Chronic intravitreous infusion of ciliary neurotrophic factor modulates electrical retinal stimulation thresholds in the RCS rat.
OBJECTIVE
To determine whether the sustained intravitreous delivery of CNTF modulates cortical response thresholds to electrical retinal stimulation in the RCS rat model of retinal degeneration.


METHODS
Animals were assigned to four groups: untreated, nonsurgical control and infusion groups of 10 ng/d CNTF, 1 ng/d CNTF, and PBS vehicle control. Thresholds for electrically evoked cortical potentials (EECPs) were recorded in response to transcorneal electrical stimulation of the retina at p30 and again at p60, after a three-week infusion.


RESULTS
As the retina degenerated over time, EECP thresholds in response to electrical retinal stimulation increased. Eyes treated with 10 ng/d CNTF demonstrated significantly greater retinal sensitivity to electrical stimulation when compared with all other groups. In addition, eyes treated with 1 ng/d CNTF demonstrated significantly greater retinal sensitivity than both PBS-treated and untreated control groups.


CONCLUSIONS
Retinal sensitivity to electrical stimulation was preserved in animals treated with chronic intravitreous infusion of CNTF. These data suggest that CNTF-mediated retinal neuroprotection may be a novel therapy that can lower stimulus thresholds in patients about to undergo retinal prosthesis implantation. Furthermore, it may maintain the long-term efficacy of these devices in patients.
Kent
Tiffany L
TL
Department of Ophthalmology, Kresge Eye Institute, Ligon Research Center of Vision, Wayne State University, 4717 St. Antoine, Detroit, MI 47201, USA.
Glybina
Inna V
IV
Abrams
Gary W
GW
Iezzi
Raymond
R
D000818:Animals; D020934:Ciliary Neurotrophic Factor / Q000008:administration & dosage*; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D007263:Infusions, Parenteral; D051381:Rats; D011922:Rats, Mutant Strains; D012160:Retina / Q000502:physiology*; D012174:Retinitis Pigmentosa / Q000503:physiopathology*; D012684:Sensory Thresholds / Q000187:drug effects; D014822:Vitreous Body
D020934:Ciliary Neurotrophic Factor