Investigating degeneration of the retina in young and aged tau P301L mice

Abstract Aims Tau is a microtubule-binding protein facilitating the stability of the cytoskeleton. It is important for neurons as several neurodegenerative diseases involve hyperphosphorylation and aggregation of tau. It is known that mutated tau P301L results in aggregation of tau proteins, leading to neuronal loss in the brain. The aim of this study was to investigate the effect of tau mutation on the retina using a transgenic tau P301L mouse model. Main methods Morphometric analysis was utilized to quantify the neurodegenerative changes, including the thickness of the inner nuclear layer (INL), and the density and size of retinal ganglion cells (RGCs). Sections of retina tissue stained by hematoxylin and eosin (H&E) and immunohistochemistry were analyzed. Comparisons were made between the tau P301L mice and control mice, as well as between different age groups. Key findings A significant decrease in the thickness of the INL in tau P301L mice was found when compared with that of control mice. The effect was more pronounced in the peripheral area, and the effect increased with age. Regarding density of RGCs, tau P301L mice showed a similar age-related decline as in control mice. Furthermore, the RGCs from tau P301L mice increased in size with age, and the RGCs from control mice decreased in size with age. Significance Tau may be an age-independent factor of accelerated neurodegeneration, with effects differing by types of neurons and regions of the retina.