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Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration.

Cuenca N, Fernández-Sánchez L, Sauvé Y, Segura FJ, Martínez-Navarrete G, Tamarit JM, Fuentes-Broto L, Sanchez-Cano A, Pinilla I - Front Neuroanat (2014)

Bottom Line: Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections.Statistically significant differences were found in all evaluated thicknesses.Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Genetics and Microbiology, University of Alicante Alicante, Spain.

ABSTRACT

Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.

Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry.

Results: Between P30 and P180, visual acuity decreased from 0.500 to 0.182 cycles per degree (cyc/deg) and contrast sensitivity decreased from 54.56 to 2.98 for a spatial frequency of 0.089 cyc/deg. Only cone-driven b-wave responses reached developmental maturity. Flicker fusions were also comparable at P29 (42 Hz). Double flash-isolated rod-driven responses were already affected at P29. Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections. Statistically significant differences were found in all evaluated thicknesses. Autofluorescence was seen in P23H rats as sparse dots. Immunocytochemistry showed a progressive decrease in the outer nuclear layer (ONL), and morphological changes. Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.

Conclusions: In pigmented P23H rats, a progressive deterioration occurs in both retinal function and anatomy. Anatomical changes can be effectively evaluated using SD-OCT and immunocytochemistry, with a good correlation between their values, thus making SD-OCT an important tool for research in retinal degeneration.

No MeSH data available.


Related in: MedlinePlus

Cone bipolar cell modifications during retinal degeneration of P23H pigmented L1 rats. Retinal sections stained with antibodies against recoverin in order to visualize the degenerative process of cone bipolar cells in P23H (B–F) rat retina, compared to the control (A). Along the degenerative process, cone bipolar cells show changes from P60 onwards, with profuse axonal loss at the IPL level. INL: inner nuclear layer; IPL: inner plexiform layer; S1: Stratum 1; S2: Stratum 2; S3: Stratum 3; S4: Stratum 4; S5: Stratum 5; GCL: ganglion cell layer. Scale bar: 40 µm.
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Figure 12: Cone bipolar cell modifications during retinal degeneration of P23H pigmented L1 rats. Retinal sections stained with antibodies against recoverin in order to visualize the degenerative process of cone bipolar cells in P23H (B–F) rat retina, compared to the control (A). Along the degenerative process, cone bipolar cells show changes from P60 onwards, with profuse axonal loss at the IPL level. INL: inner nuclear layer; IPL: inner plexiform layer; S1: Stratum 1; S2: Stratum 2; S3: Stratum 3; S4: Stratum 4; S5: Stratum 5; GCL: ganglion cell layer. Scale bar: 40 µm.

Mentions: In addition to photoreceptors, recoverin antibodies also label two types of cone bipolar cells in the rat retina (McGinnis et al., 1999; Cuenca et al., 2004). At P20, these two types of cone bipolar cells remained unchanged as compared to the control retinas. Type 8 ON-cone bipolar cells had a diffuse plexus of axons, terminating in the inner IPL, in strata S4-S5. Their cell body, located near the OPL, was weakly immunoreactive to recoverin (Figure 12A arrows). The second, Type 2, was an OFF-cone bipolar cell (Figure 12A, arrowheads), with strong immunoreactivity in the cell body, located near the middle of the INL, and an axon making a dense continuous plexus in strata S1 and S2 of the IPL. By P40 and P60, the general morphology of these cone bipolar cells was not drastically modified, and the only apparent change was a decrease in cell body density (Figures 12B,C).


Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration.

Cuenca N, Fernández-Sánchez L, Sauvé Y, Segura FJ, Martínez-Navarrete G, Tamarit JM, Fuentes-Broto L, Sanchez-Cano A, Pinilla I - Front Neuroanat (2014)

Cone bipolar cell modifications during retinal degeneration of P23H pigmented L1 rats. Retinal sections stained with antibodies against recoverin in order to visualize the degenerative process of cone bipolar cells in P23H (B–F) rat retina, compared to the control (A). Along the degenerative process, cone bipolar cells show changes from P60 onwards, with profuse axonal loss at the IPL level. INL: inner nuclear layer; IPL: inner plexiform layer; S1: Stratum 1; S2: Stratum 2; S3: Stratum 3; S4: Stratum 4; S5: Stratum 5; GCL: ganglion cell layer. Scale bar: 40 µm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4273614&req=5

Figure 12: Cone bipolar cell modifications during retinal degeneration of P23H pigmented L1 rats. Retinal sections stained with antibodies against recoverin in order to visualize the degenerative process of cone bipolar cells in P23H (B–F) rat retina, compared to the control (A). Along the degenerative process, cone bipolar cells show changes from P60 onwards, with profuse axonal loss at the IPL level. INL: inner nuclear layer; IPL: inner plexiform layer; S1: Stratum 1; S2: Stratum 2; S3: Stratum 3; S4: Stratum 4; S5: Stratum 5; GCL: ganglion cell layer. Scale bar: 40 µm.
Mentions: In addition to photoreceptors, recoverin antibodies also label two types of cone bipolar cells in the rat retina (McGinnis et al., 1999; Cuenca et al., 2004). At P20, these two types of cone bipolar cells remained unchanged as compared to the control retinas. Type 8 ON-cone bipolar cells had a diffuse plexus of axons, terminating in the inner IPL, in strata S4-S5. Their cell body, located near the OPL, was weakly immunoreactive to recoverin (Figure 12A arrows). The second, Type 2, was an OFF-cone bipolar cell (Figure 12A, arrowheads), with strong immunoreactivity in the cell body, located near the middle of the INL, and an axon making a dense continuous plexus in strata S1 and S2 of the IPL. By P40 and P60, the general morphology of these cone bipolar cells was not drastically modified, and the only apparent change was a decrease in cell body density (Figures 12B,C).

Bottom Line: Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections.Statistically significant differences were found in all evaluated thicknesses.Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Genetics and Microbiology, University of Alicante Alicante, Spain.

ABSTRACT

Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.

Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry.

Results: Between P30 and P180, visual acuity decreased from 0.500 to 0.182 cycles per degree (cyc/deg) and contrast sensitivity decreased from 54.56 to 2.98 for a spatial frequency of 0.089 cyc/deg. Only cone-driven b-wave responses reached developmental maturity. Flicker fusions were also comparable at P29 (42 Hz). Double flash-isolated rod-driven responses were already affected at P29. Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections. Statistically significant differences were found in all evaluated thicknesses. Autofluorescence was seen in P23H rats as sparse dots. Immunocytochemistry showed a progressive decrease in the outer nuclear layer (ONL), and morphological changes. Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.

Conclusions: In pigmented P23H rats, a progressive deterioration occurs in both retinal function and anatomy. Anatomical changes can be effectively evaluated using SD-OCT and immunocytochemistry, with a good correlation between their values, thus making SD-OCT an important tool for research in retinal degeneration.

No MeSH data available.


Related in: MedlinePlus