Effects of transplanting olfactory ensheathing cells on recovery of olfactory epithelium after olfactory nerve transection in rats.
BACKGROUND
Olfactory ensheathing cells (OECs) can remyelinate injured spinal cord and the peripheral nerve system, but little is known about its effect on the transected olfactory nerve. We investigated recovery of olfactory epithelium after transplanting allogeneic OECs in transected rat olfactory nerves.


METHODS
Olfactory ensheathing cells from the olfactory bulb were cultured in DMEM/F-12 medium and purified with cytosine arabinoside (Ara-c). Forty Sprague-Dawley rats were divided into 2 groups; the left olfactory nerve was transected in all animals. In the transplant group, DiI-labeled OECs were injected into the gap between the dura and the cribriform plate (n=24); DMEM/F-12 medium was injected in control animals (n=16). Rats were subsequently killed for histologic examination. Olfactory evoked potentials (OEPs) were used to evaluate nerve conduction.


RESULTS
After transecting the olfactory nerve, there was no horseradish peroxidase staining in the olfactory bulb; some OEPs disappeared. Five days after surgery, there was no horseradish peroxidase staining in the olfactory bulb of any animal. Apoptotic cells appeared in the epithelium; the thickness and cell number of the olfactory epithelium were decreased. Two weeks later, the thickness and cell number of the olfactory epithelium increased gradually. Some horseradish peroxidase staining in the olfactory bulb and OECs was detected; more growth associated protein-43 marked olfactory receptor neurons were visible. Six weeks after surgery, the cell number was greater in the transplant group (P<0.05); there was no statistically significant between-group difference regarding olfactory epithelium thickness.


CONCLUSIONS
Transplanted OECs may be used to treat transected olfactory nerves.
Wei
Yongxiang
Y
Department of Otolaryngology Head and Neck Surgery, Beijing Institute of Otolaryngology, Key laboratory of Otolaryngology Head and Neck Surgery (Ministry of Education), Beijing Tongren Hospital, Capital Medical University, Beijing 100730, P.R. China.
Miao
Xutao
X
Xian
Mu
M
Zhang
Cong
C
Liu
Xiaochao
X
Zhao
Hong
H
Zhan
Xiaojun
X
Han
Demin
D
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002478:Cells, Cultured; D020287:In Situ Nick-End Labeling; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology*; D009830:Olfactory Bulb / Q000166:cytology / Q000637:transplantation; D009831:Olfactory Mucosa / Q000473:pathology / Q000502:physiology*; D009832:Olfactory Nerve / Q000502:physiology / Q000601:surgery; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley