小鼠图形视网膜电图记录方法探讨

背景 由于小鼠与人类基因的高度同源性和眼病的高度相似性,小鼠已更多地用于人的眼病模型,视网膜电图(ERG)作为无创性检查手段,是评价小鼠眼病模型视功能不可替代的手段,但目前实验中多采用闪光ERG(FERG)进行检查,只能评价视网膜外层的功能,采用图形ERG(PERG)评价小鼠视网膜内层功能的研究较少. 目的 探讨小鼠PERG的记录方法、波形特点及影响因素,为视觉电生理在小鼠眼模型研究中的应用提供依据. 方法 6周龄清洁级雄性C57BL/6N小鼠30只,采用德国RETLport视觉生理检测系统进行PERG检测,记录电极为自制针灸针电极,置于角膜缘,参考电极和地电极分别置于颊部和尾部皮下,明适应状态下记录小鼠不同时间频率(0.5、1.0、2.0、4.0 Hz)、不同空间频率(0.05、0.10、0.20 cpd)下的PERG,分析同一时间频率和空间频率组合下不同对比度(95％和99％)、不同通频带(1～ 100 Hz、5～ 30 Hz)设置对小鼠PERG的影响,探讨PERG不同的参数设置对小鼠PERG记录结果的影响. 结果 正常成年小鼠PERG波形趋势较为明显,N1波约出现在37 ms,P波约出现于86 ms,N1-P波振幅值为2～6 μV.不同的空间频率、时间频率及对比度的设置均影响小鼠电生理的幅值,其中时间频率分别为0.5、1.0、2.0、4.0Hz时,所测得的N1-P波的振幅均值分别为(3.40±0.71)、(5.08±0.88)、(3.21±1.54)、(3.85±1.96) μV,差异有统计学意义(F=7.43,P=0.00).在电磁波干扰明显时,通频带设置在5～ 30 Hz时可以得到质量较好的波形,并不影响其记录的振幅值.刺激屏对比度设置为99％、叠加次数为200次时可记录到明显而稳定的波形. 结论 成年小鼠PERG波形以及变化趋势与人类较为相似,PERG可以作为在体评价小鼠视网膜内层功能的指标用于眼科的实验室研究,合理的参数设置和标准化记录条件可提高记录结果的可比性和可靠性.

Recording method of mouse pattern electroretinogram

Background Mouse has been used in laboratory studies as the model of ocular diseases.Electroretinogram (ERG)is a non-invasive method for primary examination to evaluate retinal function.Though flash ERG has been widely applied in the mouse ocular disease model for the functional assessment of the retinal outer layer,pattern ERG(PERG) is seldom used for inner retinal evaluation. Objeetive The present experimental study was to investigate the recording parameters and method,wave characteristics of PERG and influencing factors in mouse,and to build the foundation for further research. Methods Thirty C57BL/6 mice aged 6 weeks old were included in this research.RETLport ( Roland Consult,Germany) was adopted for the recording of PERG.The positive needle electrode was placed in the cornea,and the reference and earth electrodes were placed under the derma in the cheek and tail.The PERG under different temporal frequencies (0.5,1.0,2.0 and 4.0 Hz),and special frequencies (0.05,0.10,0.20 cpd) were recorded in a photopic environment,and different contrast ratio (95％ and 99％ ) of stimulator or different transmission bands ( 1-100 Hz,5-30 Hz) in the same temporal frequency and spatial frequency were regulated to analyze the influence on mouse PERG.The use of animals was in compliance to the Regulations for the Administration of Affairs Concerning Experimental Animals by the State Science and Technology Commission.Results The latency of N1 PERG showed a negative N1wave at around 37 ms and positive P wave at about 86 ms in adult mice.The amplitude of N1-P was 2-6 μV.Different spatial frequency,temporal frequency and contrast can affect the final results,and the different temporal frequencies were statistically significant.The wave was stable and the amplitude was unaffected at 5-30 Hz transmission bands with pronounced interference (mean amplitude of N1-P waves were(3.40±0.71),(5.08±0.88),(3.21±1.54),(3.85±1.96)μV in 0.5,1.0,2.0,4.0 Hz,F=7.43,P=0.00). Conclusions PERG wave from adult mouse is similar to that from human.It is a useful method in evaluating the inner retinal function.Appropriate stimulating parameters are critical for recording.