多电极阵列记录技术在大鼠视网膜生理研究中的应用

目的 采用多电极阵列（MEA）技术探索记录Sprague-Dawley（SD）大鼠视网膜电生理特征的方法。方法 实验研究。采用成年清洁级雄性SD大鼠6只。处死后急性分离出视网膜神经感觉层，将其转移到MEA生物芯片上，使神经节细胞一面贴于电极阵列，用充氧的Ringer′s液孵育15 min后，记录不同光照刺激或电刺激模式下大鼠视网膜电生理特征。所有数据经Shapiro-Wilk检验呈正态分布，以x±s进行描述。结果 MEA能够记录到SD大鼠视网膜典型的光刺激诱发场电位改变，这种光诱发场电位的幅值随刺激光亮度增加先增大后稳定。暗适应后给予高光亮度（256 cd/m2）刺激时，长时程光照后（6～10 s），可记录到一个明显的撤光相关场电位改变，表现为一个负向偏折。根据光诱发神经节细胞的放电模式与光刺激的关系，可将神经节细胞分为ON、OFF及ON/OFF型。电刺激诱发神经节细胞的放电主要集中在刺激后的50 ms内。结论 MEA技术可以在保证视网膜神经回路完整的情况下，从多个方面（感觉细胞、双极细胞、神经节细胞3个水平）对视网膜的功能做出客观的评定。

Research on the physiological function of the rat retina with a multi-electrode array

Objective To investigate the physiological function of the isolated rat retina with a multi-electrode array （MEA） system， and develop a more comprehensive method to evaluate retinal function in animals. Methods In this experimental study， retinas were isolated from 6 Sprague-Dawley （SD） rats， and placed into the recording chamber with the ganglion cell layer facing the biochip electrode array. Retinas were perfused with aerated Ringer′s solution for 15 minutes before recording. Then light-evoked or electrical current-evoked responses of the retinal cells were recorded with an MEA system. The obtained data were analyzed with a Shapiro-Wilk test， and the values were presented as a mean±standard deviation. Results Typical light-evoked responses were successfully recorded. The amplitude of the field potential became higher as the luminance increased （<256 cd/cm2）. The results also showed that the off-light responses were obtained when the duration of the light stimulus was changed from 6 to 10 seconds. The light-off response was a low amplitude negative wave at the offset of the light stimulus. Moreover， according to the peristimulus time histograms （PSTHs） and raster plots of individual units， the retinal ganglion cells （RGCs） were categorized as either ON， OFF， or ON-OFF. In addition， the responses of RGCs evoked by electrical current usually occurred within 50 ms post stimulus. Conclusion The MEA can be used to assess the retinal function of animals more comprehensively from different neurons （photoreceptor， bipolar cell and RGC）