Abstract
Purpose :
Metabolic Syndrome (MetSyn) is a complex disorder of metabolism that affects different organs including the retina, triggering retinopathy. This disease presents, in addition to vascular alterations, a progressive neuronal degeneration. In this sense, α2-Macroglobulin (α2-M) has been proposed as a mediator of neurotoxicity, through their specific receptor, LRP-1. The purpose of this work was to evaluate gene and protein expression of α2-M/ LRP-1 system in retinas of mouse model of MetSyn that exhibits features of early stage (non-proliferative) of retinopathy, such as neuronal impairment and mild vascular alterations.
Methods :
C57BL/6 (WT) and Apolipoprotein E knockout (ApoE KO) mice fed with normal diet (ND) or 10% w/v fructose diet (FD) in drinking water from 2 months of age were used. After 3 months of diet, retinal extracts were obtained for Western blot, qRT-PCR and retinal cryosections for immunofluorescence analysis. Data was statistically analyzed by two-way ANOVA and Bonferroni post-hoc (p ≤ 0.05). All experimental procedures will be carried out following the standards of The Association for Research in Vision and Ophthalmology (ARVO) and the ethics committee of FCQ- UNC.
Results :
The results showed α2-M mRNA expression in mice retina and a significant increase of α2-M protein expression in retinal extracts of ApoE KO mice with both diets [WT ND vs ApoE KO FD (p< 0,0001) vs ApoE KO FD (p< 0,039)], demonstrating that their expression is increased in mice with metabolic alterations. However, LRP-1 protein expression showed no differences between the experimental groups. Immunofluorescence results showed α2-M and LRP-1 protein expression, principally in the inner nuclear layer, in Müller glial cells (glutamine synthetase), in the inner limiting membrane and in neurons (β3-tubulin), specifically in ganglion cell layer of mouse retina.
Conclusions :
These results are more than encouraging and strongly support the study of the possible neurodegenerative role of α2-M/ LRP-1 system in early stage of retinopathy induced by MetSyn.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.