Fig 1.
CeNPs protected rod and cone cell functions in P23H-1 rats after a single intravitreal injection (172 ng per eye) when evaluated 24 days post injection (dpi).
The average increases for scotopic a-wave amplitudes was 180%, and 133% for photopic b-wave amplitudes across the intensities that showed statistically significant changes compared to saline-injected animals. *P<0.05, #P<0.01. N = 8–10 eyes from 4–5 animals per treatment group.
Fig 2.
CeNPs protected rod cell function only in P23H-1 rats after a single intravitreal injection (344 ng per eye) when evaluated at 34 dpi.
The average increase of scotopic a-wave amplitudes was 186% across the intensities that showed statistically significant changes compared to saline-injected animals. There was no change in the photopic b-wave amplitudes in the intensities tested, nor were there changes in the flicker ERG. *P<0.05, #P<0.01. N = 6–8 eyes from 3–4 animals per treatment group.
Table 1.
Effects of CeNPs on Rod and Cone Cell Functions of P23H-1 Rat after a Single Intravitreal Injection at Different Ages and Durations.
Fig 3.
Morphometric analysis of ONL thickness in CeNPs- and saline- treated P23H-1 rats.
One μl of 1 mM CeNPs (172 ng) or saline was delivered to each eye of the animals at P23 and eyes were harvested at 28 dpi; three eyes from 3 individuals were examined per treatment group. (A-D) Representative photomicrographs of H&E stained retinal sections from wildtype, Sprague Dawley (SD) or P23H-1 animals uninjected or treated with either saline or CeNPs. Similar regions were shown: 1 mm from the ONH in the inferior region. (E) shows quantification of the ONL thickness measurements. The overall ONL thickness was higher in CeNPs-treated than in saline-treated animals although the increases were not statistically significant across many of the regions. INL = inner nuclear layer, ONL = outer nuclear layer, I/OS = rod inner/outer segment, ONH = optic nerve head. *P<0.05.
Fig 4.
Rates of ONL thickness reduction in two photoreceptor degeneration rodent models: P23H-1 rat and tubby mouse.
Data were adapted from [23] and [28] for P23H-1 rat and tubby mouse, respectively. The decline is most rapid between P12 and P20 for both models. In this direct comparison, P23H-1 rat has a more aggressive rod cell degeneration rate between P12 and P30 than the tubby mouse.
Fig 5.
A single application of CeNPs at P15 reduced the number of apoptotic death of photoreceptor cells for at least 21 days.
(A-B) Representative photomicrographs of retinal sections from 3 dpi group with examples of TUNEL+ profiles (green). Nuclei in the ONL and INL are labeled blue. Rod outer segments are labeled red with Rhodopsin, 1D4, antibody. CeNPs-treated animals have significantly fewer TUNEL+ profiles in the ONL compared to saline-treated ones. (C) Quantification of TUNEL+ profiles in the ONL from 3, 7, 14, and 21 dpi groups. The reductions from 3 and 7 dpi groups of CeNPs injected animals were highly significant. Statistical summaries from these box plots are detailed in Table 2. Abbreviations: dpi = days post injection, S = Saline, C = CeNPs, *p<0.05.
Table 2.
Statistical Summaries of TUNEL+ profiles in the ONL of Retinal Sections from CeNPs and Saline Treated P23H-1 Rats.
Fig 6.
Quantification of lipid peroxidation in retinal samples of P23H-1 rats.
(A) Retinas of 28-day old P23H-1 rats had elevated levels of 8-isoprostanes compared to age-matched wildtype, SD controls. N = 4, #P<0.01. (B) A single CeNPs application at P15 reduced the level of 8-isoprostanes 14 days later in the retinas of P23H-1 rats. N = 5–6, *P<0.05. Abbreviations: SD = Sprague Dawley, Sal = Saline, CNP = CeNPs.