Abstract: Objective This study was designed to observe the cognition of Fmr1 knockout mice at 30 days Age in step-down test. Method Fmr1 knockout mice were identified using the PCR technical and step-down test were used in the study. Animals were tested for two days. The latency and the number of errors were recorded. The data was analyzed with Multifactor Variance Analysis. Result KO mice obviously had the shorter latency than WT mice, and KO mice obviously had more errors than WT mice (P<0.05); On the first day, the latency and the number of errors of KO mice had no difference compared with the second day (P>0.05); On the first day, the latency and number of errors of WT mice had significant difference compared with the second day (P<0.05). Conclusion Fmr1 knockout mice displayed cognitive impairment in the step- down test.

Key words: step-down test, Fmr1, knockout, mice, cognition;

摘要： 目的 对30日龄的Fmr1基因敲除小鼠的跳台实验进行观察。方法 采用30日龄的KO鼠和WT鼠分别连 续进行2d的跳台实验，根据所获得的数据进行多因素方差分析处理。结果 同周龄KO鼠的潜伏期比WT鼠明 显少(P＜0.05)；而KO鼠的错误次数比WT鼠明显多(P＜0.05)；不同周龄KO鼠或WT鼠的潜伏期、错误次数无 差异(P＞0.05)；第1天KO鼠的潜伏期和错误次数与第2天相比无差异(P＞0.05)；第1天WT鼠的潜伏期和错 误次数与第2天相比有显著差异(P＜0.05)。结论 30日龄Fmr1基因敲除小鼠存在认知功能障碍。

关键词: 跳台实验, Fmr1, 基因敲除, 小鼠, 认知