Limits...
Spectral-domain optical coherence tomography of the rodent eye: highlighting layers of the outer retina using signal averaging and comparison with histology.

Berger A, Cavallero S, Dominguez E, Barbe P, Simonutti M, Sahel JA, Sennlaub F, Raoul W, Paques M, Bemelmans AP - PLoS ONE (2014)

Bottom Line: We show that the thickness of the various layers can be measured as accurately in vivo on SD-OCT images, than post-mortem by a morphometric analysis of histological sections.We applied SD-OCT to different models and demonstrated that it allows analysis of focal or diffuse retinal pathological processes such as mutation-dependent damages or light-driven modification of photoreceptors.In conclusion, we clearly demonstrated that SD-OCT represents a valuable tool for imaging the rodent retina that is at least as accurate as histology, non-invasive and allows longitudinal follow-up of the same animal.

View Article: PubMed Central - PubMed

Affiliation: Inserm, U 968, Paris, France; UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France.

ABSTRACT
Spectral-Domain Optical Coherence Tomography (SD-OCT) is a widely used method to observe retinal layers and follow pathological events in human. Recently, this technique has been adapted for animal imaging. This non-invasive technology brings a cross-sectional visualization of the retina, which permits to observe precisely each layer. There is a clear expansion of the use of this imaging modality in rodents, thus, a precise characterization of the different outer retinal layers observed by SD-OCT is now necessary to make the most of this technology. The identification of the inner strata until the outer nuclear layer has already been clearly established, while the attribution of the layers observed by SD-OCT to the structures corresponding to photoreceptors segments and retinal pigment epithelium is much more questionable. To progress in the understanding of experimental SD-OCT imaging, we developed a method for averaging SD-OCT data to generate a mean image allowing to better delineate layers in the retina of pigmented and albino strains of mice and rats. It allowed us to locate precisely the interface between photoreceptors and retinal pigment epithelium and to identify unambiguously four layers corresponding to the inner and outer parts of photoreceptors segments. We show that the thickness of the various layers can be measured as accurately in vivo on SD-OCT images, than post-mortem by a morphometric analysis of histological sections. We applied SD-OCT to different models and demonstrated that it allows analysis of focal or diffuse retinal pathological processes such as mutation-dependent damages or light-driven modification of photoreceptors. Moreover, we report a new method of combined use of SD-OCT and integration to quantify laser-induced choroidal neovascularization. In conclusion, we clearly demonstrated that SD-OCT represents a valuable tool for imaging the rodent retina that is at least as accurate as histology, non-invasive and allows longitudinal follow-up of the same animal.

Show MeSH

Related in: MedlinePlus

Characterization of a retinal degeneration mouse model by SD-OCT.SD-OCT images of control mice retina (A) and rho−/− mice retina (B) from post-natal day 21 (P21) to 180 (P180). Magnification (X2.4) of P21 and P180 control mice outer retina (C) and rho−/− mice (D). (E) Measures of INL thickness obtained from SD-OCT data in control and rho−/− mice (P21: p = 0.0123; P180: p = 0.7125). (F) Measures of ONL thickness obtained from SD-OCT data in control and rho−/− mice (P21 and P180: p<0.0001). (G) Measures of ONL thickness obtained from morphometric measurements on cryostat sections in control and rho−/− mice (P15 and P180: p = 0.0022). Statistical significance of the difference between groups was analyzed at the initial time-point (P15 or P21) and the latest time-point (P180) studied by Student's T-test for E and F (n = 23 per group) and by Mann Whitney test for G (n = 6 per group). IPL: inner plexiform layer, INL: inner nuclear layer, ONL: outer nuclear layer, OLM: outer limiting membrane, RPE: retinal pigmented epithelium. SD: Standard Deviation. Scale bars: 50 µm.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4008571&req=5

