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A model for the easy assessment of pressure-dependent damage to retinal ganglion cells using cyan fluorescent protein-expressing transgenic mice.

Tsuruga H, Murata H, Araie M, Aihara M - Mol. Vis. (2012)

Bottom Line: Laser-treated eyes showed a significantly higher IOP than control eyes from 1 to 7 weeks (p<0.01).The pressure insult and the RGC density showed a significant negative correlation (y=-0.070x+97.2, r=0.75, p=0.0008).Moreover, the central, middle, and peripheral areas measured from the optic disc and each of four retinal quadrant areas also showed significant negative correlations.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.

ABSTRACT

Purpose: To establish an animal model for the easy assessment of pressure-dependent damage to retinal ganglion cells (RGCs) using the B6.Cg-TgN(Thy1-CFP)23Jrs/J transgenic mouse strain (CFP mouse), which expresses cyan fluorescent protein (CFP) in RGCs, and to evaluate pressure-dependent RGC death.

Methods: In 20 CFP mice, right eyes were selected to receive laser-induced ocular hypertension eye and the contralateral eyes remained untouched to serve as controls. Intraocular pressure (IOP) was measured each week in both eyes using the microneedle method up to 8 weeks. Based on the line plot of time (x) and IOP (y) in laser-treated and control eyes, the area surrounded by both lines (∫ΔIOP(y) dx) was calculated as a surrogate value of the pressure insult. At 9 weeks, eyes were enucleated and RGCs expressing CFP were evaluated histologically in retinal whole mounts. The correlation between pressure insult and RGC density was evaluated in the whole eye, three concentric regions, and four quadrants.

Results: Laser-treated eyes showed a significantly higher IOP than control eyes from 1 to 7 weeks (p<0.01). The pressure insult and the RGC density showed a significant negative correlation (y=-0.070x+97.2, r=0.75, p=0.0008). Moreover, the central, middle, and peripheral areas measured from the optic disc and each of four retinal quadrant areas also showed significant negative correlations. Our data demonstrate that each retinal area was almost evenly damaged by IOP elevation.

Conclusions: Laser photocoagulation causes a chronic elevation of IOP in CFP mice. The use of CFP mice enabled us to easily evaluate pressure-dependent RGC damage. This glaucomatous CFP mouse model may contribute to the molecular analysis of neurodegeneration and the development of neuroprotective drugs for glaucoma with a great increase in experimental efficiency.

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Related in: MedlinePlus

Definition of pressure-insult for a surrogate value. Based on the line plot of time (x) and IOP (y) in laser-treated and control eyes, the area surrounded by both lines (∫ΔIOP(y) dx) was calculated as a surrogate value of the pressure-insult.
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f2: Definition of pressure-insult for a surrogate value. Based on the line plot of time (x) and IOP (y) in laser-treated and control eyes, the area surrounded by both lines (∫ΔIOP(y) dx) was calculated as a surrogate value of the pressure-insult.

Mentions: The IOPs in the treated and the contralateral control eyes and the duration of IOP elevation in the treated eye were calculated. For each animal, a graph of IOP over time was constructed for the treated and control eyes. The area under the curve of the treated and control eyes was calculated in units of mmHg×day. The area under the control eye curve was subtracted from the area under the treated eye curve to assess the magnitude of IOP elevation. Total area for the period during which the IOP in the treated eye was higher than in the control eye defined a surrogate value of the pressure insult in the treated eye for elevated IOP (Figure 2).


A model for the easy assessment of pressure-dependent damage to retinal ganglion cells using cyan fluorescent protein-expressing transgenic mice.

Tsuruga H, Murata H, Araie M, Aihara M - Mol. Vis. (2012)

Definition of pressure-insult for a surrogate value. Based on the line plot of time (x) and IOP (y) in laser-treated and control eyes, the area surrounded by both lines (∫ΔIOP(y) dx) was calculated as a surrogate value of the pressure-insult.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3472928&req=5

f2: Definition of pressure-insult for a surrogate value. Based on the line plot of time (x) and IOP (y) in laser-treated and control eyes, the area surrounded by both lines (∫ΔIOP(y) dx) was calculated as a surrogate value of the pressure-insult.
Mentions: The IOPs in the treated and the contralateral control eyes and the duration of IOP elevation in the treated eye were calculated. For each animal, a graph of IOP over time was constructed for the treated and control eyes. The area under the curve of the treated and control eyes was calculated in units of mmHg×day. The area under the control eye curve was subtracted from the area under the treated eye curve to assess the magnitude of IOP elevation. Total area for the period during which the IOP in the treated eye was higher than in the control eye defined a surrogate value of the pressure insult in the treated eye for elevated IOP (Figure 2).

Bottom Line: Laser-treated eyes showed a significantly higher IOP than control eyes from 1 to 7 weeks (p<0.01).The pressure insult and the RGC density showed a significant negative correlation (y=-0.070x+97.2, r=0.75, p=0.0008).Moreover, the central, middle, and peripheral areas measured from the optic disc and each of four retinal quadrant areas also showed significant negative correlations.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan.

ABSTRACT

Purpose: To establish an animal model for the easy assessment of pressure-dependent damage to retinal ganglion cells (RGCs) using the B6.Cg-TgN(Thy1-CFP)23Jrs/J transgenic mouse strain (CFP mouse), which expresses cyan fluorescent protein (CFP) in RGCs, and to evaluate pressure-dependent RGC death.

Methods: In 20 CFP mice, right eyes were selected to receive laser-induced ocular hypertension eye and the contralateral eyes remained untouched to serve as controls. Intraocular pressure (IOP) was measured each week in both eyes using the microneedle method up to 8 weeks. Based on the line plot of time (x) and IOP (y) in laser-treated and control eyes, the area surrounded by both lines (∫ΔIOP(y) dx) was calculated as a surrogate value of the pressure insult. At 9 weeks, eyes were enucleated and RGCs expressing CFP were evaluated histologically in retinal whole mounts. The correlation between pressure insult and RGC density was evaluated in the whole eye, three concentric regions, and four quadrants.

Results: Laser-treated eyes showed a significantly higher IOP than control eyes from 1 to 7 weeks (p<0.01). The pressure insult and the RGC density showed a significant negative correlation (y=-0.070x+97.2, r=0.75, p=0.0008). Moreover, the central, middle, and peripheral areas measured from the optic disc and each of four retinal quadrant areas also showed significant negative correlations. Our data demonstrate that each retinal area was almost evenly damaged by IOP elevation.

Conclusions: Laser photocoagulation causes a chronic elevation of IOP in CFP mice. The use of CFP mice enabled us to easily evaluate pressure-dependent RGC damage. This glaucomatous CFP mouse model may contribute to the molecular analysis of neurodegeneration and the development of neuroprotective drugs for glaucoma with a great increase in experimental efficiency.

Show MeSH
Related in: MedlinePlus