神经示踪染料DiI影响UC小鼠DRG神经元电学特性

Tracing dye DiI affects the electrical properties of DRG neurons in UC mice

摘要:

【目的】 探究在神经示踪结合膜片钳全细胞记录的实验中,示踪染料DiI是否会对小鼠背根节神经元(Dorsal Root Ganglion DRG)兴奋性产生影响。【方法】 采用SPF级雄性C57BL/6J小鼠,经5%葡聚糖硫酸钠(Dextran Sulfate Sodium,DSS)诱导溃疡性结肠炎(Uicerative Colitis,UC)模型,在T12-L2皮节多点注射DiI逆向示踪躯体感觉神经元,分离全组织背根神经节并进行全细胞膜片钳记录。【结果】 HE染色结果显示模型诱导成功。膜片钳记录未经标记的动物DRG神经元,模型组小鼠膜电位兴奋性高于正常组动物。两组动物示踪后,正常示踪组和模型示踪组DiI+神经元兴奋性均低于本组DiI-神经元；模型组DiI+神经元和DiI-神经元兴奋性均低于正常示踪组相应神经元。两示踪组小鼠DiI-神经元与未示踪小鼠DRG神经元比较,兴奋性升高。【结论】 我们的实验结果明确了示踪剂DiI对背根节神经元兴奋性存在以降低为主的影响,提示在相关实验设计中应避免示踪剂的影响掩盖动物模型引起的神经元兴奋性改变。

Abstract:

【】 Objective To investigate whether the tracer dye DiI affects the excitability of dorsal root ganglion (DRG) neurons in mice in an experiment applying neural tracing combined with patch clamp technique. Methods The SPF-grade male C57BL/6J mice were treated by 5% DSS induced ulcerative colitis, and DiI was injected at multiple points in T12-L2 dermatomes to retrogradely label somatosensory neurons. Whole mount DRG were isolated and subjected to whole-cell patch clamp recording. Results In the H E staining, the colonic mucous glands of model group was structure destruction. Excitability of the cell membrane from the mice in model group was higher than that from the blank control group. In the group treated with DiI, excitability of DiI+ neurons in the Con+DiI and DSS+DiI groups was lower than that of DiI- neurons in the same group; the excitability of DiI+ neurons and DiI- neurons in the DSS+DiI group was lower than that of the corresponding neurons in the Con+DiI group, respectively. DiI- neurons in the Con+DiI group of mice showed elevated excitability compared to DRG neurons in mice of Con+DiI group. Conclusion Our results demonstrated that DiI mainly reduces the excitability of dorsal root ganglion neurons, suggesting that the influence of tracer should be avoided in the design of relevant experiments for the reason that it may mask the changes in neuronal excitability caused by animal models.