30日龄脆性X基因敲除小鼠的被动回避行为观察

目的观察30日龄的脆性x基因（Fmrl）敲除小鼠（KO鼠）的被动回避行为。方法选取Fmrl基因敲除型（KO）纯合子（-／-）及其野生型（wT）纯合子（＋／＋）FVB近交系小鼠3013龄各15只，采用PCR鉴定实验动物KO鼠和wT鼠的基因型，进行2d的被动回避行为的避暗和跳台实验，比较2组小鼠电击次数和潜伏期时问。结果避暗实验中，第1天KO鼠的电击次数为（8．28＋0．50）次，与wT鼠（7．10±0．46）次相比显著增多（P〈0．05）；潜伏期时间虽增加但差异无统计学意义。第2天KO鼠的电击次数及潜伏期时间与wT鼠相比，差异均无统计学意义。KO和wT鼠第1天与第2天的潜伏期和电击次数相比，差异均有统计学意义（均P〈0．05）。跳台实验中，第1天KO鼠的潜伏期为（94．96±10．56）s，比wT鼠（135．73±12．17）s明显缩短（P〈0．05）；而电击次数为（1．81±0.31）次，比wT鼠（O．67±0．13）次明显增多（P〈O．05）。第2天KO鼠的电击次数及潜伏期时间与wT鼠相比，差异也无统计学意义。第1天wT鼠的电击次数与第2天相比，差异无统计学意义，潜伏期则低于第2天（P〈O．05）；而第1天KO鼠的潜伏期和电击次数与第2天相比，差异有统计学意义（均P〈O．05）。结论30日龄Fmrl基因敲除小鼠存在认知功能障碍。

Passive avoidance in Fmr1-knockout mice at 30 days of age

Objective To investigate the passive avoidance behavior in Fmrl-knockout （KO） mice at 30 days of age. Methods Fmrl-KO mice（-/-, n=15） and wild-type FVB inbreeded （WT） mice （＋/＋, n= 15） at 30 days of age were allocated and subjected to genotyping by using polymerase chain reaction. Step- through and step-down tests were conducted for measurement of latency period and the number of electric shocks. Results During the step-through test, KO mice had higher incidence of electric shocks （8.28＋0.50 vs 7.10~0.46, P〈0.05） than WT mice at day 1. There was an increased trend of latency period, but the between-group difference did not reach statistical significance. At day 2, there was no marked between-group difference in the latency period and number of electric shock. Additionally, the latency period and number of electric shock did differ considerably between day 1 and day 2（all P〈0.05）. During the step-down test, KO mice yielded impressively shorter latency period （94.96＋10.56）s vs （135.73＋12.17）s, P〈O.05 ] yet higher incidence of electric shock （1.81＋0.31 vs 0.67＋0.13, P〈0.05） compared with WT mice. Between-group difference in the latency period and the number of electric shock did not reach statistical significance at day 2. There was no significant difference in the number of electric shock of WT mice between days 1 and 2. Thelatency period of WT mice was shorter than that at day 2（P〈0.05）. However, the latency period and number of electric shocks of KO mice differed significantly between days 1 and 2 （all P〈0.05）. Conclusion Fmrl- knockout mice at 30 days of age may have developed cognitive impairment.