Abstract
Purpose: :
Usher syndrome (US) is a recessively inherited disorder combining retinitis pigmentosa and a sensorineural hearing loss. The molecular mechanisms underlying the visual impairment are poorly understood and characterized. New Usher mouse models were recently generated to investigate the disease physiopathology and develop gene therapy. The purpose of this study was to analyse at a functional and a morphological level the retinal phenotypes of a mouse model of Usher Syndrome I ( SANS protein).
Methods: :
In vivo measurements were achieved on mice deficient for Ush1G gene and compared to a control group. All the subjects were 18 months years old at the time of the experiment. The functional analysis was performed with a xenon lamp electroretinogram for measuring retinal responses at different light intensities in scotopic, photopic and flicker conditions. The retinal morphology was analyzed by ocular coherence tomography (OCT) in all quadrants of the eye.
Results: :
High resolution OCT images did show any difference in the retinal thickness between US1G and control groups, assuming there is no detectable photoreceptor degeneration. In electronretinogram measurement under both scotopic, photopic and flicker light conditions, no change in amplitude or latency could be detected.
Conclusions: :
This study indicate that no photoreceptor degeneration can be detected in vivo on Usher1 mice, which will hamper the development of a therapy on the murine model. Future studies will investigate at the histological level if cellular and molecular changes can be detected in the deficient mice.
Keywords: retinal degenerations: hereditary • pathobiology