The Expression Of NogoA In 21a Area Of Visual Cortex In Strabismic Amblyopia Cats

ObjectiveTo investigate expression of NogoA, a neurite growth inhibitor, in 21a Area ofvisual cortex in strabismic amblyopia model and the model treated with natural herbA.The possible mechanism of strabismic amblyopia and therapeutic effect of naturalherb A are discussed.MethodsLateral recti of cats were cut to form the model of the esotropia in the left eye.After that, the cats were raised for 1 week and were assured the formation ofamblyopia by P-VEP. Then the cats were divided randomly into 4 groups: strabismicgroup, control group, low-dose group, high-dose group compared with normal group,each group had four cats.The cats in the low-dose group and the high-dose group were daily injected withthe natural herb A of 10mg/kg and 30mg/kg for seven days separately.; the fight eye ofthe cats in the control group were sutured as a model of patch therapy for one week.P-VEP was examined for all groups.The cats in each group were killed.The visual cortex 21a area of right brain wereobtained to observe morphology and immunohistochemistry.The data about VEP and immunohistochemistry, was analyzed by two independentsamples t-test between the normal group and the strabismus group with SPSS10.0.Except the strabismus group, the correlations between the other groups was analyzedwith variances.Results1. Electrophysiology: the strabismic group is characterized with the decreased amplitudes of the P₁₀₀ waves. The P₁₀₀ latency is not delayed obviously. Theamplitudes of the left eye/right eye are no significant difference compared with thenormal group (P=0.120, P=0.960) in the low-dose group and the high-dose group; theP₁₀₀ latency is advanced obviously in high-dose group(P=0.049).2. Morphology: compared with the control group, numbers of neuron in thestrabismic group decrease obviously. Furthermore, most of them, volume of neuron issmaller, the neuron is getting round, ecphyma of neuron is getting shorter ordisappearance. Some nucleus of neurons are smaller and darkening. To some extent,the neurons are recovered in the low-dose group, the high-dose group and the controlgroup. The volume of neuron is bigger and the axon is partly recovered.3. Compared with the normal group, the expression of NogoA is significantdifference in the strabismic group(P＜0.05). The expression in the high-dose group issimilar to the normal group and no significant difference isfound(P=0.529,P=0.984,P=0.507). Compared with the normal group, there issignificant difference between the control group and the low-dose group(P=0.000,P=0.000,P=0.000).Conclusions1. There is significant increase of the expression of NogoA in the strabismicgroup compared with the normal group. It indicates that NogoA may play animportant role in formation of amblyopia.2. There is significant decrease of the expression of NogoA in the high-dosegroup with natural herb A. It suggests that the improved visual function ofamblyopia may be brought into effect through NogoA expression.