Influences of levodopa and cytidine diphosphate choline on the expression of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid GluR2 in visual cortex of monocular deprivation rats / 中华实验眼科杂志

ABSTRACT

Background Research demonstrated that alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid GluR2 (AMPA-GluR2) is associated with amblyopia.It has been shown that levodopa and cytidine diphosphate choline can improve visual function of amblyopic children,but the mechanism is unclear.Objective This study was to explore the possible effects of levodopa and cytidine diphosphate choline on amblyopia.Methods Monocular deprivation (MD) animal models were created in 60 2-week-old SD rats by monolateral eyelid suturing and observed for 31 days and reared in natural light together with 15 other matched normal healthy SD rats.The models were randomly divided into the MD group,levodopa group,cytidine diphosphate choline group and normal saline control group,with 15 rats for each group.40 mg/kg of levodopa,80 mg/kg of cytidine diphosphate choline,I ml normal saline were given to the rats,respectively,for 28 consecutive days.Expressions of the AMPA-CluR2 protein and AMPA-CluR2 mRNA in the rat visual cortex were detected by immunohistochemistry,Western blot and real-time fluorescence quantitative PCR.Use of the animals followed the Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission.Results The expression values of the AMPA-GluR2 protein (AMPA-GluR2/β-actin) and AMPA-GluR2 mRNA (2-△△Ct) were significantly lower in the MD group than those of the normal control group (protein0.32 ± 0.02 vs.0.64 ± 0.05,t =13.287,P＜0.05 ;mRNA0.30±0.01 vs.0.84±0.03,t=38.184,P＜0.05).Those in the levodopa group were significantly increased in comparison with the normal saline solution group (protein0.59 ±0.04 vs.0.33 ±0.03,t =11.628,P＜0.05 ; mRNA0.71±0.06 vs.0.33 ±0.02,t =13.435,P＜0.05).The expression values of the AMPA-GluR2 protein and AMPA-GluR2 mRNA were significantly increased in the cytidine diphosphate choline group compared with the normal saline solution group (protein0.52 ± 0.04 vs.0.33 ± 0.03,t =8.497,P ＜ 0.05 ; mRNA0.48± 0.04 vs.0.33 ± 0.02,t =7.500,P＜0.05).Conclusions AMPA-GluR2 is associated with the plasticity of visual development.Levodopa and cytidine diphosphate choline may improve visual function by down-regulating the expression of AMPA-GluR2 in the visual cortex.