Changes of amyloid β-protein level and astrocytes in the retina of APP/PS1 double transgenic mouse models

Objective To compare the expressions of amyloid precursor protein (APP) and amyloid β-protein (Aβ),and astrocyte patterns in the retina between mouse models of Alzheimer's disease (AD) and wild type mice to explore the reasons of disordered vision.Methods Retina were removed from AD mouse models and wild-type controls of three or twelve months old;immunohistochemical staining was performed to observe the expressions of APP and Aβ in the retina;immunofluorescent staining combined with retinal stretched preparation was performed to observe the morphological and density changes of astrocytes in the retina by detecting the glial fibrillary acidic protein level.Results APP positive cells were observed in the retina of both APP/PS1 double transgenic mice and wild-type littermates,while a significant increase of APP expression was seen in the APP/PSI double transgenic mice as compared with that of wild-type controls (t=3.232,P=0.018; t=5.797,P=0.001).Aβ deposition was hardly observed in the retina of wild-type mice; however,its depositions were significantly increased in the retina of AD models with an age-dependant manner (t=6.486,P=0.001).Meanwhile,a significant increase of numbers of astrocytes with shorter and numerous processes ([602.60 ±36.35]cell/mm2 vs.[309.52±41.55] cell/mm2) were seen in the retina of AD mouse models as compared with that of wild type ones (t=5.309,P=0.006).Conclusion Aβ deposition is increased with age in the retina of AD model mice,which is accompanied with reactive astrogliosis,which indicates that Aβ deposition is closely related to the neurodegeneration of retina in the APP/PS 1 double transgenic AD models. Key words: Alzheimer's disease;  Retina;  Amyloid β protein;  Astrocyte