The Effect Of Enriched Environment On NMDA Receptor At The 17th Area Of Adult Amblyopia Rats's Visual Cortex

PurposeTo explore the effect of enriched environment on the level of NMDA receptors NR2A and NR2B subunit which belongs to glutamate receptors with excitability at the 17th area of amblyopia rats's visual cortex after critical period. In order to understand the possible mechnism of synaptic plasticity of adult amblyopia rat visual cortex.MethodsThe Wistar rats were devided into normal group and experimental group. In the research groups, the right eyelids of rats were sutured through the whole critical period in order to establish the model of monocular deprivation amblyopia rat. All researched rats, except the normal ones, were divided into amblyopia group, standard environment group and enriched environment group on P45 in random. The sutured right eyelids were opened on P46 in the standard environment group and enriched environment group. All the rats were sacrificed to get the 17th area of the left visual cortex on P60, P75, and P105. Three rats were used in research at different times from each group.Ⅰ～Ⅵlayer of visual cortex area 17 were observed using HE staining. The expression of NMDA receptors NR2A and NR2B subunit was detected by Immunohistochemistry. Integrated optical density (IOD) of NMDA receptors NR2A and NR2B subunitand were detected by using special image analysis software (image proplus 6.0). SPSS 16.0 for windows was used to get the statistical results.ResultsExpressions of NMDA receptors NR2A subunit in visual cortex of rats at different times from each group:The expression of NMDA-NR2A subunit in P60,P75 and P105 from four groups have statistical sense. Amblyopia can lead to NMDA-NR2A expression in visual cortex reduced. The expression of NMDA-NR2A was stronger than that in the amblyopia group by intervention 15d,30d,60d with the rich environments, but did not reach normal level.Expressions of NMDA receptors NR2B subunit in visual cortex of rats at different times from each group:The expression of NMDA-NR2B subunit in P60% P75 and P105 from four groups have statistical sense. Amblyopia can lead to NMDA-NR2B expression in visual cortex increased. The expression of NMDA-NR2B was weaker than that in the amblyopia group by intervention 15d with the rich environments, but did not reach normal level. the expression of NMDA-NR2B subunit after intervention 30d and 60d was reach normal levels.ConclusionsThe plasticity of visual cortex exists not only in the critical period but also after the critical period of visual development.Enriched environment, as a non-invasion method, can improve and recover the synaptic plasticity in visual cortex of adult rats.