L-type calcium channel antagonist nifedipine reduces neurofilament restitution following traumatic optic nerve injury.

BACKGROUND

The aim of the present study was to observe if the use of the L-type calcium channel antagonist nifedipine would offer advantages for the retinal ganglion cells and the restitution of the axonal cytoskeleton after optic nerve crush.

METHODS

Retinal ganglion cells were retrogradely labeled with a fluorescent calcium marker. With the in vivo confocal neuroimaging (ICON) method we observed the fluorescent cell metabolism marker Oregon Green BAPTA in the same retinal ganglion cells over 3 weeks after optic nerve crush. 2 micromol nifedipine were injected intraocularly 30 minutes following optic nerve crush.

FINDINGS: Investigation of the optic nerve immunostained for NF-H presented decreased restitution of the neurofilaments in the axonal cytoskeleton after 3 weeks in the optic nerve crush group treated with nifedipine as compared to the optic nerve crush only group.

INTERPRETATION: These results show that a single injection of the calcium L-type antagonist nifedipine shortly after optic nerve injury has long-lasting negative effects on the recovery of the retinal ganglion cells.