pone-0096494-g003: Characterization of a retinal degeneration mouse model by SD-OCT.SD-OCT images of control mice retina (A) and rho−/− mice retina (B) from post-natal day 21 (P21) to 180 (P180). Magnification (X2.4) of P21 and P180 control mice outer retina (C) and rho−/− mice (D). (E) Measures of INL thickness obtained from SD-OCT data in control and rho−/− mice (P21: p = 0.0123; P180: p = 0.7125). (F) Measures of ONL thickness obtained from SD-OCT data in control and rho−/− mice (P21 and P180: p<0.0001). (G) Measures of ONL thickness obtained from morphometric measurements on cryostat sections in control and rho−/− mice (P15 and P180: p = 0.0022). Statistical significance of the difference between groups was analyzed at the initial time-point (P15 or P21) and the latest time-point (P180) studied by Student's T-test for E and F (n = 23 per group) and by Mann Whitney test for G (n = 6 per group). IPL: inner plexiform layer, INL: inner nuclear layer, ONL: outer nuclear layer, OLM: outer limiting membrane, RPE: retinal pigmented epithelium. SD: Standard Deviation. Scale bars: 50 µm.

Mentions: After having established reliability of SD-OCT for imaging of healthy retina, we wanted to show the usefulness of this technology to characterize the occurrence of physiological or pathological events in the rodent retina. Firstly, we studied degeneration of PR in a retinitis pigmentosa mouse model. Rho−/− mice are a retinal degeneration model [15] that presents a loss of almost all photoreceptors at post-natal day 90 (P90). We followed this degeneration by SD-OCT from P21 to P180, and compared quantification of INL and ONL thickness to those of C57BL/6JRj control mice (Fig. 3A–D). While INL thickness variation was equivalent between rho−/− and control mice (Fig. 3E), ONL thickness dramatically decreased until complete vanishing at P180 in rho−/− mice (Fig. 3F). As expected, the same observation was done by histology after DAPI labeling and automated measurements (Fig. 3G). Nevertheless, values' dispersion was far more important with histological measures than with SD-OCT imaging. This highlights that SD-OCT is a valuable tool for in vivo monitoring of retinal degeneration in the same animal.


Spectral-domain optical coherence tomography of the rodent eye: highlighting layers of the outer retina using signal averaging and comparison with histology.

Berger A, Cavallero S, Dominguez E, Barbe P, Simonutti M, Sahel JA, Sennlaub F, Raoul W, Paques M, Bemelmans AP - PLoS ONE (2014)

Characterization of a retinal degeneration mouse model by SD-OCT.SD-OCT images of control mice retina (A) and rho−/− mice retina (B) from post-natal day 21 (P21) to 180 (P180). Magnification (X2.4) of P21 and P180 control mice outer retina (C) and rho−/− mice (D). (E) Measures of INL thickness obtained from SD-OCT data in control and rho−/− mice (P21: p = 0.0123; P180: p = 0.7125). (F) Measures of ONL thickness obtained from SD-OCT data in control and rho−/− mice (P21 and P180: p<0.0001). (G) Measures of ONL thickness obtained from morphometric measurements on cryostat sections in control and rho−/− mice (P15 and P180: p = 0.0022). Statistical significance of the difference between groups was analyzed at the initial time-point (P15 or P21) and the latest time-point (P180) studied by Student's T-test for E and F (n = 23 per group) and by Mann Whitney test for G (n = 6 per group). IPL: inner plexiform layer, INL: inner nuclear layer, ONL: outer nuclear layer, OLM: outer limiting membrane, RPE: retinal pigmented epithelium. SD: Standard Deviation. Scale bars: 50 µm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4008571&req=5

