A Study On The Visual Cortex Area 17 Plasticity Of Form Deprivation Tree Shrew

Objective:To explore the feasible reseach analysis of tree shrew as a new kind of amblyopia model; To observe the expression change in visual cortex area 17 c-fos protein and c-fos mRNA, visual cortex histology, changes in ultrastructure and apoptosis of form deprivation tree shrew; Preliminary discussion on the visual cortex area 17 plasticity mechanism of form deprivation tree shrew, to provide a theoretical basis for further understanding of amblyopia formation and the recovery mechanism.Methods:Sixty tree shrews 30 days old were divided for five groups, there are 12 in each group:the group right eye sutured for 1 month(group A); the group right eye sutured for 2 months(group B); the group left eye sutured for 1 month after opening right eye which is sutured for 1 month(c), or in other words, the group by alternating suture; control group 1 (D1), tree shrews of A group the same old in the normal breeding environment; control group 2 (D2), tree shrews of B, C group the same age feeding in normal condition.To position and draw materials in visual cortex after Modeling is completed and visual cortex area 17 can be located by Nissl staining; To observe the pathological changes histologically, the presence of apoptosis cell by apoptosis (TUNEL) staining, the changes of neuronal ultrastructure by transmission electron microscope, c-fos protein expression by immunochemistry and c-fos mRNA expression changes by real-time fluorescence quantitative polymerase chain reaction (RT-PCR) in experimental visual cortex; Finally we analyze the results.Results:Damage of different degrees were found in the histological and electron microscopic studies of the visual cortex in each experimental group, and it was more obvious in the group sutured with 2 months; Apoptosis staining showed that there were 1-2 apoptosis positive cells in the experimental groups and the control groups, and have no difference among the groups; The expression of c-fos protein and mRNA in the experimental groups showed decreased, it was the lowest in the sutured goup for 2 months, there was a small increase in the expression after the change of suture, and no significant difference of c-fos expression was found in the control groups.Conclusion:1.Pathological changes of mild to moderate amblyopia visual cortex area 17 may be multifocal neurons atrophy, decrease in the number of neurons with gliosis; pathological alteration of severe amblyopia may be multifocal neurons atrophy, the quantity of nerves reduced, glial cell proliferation, accompanied by visual cortex small focal spongiform degeneration and parts of the vertebral body cell degeneration or edema; hyperplasia of glial cells may be pathological basis of amblyopic recovery.2.Form deprivation amblyopia did not cause apoptosis of neuronal cells.3.C-fos gene may be involved in the formation and recovery of amblyopia.4.There is plasticity in the neuronal damage induced by amblyopia.5.The tree shrew can be used as an ideal animal model for the form deprivation amblyopia.