Ethanol Consumption Correlates with Retinal Degeneration and Vision Loss in the P23H Rat

Abstract

 

Purpose:

 

Ethanol consumption induces morphological and functional alterations in the rat retina. The objective of this study is to assess the neurodegenerative potential of ethanol in the P23H rat model of retinitis pigmentosa.

 

Methods:

 

Homozygous P23H (line 3) rats were initially divided in four groups (n = 8) receiving ethanol throughout the drinking water at 0, 0.25, 0.5 and 0.75 g/kg/day from P20 to P180. In these rats, visual function has been evaluated by electroretinographic (ERG) recording at P60, P120 and P180. Degeneration of retinal structure has been assessed by immunohistochemistry at P180.

 

Results:

 

ERG recordings showed that age-related vision loss in P23H rats positively correlated with the dosage of ethanol administered. The maximum scotopic b-wave responses were significantly smaller in animals treated with ethanol at 0.75 g/kg/day than in control rats at P60, P120 and P180. Ethanol-induced visual deterioration positively correlated with photoreceptor loss and degeneration of retinal cytoarchitecture. Vertical sections of the retinas showed a significant reduction in the number of photoreceptor layers in 0.75 g/kg/day ethanol-treated rats when compared to untreated animals.

 

Conclusions:

 

Our data demonstrate that moderate doses of ethanol accelerate retinal degeneration and the loss of retinal function in the P23H rat.

 

Keywords: retinal degenerations: cell biology • electroretinography: non-clinical • retinitis