytochrome oxidase histochemistry and the transplant prevented xc03some of the ML shrinkage. Acetylcholinesterase (ACHE) xkreaction product increased both in lesioned and in transplant groups. The laminar pattern of ACHE in the control ML was not seen after the lesion and did not return in animals with successful transplants. We conclude that (i) the dendrites of neurons in the transplant adapted to the adult host environment and a shrinking ML with remarkable structural plasticity; (ii) the transplant prevented some of the shrinkage of the ML; (iii) the transplant could not reverse some of the lesion-induced changes in host organization, such as the organization of ACHE inputs to the ML; and (iv) a phenotypically specific population of transplanted neurons can replace traumatically lesioned neurons of the same type even if the host conditions continue to change.
移植到成年宿主中的未成熟细胞必须适应新环境。在本研究中，我们展示了移植后齿状颗粒细胞的树突发育情况。通过向齿状回颗粒下层裂平面注射液体来损伤成年宿主的颗粒细胞。损伤后几乎没有颗粒细胞存活，分子层（ML）萎缩。当将同种异体新生颗粒细胞包含在液体中时，宿主颗粒细胞会同时被杀死并被替代。为了观察树突，在固定切片中用荧光黄（LY）填充颗粒细胞，随后用抗LY抗体进行免疫反应。与对照颗粒细胞树突相比，移植中的颗粒细胞树突长度更短、横截面积更大、有更多棘突，并且更卷曲和弯曲。如细胞色素氧化酶组织化学所示，移植中的树突形成了功能性突触，并且移植阻止了ML部分萎缩。损伤组和移植组的乙酰胆碱酯酶（ACHE）反应产物均增加。损伤后在对照ML中所见的ACHE层状模式在成功移植的动物中未恢复。我们得出以下结论：（i）移植中神经元的树突适应了成年宿主环境以及萎缩的ML，具有显著的结构可塑性；（ii）移植阻止了ML的部分萎缩；（iii）移植无法逆转宿主组织中一些由损伤引起的变化，例如向ML的ACHE输入组织；（iv）即使宿主条件持续变化，表型特异性的移植神经元群体也可以替代相同类型的创伤性损伤神经元。
