Neuroprotective dose response in RCS rats implanted with microphotodiode arrays

Adv Exp Med Biol. 2012:723:115-20. doi: 10.1007/978-1-4614-0631-0_16.

Abstract

Purpose: Neuropreservation of retinal function and structure in RCS rats following implantation of a microphotodiode array (MPA) has been shown in previous studies(Pardue et al. 2005a; Pardue et al. 2005b). Since microphotodiodes produce electrical currents in proportion to the intensity of incident light, increased light exposure may result in greater neuroprotective effects. Our previous studies suggested that the frequency of light exposure to electroretinogram (ERG) flash stimuli might provide increased neuroprotection. Thus, in this study, we examined the dose response of subretinal electrical stimulation by exposing RCS rats implanted with MPAs to variable durations and combinations of two different lighting regimens: pulsing incandescent bulbs and xenon stimuli from an ERG Ganzfeld. While incandescent light regimens did not produce any significant differences in ERG function, we found significantly greater dark-adapted ERG b-wave amplitudes in RCS rats that received weekly versus biweekly ERGs over the course of 8 weeks of follow-up. These results suggest that subretinal electrical stimulation may be optimized to produce greater neuroprotective effects by dosing with periodic higher current.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Survival / physiology
  • Cell Survival / radiation effects
  • Dose-Response Relationship, Radiation
  • Electric Stimulation Therapy / instrumentation*
  • Electric Stimulation Therapy / methods*
  • Electrodes, Implanted*
  • Electroretinography
  • Lighting
  • Photic Stimulation / methods
  • Photoreceptor Cells, Vertebrate / cytology
  • Photoreceptor Cells, Vertebrate / physiology
  • Photoreceptor Cells, Vertebrate / radiation effects
  • Rats
  • Rats, Mutant Strains
  • Retinal Degeneration / pathology
  • Retinal Degeneration / therapy*
  • Retinitis Pigmentosa / pathology
  • Retinitis Pigmentosa / therapy*