Visual Function and Survival of Injured Retinal Ganglion Cells in Aged Rbfox1 Knockout Animals

Area of Science:

• Neuroscience
• Ophthalmology
• Genetics

Background:

• Rbfox1 is a crucial RNA binding protein for neuronal development and function.
• Rbfox1 is implicated in neurodevelopmental, neurological, and neurodegenerative diseases.
• Rbfox1 is expressed in retinal ganglion cells (RGCs) and amacrine cells (ACs) in the mammalian retina.

Purpose of the Study:

• To investigate the impact of advanced age and Rbfox1 deficiency on visual function.
• To assess retinal morphology and RGC survival following injury in aged Rbfox1 knockout (KO) mice.
• To determine Rbfox1's role in age-related changes in RGCs.

Main Methods:

• Utilized a visual cliff test to evaluate depth perception in 22-month-old Rbfox1 KO and control mice.
• Examined retinal gross morphology.
• Performed optic nerve crush (ONC) to induce axonal injury and quantified RGC survival in Rbfox1 KO and control groups.

Main Results:

• Aged Rbfox1 KO mice exhibited significant depth perception deficiencies.
• Retinal morphology appeared normal in aged Rbfox1 KO mice.
• Rbfox1 deficiency did not alter RGC survival rates after ONC injury; RGC loss was approximately 50% in both KO and control groups.
• Contrary to expectations, RGC density in 22-month-old mice was similar to that of 4-month-old mice, suggesting preserved RGCs in aging.

Conclusions:

• Rbfox1 plays a critical role in maintaining visual function, specifically depth perception, in aged mice.
• Rbfox1 is not essential for the survival of RGCs following axonal injury.
• The study challenges the notion of significant age-related RGC loss, finding preserved RGC numbers in aged mice compared to young counterparts.