[Alterations of retinal tissue induced by amyloid ß(1- 42) subretinal injection in mice].

ABSTRACT

OBJECTIVE: To investigate the alterations of retinal tissue induced by OAß(1-42) subretinal injection in normal C57BL/6N mice. METHODS: Experimental study. One hundred and twenty C57BL/6N mice aged 8 weeks participated in this study. Among them, 60 eyes received subretinal injection of OAß(1-42); another 60 received double distilled water as control. The concentration of OAß(1-42) was 0.312 5 mmol/L. We took fundus photograph and autofluorescence, electroretinogram(ERG), haematoxylineosin staining of retinal paraffin sections, ß-galactosidase staining of neural retinal flatmounts, immunofluorescence of senescence marker P16INK4a of RPE/choroidal flatmounts, Western blot and RT-PCR of senescence relative cytokines IL-6, TGF-ß1 before and after the injection. The data were analyzed by independent sample t-test. RESULTS: Comparing with controls, 1 week post injection, the experimental group eyes had atrophied area with high autofluorescence site, and showed evident decrease in amplitudes of a wave (39.94±7.75)µV comparing with the controls (225.27±28.94)µV(t=12.45, P<0.001) in scotopia ERG, so did the amplitude of b wave (185.55±4.62)µV comparing with the controls (873.78±43.80)µV(t=27.06, P<0.001), retinal structures appeared significant loss of retinal thickness (t=75.13, P<0.001) along with hypo- or hyperpigmentation; the experimental eyes had high frequency of blue-green deposits in retinal ß-gal staining; the green fluorescence sites of RPE/choroidal flatmounts were clear and bright, indicating higher expression of P16INK4a in the nucleus; these results were the same till 8 weeks post operation. Western blot and RT-PCR vertified conspicuous increases in expression of TGF-ß1, IL-6 in retinas of experimental eyes compared with the control ones 1 week post injection. CONCLUSIONS: OAß(1-42) subretinal injection could induce visual function deficiency and retinal tissue senescence. All the manifestations were AMD-like retinopathy, which implied that Aß(1-42) might be an essential clue in human AMD pathology.