双眼形觉剥夺后成年大鼠视皮层可塑性再激活模型建立

Model of reactivating visual cortex plasticity after binocular form deprivation in adult rats

目的建立成年大鼠双眼形觉剥夺(binocular form deprivation,BFD)后视皮层可塑性再激活模型。方法记录出生后3周龄(postnatal 3 weeks old,PW3)至PW7的Long-Evans大鼠的双眼视觉诱发电位(visual evoked potential,VEP),然后将右眼进行单眼剥夺3d、5d和7d后再次检测双眼VEP。采用PW7大鼠进行BFD7d、10d和14d,在下次检测VEP前将左眼打开3d、5d和7d。结果3d的单眼剥夺降低了PW3、PW4和PW5大鼠的C/I比值(被遮盖眼对侧眼的VEP振幅/同侧眼VEP振幅),分别为0.71±0.13(P<0.01)、1.21±0.17(P<0.05)和1.06±0.19(P<0.01);但PW6和PW7大鼠的C/I比值没有变化(1.63±0.18,P>0.05和1.55±0.13,P>0.05),证实成年大鼠眼优势可塑性的消失。然而,对于BFD14d后的PW7大鼠,我们可以观察到3d的单眼剥夺可以造成C/I比值的明显降低(0.77±0.17,P<0.01),说明成年大鼠眼优势可塑性的再激活。结论BFD可成功激活成年大鼠视皮层眼优势可塑性,此模型的建立为成年弱视治疗的进一步研究奠定了理论基础。

Objective To build the model of reactivating visual cortex plasticity after binocular form deprivation（BFD） in adult rats. Methods Visual evoked potentials（VEP） of both eyes were recorded in Long-Evans rats aged from postnatal 3 weeks old （ PW3 ） to PW7, and recorded again after monocular deprivation （MD） for 3 days, 5 days, and 7 days, respectively,in the right eyes. Rats of PW7 were treated with BFD for 7 days,10 days or 14 days,and then left eyes were opened for 3 days,5 days or 7 days before the next VEP recording. Results MD for 3 days decreased C/I ratio （ contralateral VEP amplitude to ipsilateral VEP amplitude in occluded eyes） in rats of PW3, PW4 and PWS,which were 0.71 ± 0. 13 （P 〈 0.01 ）, 1.21 ± 0. 17 （P 〈 0.05 ） and 1.06 ± 0. 19 （ P 〈 0.01 ）, respectively, but not changed in those of PW6 and PW7 （ 1.63 ± 0. 1 E, P〉0.05 and 1.55 ±0.13,P〉0.05） ,confirming the absence of ocular dominance （OD） plasticity in adults. However, for rats of PW7 with BFD for 14 days, a significant decrease was observed in the C/I ratio in rats with MD for 3 days（0.77± 0.17 ,P 〈 0.01 ）, demonstrating the reactivation of OD plasticity in adult rats. Conclusion BFD can successfully reactivate the OD plasticity in adult visual cortex, which can provide a theoretical basis for the treatment of adult amblyopia.