正常大鼠视网膜电图振荡电位的频谱特性分析

Frequency spectrum analysis of dark-adapted oscillatory potentials in normal rats

背景暗适应视网膜电图（ERG）的振荡电位（OPs）在多种视网膜疾病的视功能评价中发挥重要作用，但其波形的确切起源尚未完全明确。OPs波的时域和频域分析及其影响因素的研究对进一步研究OPs的发生和起源具有重要意义。目的观察正常大鼠的暗适应ERGOPs与刺激光强度和动物年龄的关系。方法选择出生后21、25、32、35、37、46、60及90d的RCS—rdy^＋-P^＋大鼠各3只，采用RETI—scan记录系统进行闪光视网膜电图（F—ERG）OPs波记录，记录电极为环形角膜电极，参考电极为不锈钢针状电极，刺激强度分别为-20、-10、-5、0、5dB，通过Matlab提取OPs成分，分析其频谱特性。结果上述各种刺激强度下不同年龄组大鼠OPs的最大能量振幅值对应的频率值（即主频）范围为80～120Hz。随着刺激光强度的增加，开始出现高频（200—250Hz）成分，对应的振幅值随着刺激光强度的增加而增加；低频成分，即主频随着刺激光强度的增加其对应振幅值出现先升高后下降的趋势；当刺激光强度达到0dB时，低频成分出现双峰现象。25日龄大鼠OPs主频振幅最小，60日龄大鼠OPs主频振幅最大；25日龄大鼠OPs主频的带宽最窄，60日龄大鼠OPs主频的带宽最宽。结论大鼠ERG的OPs频域特性分析说明，刺激光强度对大鼠OPs振幅产生正向的影响，而大鼠的年龄主要影响OPs的主频分布。

Background Oscillatory potentials （OPs） of scotopie eleetroretinogram （ERG） plays an important role in the evaluation of visual function in multiple retinal diseases. However,the origin of OPs is uncompletely clear. It is essential to analyze the time domain and frequency domain components for the further study of OPs. Objective The present study was to investigate the change characteristics of frequency spectrum of scotopie OPs with age and stimulating intensity. Methods RCS-rdy＋-p＋rats with the ages of 21,25,32,35,37,46,60,90 days were selected in this study and 3 rats for each. Scotopic flash ERG were recorded from all the rats with RETI-scan system. Gold-foil ring cornea recording electrode was used as the recording electrode and the steel needle electrode was used as the reference and earth electrode during the record. The intensity of stimulating light was set at -20,-10,-5,0 and 5 dB respectively. Data were output into the computer and processed by the software Matlab7.0. Results The principle frequency corresponding to maximum amplitude component was 80-120 Hz in the various ages of rats under the different stimulating conditions above. With the increase of the intensity of stimulating light, high frequency component （200-250 Hz） began to appear and the amplitudes showed a gradually raise upon the intensity of light. The major component was subdivided into two peaks at 0 dB stimulation. Further, the age affected the major frequency peak with the maximum value at 60-day-old rats and the minimum value at 25-day-old rats. Also,the pass-band width of main amplitude appeared to be maximal at 60-day-old rats and minimal at 25-day-old rats. Conclusions OPs in Res- rdy＋-p＊ rats are influenced by stimulating intensity and age. Stimulating intensity affects the amplitude and age lead to the change of distribution of primary frequency of OPs. It is possible to know the influences of the degeneration of rods and be helpful to diagnosis this kind of disease.