Effects of environmental enrichment on GLUT expression in the visual cortex of amblyopic rats

Objective: To investigate the potential changes of glucose metabolism and glucose transporter protein (GLUT) in the visual cortex of formally deprived amblyopic rats, as well as the effects of enriched environments on the levels of nerve conduction and glucose metabolism in the visual cortex of amblyopic rats.

Methods: 36 rats were randomly divided into three groups: CON + SE (n = 12), MD + SE (n = 12) and MD + EE (n = 12). The right eyelids of both MD + SE and MD + EE groups were sutured. After successful modelling, the MD + EE group was maintained in an enriched environment, and the other two groups were kept in the same environment. Pattern visual evoked potentials (PVEP) was used to confirm models' effect, glucose metabolism was analyzed by Micro-PET/CT (¹⁸F-FDG), and the protein as well as mRNA expression levels of GLUT were detected by Western Blot and quantitative RT-PCR (quantitative Reverse Transcription-Polymerase Chain Reaction) analyses, site of GLUT expression by immunofluorescence (IF).

Results: After suture modelling, both the MD + EE and MD + SE groups objective visual nerve conduction function decreased, the glucose metabolism in the visual cortex was markedly lower. After the enriched environment intervention, it recovered in the MD + EE group. The expression levels of GLUT1 and GLUT3 were increased in the MD + EE group in comparison with the MD + SE group. GLUT1 was primarily expressed on astrocytes and endothelial cells, but GLUT3 was mainly expressed on neurons.

Conclusion: Enrichment of the environment exhibited a therapeutic effect on amblyopia, which could be related to the enhancement of glucose metabolism and GLUT expression in the visual cortex.