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. Key words: Mouse;  Visual electrophysiology;  Pattern electroretinogram