正常C57BL/6J小鼠明视紫外光视网膜电图特征

目的观察小鼠紫外光敏感视锥系统（UV-cone）视网膜电图（ERG）的特点。方法实验研究。成年野生型C57BL/6J小鼠10只（10眼），随机分成实验组和对照组，每组5只。2组均明适应（背景白光的色温为7000 K，亮度为30 cd·m^-2） 10 min后行ERG检测。实验组记录UV-cone ERG，刺激所用的紫外光波长为363 nm，刺激强度分别为0.03、0.30、1.00、3.00 mW·s·m^-2。对照组记录明视系列白光ERG。2组间最大反应a波、b波振幅的比较采用独立样本t检验。结果实验组紫外光（UV）刺激强度达到0.30 mW·s·m^-2时，ERG开始出现稳定的正向b波，其振幅为（14.8±3.0）μV；随着刺激强度增大，b波上可以记录到明显的振荡电位（前3个子波振幅较大）。而对照组b波上未见明显的振荡电位。实验组ERG最大反应b波振幅明显高于对照组（t=2.615，P＜0.05），而a波振幅2组间差异无统计学意义（t=-1.633，P＞0.05）。结论正常成年C57BL/6J小鼠明视UV-cone ERG与传统的白光ERG在波形和最大反应幅值上存在一定的差异。

Characteristics of photopic ultraviolet-sensitive cone electroretinograms in C57BL/6J mice

Objective To observe the characteristics of photopic ultraviolet-sensitive cone electroretinograms （UV-cone ERGs） in C57BL/6J mice. Methods This was an experimental study. Ten adult wild-type C57BL/6J mice （10 eyes） were divided into 2 groups of 5 each. Photopic ERGs were elicited after 10 minutes of adaptation under a steady white background illumination of 30 cd·m^-2. Mice in the experimental group displayed UV-cone ERGs elicited by UV flashes （λ=363 nm） with stimulus intensities of 0.03 mW·s·m^-2， 0.30 mW·s·m^-2，1.00 mW·s·m^-2 and 3.00 mW·s·m^-2. Mice in the control group displayed white flash ERGs （stimulus intensities ranged from 0.02 to 10.00 cd·s·m^-2）. The maximum responses of the a- and b-wave amplitudes of the 2 groups were compared. An independent samples t test was used for statistical analysis. Results As UV intensity increased to 0.30 mW·s·m^-2， the UV-cone ERG could be elicited with an amplitude of 14.8±3.0 μV. At an intensity of 1.00 mW·s·m^-2 or 3.00 mW·s·m^-2， oscillatory potentials （OPs） with a sizeable O_1-3 were recorded on the b-wave. But there were no obvious OPs in the control group. The maximum response showed that the b-wave amplitude of the experimental group was significantly higher than that of the control group （t=2.615， P＜0.05）， although there was no statistically significant difference in a-waves （t=-1.633， P＞0.05）. Conclusion In adult C57BL/6J mice， the difference between photopic UV and white flash ERGs involve wave shape and maximum amplitude. Our results provide normal reference values for UV-cone ERGs in mice.