[Autophagic effect of Schwann cells in the regeneration of rat sciatic nerves].
OBJECTIVE
To investigate the autophagic effect of Schwann cells in the process of rat sciatic nerve regeneration.


METHODS
Wallerian degeneration model was established by transecting the rat sciatic nerve. Samples from the distal stump were obtained 0, 0.5, 1, 1.5, 2, 3, 4, 5, 7, 10, and 15 days respectively after the transaction, and ultrathin sections were prepared for examination with electron microscope.


RESULTS
Axons started to separate from the myelin sheath at day 0.5 after the transection, followed by rapid vacuolar degeneration. Since day 2, the myelin sheath folded and broke into fragments, and in the Schwann cells large cell membrane-bound myelin debris and many scattered small fragments could be seen to fuse with the lysosomes to form ACPase reaction-positive autophagic vacuoles. Immature cells were occasionally seen in the endoneural space, appearing in large amount a week later. After day 7, the number of autophagic vacuoles began to diminish. In the entire course of the observation, macrophages containing autophagic vacuoles, were spotted only occasionally.


CONCLUSIONS
The degenerated myelin debris are cleared mainly through the mechanism of autophagy by the Schwann cells during regeneration of rat sciatic nerve. Schwann cells dedifferentiate into Schwann cell precursors, which then proliferate and differentiate to take part in the regeneration of the nerves.
Wang
Wan-shan
WS
Department of Anatomy, First Military Medical University, Guangzhou 510515, China. wangwanshan@yahoo.com
Piao
Zhong-xian
ZX
Han
Ming-hu
MH
Wang
Qi-wei
QW
Piao
Ying-jie
YJ
D000818:Animals; D002454:Cell Differentiation; D005260:Female; D008297:Male; D009186:Myelin Sheath / Q000473:pathology; D009416:Nerve Regeneration; D010587:Phagocytosis; D051381:Rats; D017208:Rats, Wistar; D012583:Schwann Cells / Q000166:cytology / Q000502:physiology*; D012584:Sciatic Nerve / Q000502:physiology*; D014855:Wallerian Degeneration / Q000473:pathology*