p53基因敲除对小鼠神经行为及桶状皮层神经元数目的影响

Effects of p53 gene knockout on neurobehavior and neuron number in barrel cortex in mice

目的探究p53基因在小鼠神经行为活动中的作用及对桶状皮层神经元数目的影响。方法45只8~12周龄C57BL/6背景的p53基因敲除(KO)小鼠为实验组,38只同年龄同背景的野生型(WT)小鼠为对照组。通过旷场实验、Y迷宫实验和纹理辨别实验测试小鼠焦虑样行为、自发运动、工作记忆能力及触须敏感性。用尼氏染色法观察桶状皮层II/III层神经元数目变化。结果与WT小鼠相比,p53基因敲除小鼠在旷场中心活动的时间(P>0.05)、旷场中总运动路程(P>0.05)和Y迷宫中自发交替率(P>0.05)、进入臂的总次数(P>0.05)均无显著差异,但对新纹理目标物的探索百分比显著减少(P<0.01);p53基因敲除小鼠桶状皮层II/III层的神经元数目较野生型小鼠显著减少(P<0.01)。结论p53基因缺失不会导致小鼠出现焦虑样行为、也不影响其自发运动及工作记忆能力,但损伤了小鼠对新纹理的辨别能力,即触须敏感性,可能与桶状皮层II/III层神经元数目减少有关。

Objective To investigate the role of p53 gene in neurobehavior activities and effects on the number of neurons of barrel cortex in mice.Methods A total of 458~12 weeks old p53 knockout(KO)mice with C57 BL/6 background and 38 wild-type(WT)mice of the same age and background were included as the experimental group and the control group,respectively.The open-field test,Y-maze test and texture discrimination task were used to evaluate anxietylike behavior,locomotor activity,working memory and whisker sensitivity in mice.Nissl staining was used to observe changes in neuronal numbers in layer II/III of barrel cortex.Results Compared with WT mice,p53 KO mice did not show any significant difference in the time spent in the center(P>0.05)or total distance moved(P>0.05)of the open field apparatus,the percentage of spontaneous alternations(P>0.05),and the numbers of arms entries(P>0.05)in the Ymaze test.However,the percentage of time exploring objects with novel texture was significantly decreased(P<0.01).The number of neurons in layer II/III of barrel cortex of p53 KO mice was significantly reduced compared with that of WT mice(P<0.01).Conclusions Deletion of p53 gene did not lead to anxiety-like behavior in mice.Moreover,locomotor activity and working memory were not affected by p53 deletion.However,p53 deletion impacted the ability to discriminate novel textures,that is,whisker sensitivity,which may be related to the decreased number of neurons in layer II/III of the barrel cortex.