Zucker C L, Ehinger B, Seiler M, Aramant R B, Adolph A R
Schepens Eye Research Institute, Boston, MA.
J Neural Transplant Plast. 1994 Jan-Mar;5(1):17-29. doi: 10.1155/NP.1994.17.
The development of five transplants of fetal retinal tissue to adult rat eyes was examined with the electron microscope. The transplants were of 9 to 10 weeks total age after conception in four cases and 20 weeks in one case. They were at stage E15 when transplanted. Transplants developed in both the epiretinal and subretinal spaces. The transplants were heterogeneously developed with some parts showing almost normal differentiation and others little. Subretinal transplants examined in this study were more developed than epiretinal grafts. Photoreceptor cells developed both inner and outer segments. Their synaptic terminals possessed output ribbon synapses with postsynaptic processes similar to those seen in normal retinas. In regions corresponding to the inner plexiform layer, the adult complement of synapses was seen, including advanced features such as serial synapses as well as reciprocal synapses at bipolar cell dyads. Incompletely differentiated synapses of both the amacrine and bipolar cell types were often observed, especially in the rat epiretinal transplants. Ganglion cell processes could not be identified with certainty. Although transplant cells were adjacent to host photoreceptor cells and pigment epithelium, obvious specializations or interactions were not observed. The experiments suggest that embryonic rat retinal cell transplants develop most or perhaps all of the structural components and neuronal circuitry necessary to transduce light and process some visual information.
用电子显微镜检查了将五块胎儿视网膜组织移植到成年大鼠眼中的发育情况。其中四例移植组织受孕后的总年龄为9至10周，一例为20周。移植时处于胚胎第15期。移植组织在视网膜前间隙和视网膜下间隙均有发育。移植组织发育不均一，有些部分显示出几乎正常的分化，而有些部分则很少。本研究中检查的视网膜下移植组织比视网膜前移植组织发育得更好。光感受器细胞发育出内节和外节。它们的突触终末具有输出带状突触，其突触后过程与正常视网膜中所见的相似。在对应于内网层的区域，可见成年期的突触结构，包括串联突触以及双极细胞二分体处的交互突触等高级特征。常观察到无长突细胞和双极细胞类型的不完全分化突触，尤其是在大鼠视网膜前移植组织中。无法确切识别神经节细胞的突起。尽管移植细胞与宿主光感受器细胞和色素上皮相邻，但未观察到明显的特化或相互作用。这些实验表明，胚胎大鼠视网膜细胞移植发育出了大部分或可能所有将光转化并处理一些视觉信息所需的结构成分和神经回路。
