Axonal regeneration induced by repetitive electrical stimulation of crushed optic nerve in adult rats.
OBJECTIVE
To investigate whether electrical stimulation promoted axonal regeneration of retinal ganglion cells (RGCs) after optic nerve (ON) crush in adult rats.


METHODS
Transcorneal electrical stimulation (TES), which stimulates the retina with current from a corneal contact lens electrode, was used to stimulate the eye. TES was applied for 1 h immediately after ON crush. Axonal regeneration was determined by anterograde labeling of RGC axons. To examine whether the axonal regeneration was mediated by insulin-like growth factor 1 (IGF-1) receptors, an IGF-1 receptor antagonist, JB3, was injected intraperitoneally before each TES application. Immunostaining for IGF-1 was performed to examine the effects of TES. To test the survival-promoting effects of TES applied daily, the mean density of retrogradely labeled RGCs was determined on day 12 after ON crush.


RESULTS
Compared with sham stimulation, the mean number of regenerating axons significantly increased at 250 microm distal from the lesion and increased IGF-1 immunoreactivity was observed in retinas treated daily with TES. Preinjection of an IGF-1 receptor antagonist significantly blocked axonal regeneration by TES applied daily. TES applied daily also markedly enhanced the survival of RGCs 12 days after ON crush.


CONCLUSIONS
TES applied daily promotes both axonal regeneration and survival of RGCs after ON crush.
Tagami
Yuichi
Y
Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.
Kurimoto
Takuji
T
Miyoshi
Tomomitsu
T
Morimoto
Takeshi
T
Sawai
Hajime
H
Mimura
Osamu
O
D000818:Animals; D001369:Axons / Q000502:physiology*; D002452:Cell Count; D002470:Cell Survival; D004599:Electric Stimulation Therapy; D019084:Fluorescent Antibody Technique, Indirect; D007334:Insulin-Like Growth Factor I / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D009409:Nerve Crush; D009416:Nerve Regeneration / Q000502:physiology*; D020221:Optic Nerve Injuries / Q000378:metabolism / Q000503:physiopathology*; D051381:Rats; D017208:Rats, Wistar; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000502:physiology*; D015854:Up-Regulation
C096150:insulin-like growth factor-1 D peptide; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1