磨牙缺失对幼年大鼠空间学习记忆能力的影响

目的：探讨不同磨牙缺失数对幼年大鼠空间学习记忆能力的影响。方法：健康幼年大鼠60只随机分成3、6、9、12颗磨牙缺失组、麻醉对照、正常对照6组。在造模后1周,采用Morris水迷宫系统测试各组大鼠学习记忆能力,每周1次,连续6周。结果：9颗、12颗磨牙缺失组间大鼠游泳平均逃逸潜伏期（the swimming average escape latency,SAEL）无明显差异,但均显著高于其它4组（P〈0.001）;6颗磨牙缺失组大鼠与3颗磨牙缺失组、麻醉组及正常对照组间SAEL比较有差异（P〈0.05）;3颗磨牙缺失组、麻醉组及正常对照组组间SAEL比较均无显著性差异。各磨牙缺失组大鼠随着磨牙缺失数目的增多tP/tT值有逐渐下降趋势,各组间比较差异有统计学意义（P〈0.05）,但3颗磨牙缺失组与正常组及麻醉组间tP/tT值无明显差异,其他各磨牙缺失组与正常组及麻醉组间tP/tT值均有差异（P〈0.05）。结论：较多数目磨牙缺失会对幼年大鼠空间学习记忆能力造成不同程度的损伤,而个别磨牙缺失对幼年大鼠空间学习记忆能力无显著性影响。

Effect on Spatial Learning and Memory Ability in Young Rats of Molar--missing

Objective： To investigate the effect on spatial learning and memory ability（SLMA） in young rats of dif- ferent molar--missing number. Methods： 60 healthy and young rats were randomly divided into the following six groups： the number of 3, 6, 9 and 12 molars--missing experimental control groups, no molar--missing in anes- thetic control group and blank control group. These rats underwent the Morris Water Maze test for six weeks with once perweek after management. Results： There is not significant different on swimming average escape latency （SAEL） between the number of 9 and 12 molars--missing rats groups, but they are significantly higher than other 4 groups （P〈0. 001）. Comparing the number of 6 molars--missing group to the number of 3 molars--missing group, anesthetic control group and blank control group, there is significantly different on SAEL （P〈0.05）. Com- paring among the number of 3 molars--missing group, anesthetic group and blank control group, there is not sig- nificant different on SAEL. The tP/tT ratio gradually decreases as the number of molar--missing increasing in four experimental control groups, and there is significant difference among four groups （P〈0.05）. But the tP/tT ratio dose not show significant difference among the number of 3 molars--missing group, blank control group and anes- thetic group. There is significant different on tP/tT ratio, comparing other 3 expeimental control groups to blank control group and anesthetic group（P〈0.05）. Conclusion： The SLMA will be damaged caused by the majority of molar--missing in young rats, while there is not significant effect for the minority of molar--missing.