胚胎海马伞移植物对成年大鼠海马胆碱能纤维生长的引导效应

在胚胎和新生的中枢神经系统(CNS)内,发育中的纤维束通道能引导轴突的生长。为了了解发育中的纤维束通道能否引导成年CNS轴突的生长,将胚胎海马伞移植到成年大鼠的海马,两周后,用AChE组织化学方法检查移植物内的胆碱能纤维。结果如下:在胚胎的海马伞移植物内出现大量的胆碱能纤维,但在成年的海马伞移植物内没有宿主的胆碱能纤维长入;如果在移植胚胎海马伞的同时,切断宿主的海马伞-穹窿通路,则在胚胎移植物和宿主海马内均无胆碱能纤维;将胚胎海马伞作成悬浮液进行移植,在移植部位,仅能看到少数长的胆碱能纤维;但是若把胚胎海马伞的组织碎片粘附在硝化纤维素滤纸条周围,再移植到成年大鼠海马内,来自宿主海马的大量胆碱能纤维被吸引围绕着滤纸条并沿其表面生长。结果似乎表明:胚胎海马伞或胚胎海马伞碎片都能有效引导宿主海马胆碱能纤维的生长。因此,胚胎海马伞和其它发育中的CNS纤维束通道可能是引导成年CNS轴突生长的良好天然基质。

GUIDING EFFECT OF EMBRYONIC FIMBRIA GRAFT ON CHOLINERGIC FIBER GROWTH IN HIPPOCAMPUS OF ADULT RATS

In view of the fact that in embryonic and neonatal central nervous system(CNS), the pathway of developing fiber tracts is capable of guiding the axonalgrowth, it would be interesting to know whether a similar effect exists on the ax-onal growth in adult CNS. Embryonic fimbria was grafted into the hippocampusof the adult rat. Two weeks later. the grafts were examined for cholinergic fiberswith AChE histochemical method. It was found that a lot of cholinergic fibersappeared in the embryonic graft, but none of them in the adult fimbria graft ascontrol. If the fimbria-fornix was transected at the time of grafting, no cholinergicfibers could subsequently be detected in both the embryonic graft and the hosthippocampus. If a suspension of embryonic fimbria was used as a graft, only afew of long cholinergic fibers could be found in the grafted area. However, if tissuefragments of embryonic fimbria adhered to a strip of nitrocellulose filter were graf-ted as previously, numerous cholinergic fibers from the host hippocampus werefound to be attracted around the strip and grow along the surface of the filter.The results seem to indicate that grafted embryonic fimbria or its tissue fragmentsare able to guide cholinergic fiber growth in adult hippocampus. It is possiblethat embryonic fimbria and other pathways of developing CNS fiber tracts providea natural substrate for guiding axonal growth in adult CNS.