Purpose:
To determine the effect of intraocularly administered photoactive quantum dots in a rodent model of progressive photoreceptor degeneration.
Methods:
The Royal College of Surgeons (RCS) rat model of progressive photoreceptor degeneration was used for this study. Fourteen eyes of seven animals were divided into three groups: 4 eyes in the control group, 4 eyes in the sham surgery group, and 6 eyes in the active implant group. The active implant group received quantum dots composed of a cadmium/selenium core (Cd/Se) covered with a thin outer layer of zinc sulfide and conjugated with biotin , which were injected into the vitreous cavity. Similarly, the sham surgery group received an intravitreal injection of balanced saline solution, and the control group underwent no surgical procedure. All procedures were done at week six of life and weekly electroretinograms recorded for the following six weeks. The amplitude of the b-waveform from the dark-adapted maximal flash stimulus was recorded and compared between groups.
Results:
Both the control and sham surgery groups demonstrated a progressive decline in the amplitude of the ERG b-wave over the six weeks post-procedure. In contrast, the eyes receiving intravitreal photoactive quantum dots demonstrated an increase in the b-wave amplitude at weeks one through four, and then subsequently declined. Repeated measures ANOVA analysis did not demonstrate a statistically significant difference between the three groups at any time point.
Conclusions:
Although not statistically significant in these small sample size groups, the trend for the ERG b-wave amplitude to increase transiently following intravitreal injection of photoactive quantum dots in the RCS rat model suggests a potential therapeutic role for this technology.
Keywords: retina • retinal connections, networks, circuitry • retinal degenerations: hereditary