发育期单眼形觉剥夺弱视模型猫P-VEP的特征

Characteristics of pattern visual evoked potential in monocular visual deprivation amblyopia cat model at developmental phase

目的观察单眼形觉剥夺性弱视动物模型视皮层的电生理特性,探索弱视发生的皮层机制,并为弱视的治疗提供实验依据。方法11只初生家养猫随机分为2组,处理组在3周龄时缝合单侧眼睑塑造单眼形觉剥夺性弱视模型,3个月后以图形视觉诱发电位(pattern visual evoked potential,P-VEP)技术检测视觉生理功能的改变。结果对照组双眼间的P-VEP波形潜伏时和振幅差异无统计学意义(P>0.05),而处理组剥夺眼的P波潜伏时延迟和振幅降低或呈波形熄灭的杂波,与对侧健眼及对照组比较,差异均具有显著统计学意义(0.01<P<0.025、P<0.005)。对照组P波的振幅随刺激的空间频率增加而增高,在达到0.10c.d-1时后转呈下降趋势,而潜伏时却始终随空间频率增加而延迟。处理组双眼P波潜伏时和振幅均缺乏与刺激空间频率的对应关系。结论单眼形觉剥夺性弱视动物模型视皮层的电生理特性出现异常,说明弱视的发生存在皮层机制。

Objective To explore the cortical mechanism of amblyopia and provide the studying evidence of possible treatment for amblyopia through the observation of electrophysiological characteristics of visual cortex in monocular visual deprivation amblyopia models. Methods Eleven new born domesticated cats were randomly divided into two groups. The treatment group was treated with eye lid suture to produce monocular visual deprivation at 3 weeks of age, and the changes of visual physiological function were measured with pattern visual evoked potential （P-VEP） 3 months later. Results In control group, the difference of latent time and amplitude between the right eye and left eye was not significant （P 〉 0.05 ）. The P-VEP evoked through the operated eyes manifested that the latent time of P-VEP delayed and its amplitude decreased, or there was pigeons as extinct waveform in treatment group;Either compared with contralateral eyes or control eyes were significant （ 0.01 〈 P 〈 0. 025, P 〈 0. 005 ）. Amplitude of P wave increased with the increasing of spatial frequency, and then decreased when spatial frequency came to 0.10 c · d^-1 ;While the latent time was always delayed with the increasing of spatial frequency in control group. There was no correspondence of latent time and amplitude of P wave with spatial frequency in treatment group. Conclusion Monocular visual deprivation affects the characteristics of P-VEP,which suggests that the occurrence of amblyopia has the cortical mechanism.