pone-0096494-g003: Characterization of a retinal degeneration mouse model by SD-OCT.SD-OCT images of control mice retina (A) and rho−/− mice retina (B) from post-natal day 21 (P21) to 180 (P180). Magnification (X2.4) of P21 and P180 control mice outer retina (C) and rho−/− mice (D). (E) Measures of INL thickness obtained from SD-OCT data in control and rho−/− mice (P21: p = 0.0123; P180: p = 0.7125). (F) Measures of ONL thickness obtained from SD-OCT data in control and rho−/− mice (P21 and P180: p<0.0001). (G) Measures of ONL thickness obtained from morphometric measurements on cryostat sections in control and rho−/− mice (P15 and P180: p = 0.0022). Statistical significance of the difference between groups was analyzed at the initial time-point (P15 or P21) and the latest time-point (P180) studied by Student's T-test for E and F (n = 23 per group) and by Mann Whitney test for G (n = 6 per group). IPL: inner plexiform layer, INL: inner nuclear layer, ONL: outer nuclear layer, OLM: outer limiting membrane, RPE: retinal pigmented epithelium. SD: Standard Deviation. Scale bars: 50 µm.
Mentions: After having established reliability of SD-OCT for imaging of healthy retina, we wanted to show the usefulness of this technology to characterize the occurrence of physiological or pathological events in the rodent retina. Firstly, we studied degeneration of PR in a retinitis pigmentosa mouse model. Rho−/− mice are a retinal degeneration model [15] that presents a loss of almost all photoreceptors at post-natal day 90 (P90). We followed this degeneration by SD-OCT from P21 to P180, and compared quantification of INL and ONL thickness to those of C57BL/6JRj control mice (Fig. 3A–D). While INL thickness variation was equivalent between rho−/− and control mice (Fig. 3E), ONL thickness dramatically decreased until complete vanishing at P180 in rho−/− mice (Fig. 3F). As expected, the same observation was done by histology after DAPI labeling and automated measurements (Fig. 3G). Nevertheless, values' dispersion was far more important with histological measures than with SD-OCT imaging. This highlights that SD-OCT is a valuable tool for in vivo monitoring of retinal degeneration in the same animal.

Bottom Line: We show that the thickness of the various layers can be measured as accurately in vivo on SD-OCT images, than post-mortem by a morphometric analysis of histological sections.We applied SD-OCT to different models and demonstrated that it allows analysis of focal or diffuse retinal pathological processes such as mutation-dependent damages or light-driven modification of photoreceptors.In conclusion, we clearly demonstrated that SD-OCT represents a valuable tool for imaging the rodent retina that is at least as accurate as histology, non-invasive and allows longitudinal follow-up of the same animal.

View Article: PubMed Central - PubMed

Affiliation: Inserm, U 968, Paris, France; UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, France.

ABSTRACT
Spectral-Domain Optical Coherence Tomography (SD-OCT) is a widely used method to observe retinal layers and follow pathological events in human. Recently, this technique has been adapted for animal imaging. This non-invasive technology brings a cross-sectional visualization of the retina, which permits to observe precisely each layer. There is a clear expansion of the use of this imaging modality in rodents, thus, a precise characterization of the different outer retinal layers observed by SD-OCT is now necessary to make the most of this technology. The identification of the inner strata until the outer nuclear layer has already been clearly established, while the attribution of the layers observed by SD-OCT to the structures corresponding to photoreceptors segments and retinal pigment epithelium is much more questionable. To progress in the understanding of experimental SD-OCT imaging, we developed a method for averaging SD-OCT data to generate a mean image allowing to better delineate layers in the retina of pigmented and albino strains of mice and rats. It allowed us to locate precisely the interface between photoreceptors and retinal pigment epithelium and to identify unambiguously four layers corresponding to the inner and outer parts of photoreceptors segments. We show that the thickness of the various layers can be measured as accurately in vivo on SD-OCT images, than post-mortem by a morphometric analysis of histological sections. We applied SD-OCT to different models and demonstrated that it allows analysis of focal or diffuse retinal pathological processes such as mutation-dependent damages or light-driven modification of photoreceptors. Moreover, we report a new method of combined use of SD-OCT and integration to quantify laser-induced choroidal neovascularization. In conclusion, we clearly demonstrated that SD-OCT represents a valuable tool for imaging the rodent retina that is at least as accurate as histology, non-invasive and allows longitudinal follow-up of the same animal.

Show MeSH
Related in: MedlinePlus