Blue Light Damage

Summary: The rodent blue light damage (BLD) model is a well-established model for retinal degeneration, oxidative stress and neuroinflammatory activity.

Model description

Blue Light Damage is a multi-faceted process affecting chromophores that absorb blue light, such as cytochrome oxidase and rhodopsin. The BLD model is a quick inducible method for causing photo-oxidative damage that is primarily localized to the outer retina, including bipolar, photoreceptor and RPE cell layers. Because cell death is apoptotic rather than necrotic, the BLD model mirrors retinal degeneration in human diseases including AMD, retinitis pigmentosa (RP), and retinal detachment. Acute BLD typically results in geographically irregular apoptosis and retinal atrophy, which is similar to atrophy seen in the terminal stage of dry AMD.

At Experimentica, we have fully implemented and validated the rat BLD model with clinically relevant reference compounds and the most comprehensive list of read-outs.

Animal speciesRats
Method of inductionBlue light
Follow-up periodTypically up to 7 days
Route of compound administrationIntravitreal, topical, systemic
Read-outs1. Flash electroretinography (fERG): functional deficits are observed both in a-wave and b-wave amplitudes in 6- and 8-hour exposure to blue light;
2. Histology: quantitative assessment of retinal thickness

Outcomes and Capabilities

Functional assessment

We use flash electroretinography (fERG) to observe functional deficits both in a-wave and b-wave amplitudes in 6 and 8 hour exposure to blue light in the rat BLD model.

Fig. 1 . Flash electroretinograms (ERG) in the Blue light damage (BLD) rat model.
Fig. 1 . Flash electroretinograms (ERG) in the Blue light damage (BLD) rat model. Retinal damage is dependent on light exposure time. ERGs were performed 5 days after light exposure.

We also use flash electroretinography (fERG) to observe functional deficits both in a-wave and b-wave amplitudes in vehicle treated eyes compared to Betaxon treated eyes.

Fig. 2. Maximum response amplitude on flash electroretinograms (ERG) in the Blue light damage (BLD) rat model following 0.5% Betaxon topical ocular treatment.
Fig. 2. Maximum response amplitude on flash electroretinograms (ERG) in the Blue light damage (BLD) rat model following 0.5% Betaxon topical ocular treatment. Retinal function is protected in Betaxon treated eyes.

Histology

Retinal histologic sections showing protection of retina in Betaxon treated eye on a rat BLD model.

Fig. 3. Retinal Histology sections of Blue light damage (BLD) rat model following 0.5% Betaxon topical ocular treatment.
Fig. 3. Retinal Histology sections of Blue light damage (BLD) rat model following 0.5% Betaxon topical ocular treatment. Retinal damage is observed on vehicle treated eyes.

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