Affiliations: Department of Anatomy and Neurobiology, Kyoto
University Graduate School of Medicine, Yoshidakonoe-cho, Sakyo-ku, Kyoto
606-8501, Japan | Department of Anatomy | Electron Microscopic Laboratory, Iwate Medical
University, Uchimaru 19-1, Morioka 020, Japan | Seishin Nursing School, Katsunari 78-73, Kannde-cho, Nishi-ku, Kobe 651-2301, Japan
Note: [] Correspondence to: Chizuka Ide, Department of Anatomy and
Neurobiology, Kyoto University Graduate School of Medicine, Yoshidakonoe-cho,
Sakyo-ku, Kyoto 606-8501, Japan.
Abstract: Axonal and glial reactions to traumatic injury were compared between
the caudal and rostral border of the lesion after freeze-injury to the C3
dorsal funiculus by attaching a liquid nitrogen-cooled copper probe to the
dorsum of the rat spinal cord. The axonal and glial changes were examined up to
60 days postoperative by light and electron microscopy and immunohistochemistry
for neurofilaments. Regenerative axonal changes and the appearance of numerous
undifferentiated cells were found at the caudal border 7 days after cryoinjury.
In contrast, such axonal and cellular reactions were scarce at the rostral
border. Undifferentiated cells clearly manifested their phenotypes by
differentiating into oligodendrocytes or astrocytes 11 days postinjury. The
results indicated that glial cell reactions occurred in association with
regenerative axonal changes at the proximal stump of the injured nerve fibers,
suggesting that regenerating and demyelinated naked axons could be responsible
for the appearance of the immature glial cells.
