Abstract
The process of regeneration of rat dorsal root ganglion cells was investigated by scanning and transmission electron microscopy and compared with the process of in vitro neurite formation. After disruption of the granular reticulum, numerous microtubules appeared in the perinuclear cytoplasm. Many thin, regenerating nerve fibers were found at the suture line adjacent to collagen fibers. Subsequently, the number of cytoplasmic neurofilament bundles increased and many of the regenerated nerves attached to the suture line. By the eighth week after experimental injury, the granular reticulum had reconstituted in the cytoplasm and the regenerated nerves resembled those of control animals, although the fiber arrangement was somewhat irregular. The process was almost identical to that of in vitro neurite formation, although the time course was much slower. Structural proteins, such as actin, tubulin, and neurofilament triplet, appeared to form similarly in neuronal regeneration and in vitro neurite formation. The results also suggest that microtubules are essential for nerve regeneration as well as neurite formation and that components of the neuronal microenvironment, such as collagen fibers and migrating cells, play crucial roles in nerve regeneration.
