摘要
探讨了小鼠孕期和哺乳期饲喂轻度缺锌饲料对仔鼠学习记忆能力的影响．实验动物为成年雌性ICR小鼠30只及其所产的仔鼠30只．怀孕母鼠随机分为3组：（A）对照组；（B）孕期及哺乳期轻度缺锌组及（C）孕期轻度缺锌组．对照饲料及轻度缺锌饲料的锌含量分别为100mgZn／kg和5mgZn／kg。A组小鼠饲喂对照饲料；B组小鼠孕期及哺乳期皆饲喂轻度缺锌饲料，而C组孕期饲喂缺锌饲料、哺乳期饲唱对照饲料．断奶后（出生第20天后）仔鼠饲喂对照饲料。70日龄（P70）后分别在穿梭箱内测试备组仔鼠的学习能力。行为测试则采用条件性回避反应模型。实验结果表明，BRC组仔鼠达到学会标准所需次数分别为45．0±5．9（n＝7）和41．7±4．8（n＝12），明显多于A组（34．7±3．9，n＝11），而B组与C组间无显著性差异。行为实验结束后，在A组和B组仔鼠的海马脑片上进行了诱导长时程增强（LTP）的实验，B组脑片上诱导的LTP明显低于A组。结果提示：孕期及哺乳期锌缺乏可造成学习能力的下降，同时也影响海马的突触可塑性，而孕期可能是锌缺乏造成这种脑功能损伤的关键时期．
In the present work 30 female ICR mice and their offsprings were used and the pregnantmice were divided randomly into 3 groups: group A. as a control group. fed with control diet during pregnancyand lactation; group B fed with zinc deficient diet during pregnancy and lactation; Group C fed with zinc deficient diet during pregnancy and with control diet during lactation. The zinc contents in control and zinc-dfrlcient diet were 100 mg/kg and 5 mg/kg respectively. The offsprings from all 3 groups were fed with normaldiet after weaning (20 days old. P20). The adult offsprings (70 days old ) were used for behavioral study. Theconditioned avoidance response performed in shuttle box was used as behavioral model. The numbers of trialsneeded to reach the learning criterion for groups B and C offsprings were 45. 0±5. 9 (n=7) and 41. 7±4. 8 (n= 12) respectively. which wher much higher than that of group A offsprings (34. 7± 3. 9. n= 11). Comparingthe group A with group B. and with group C. the difference between them was very significant (P<0.01).The results showed that the learning ability of group B and C offsprings was lower than that of group A. Afterthe behavioral experiment. the induction or long-term potentiation (LTP) was investigated on the hippocampalslices of groups A and B offsprings. LTP induced in brain slices or group B offsprings was smaller than thatinduced in group A offsprings. These results indicated that zinc deficiency during pregnancy and lactationcould cause the lower learning ability and synaptic plasticity of the offsprings. Moreover. pregnancy might bethe stage of critical period for the brain function deficit of the offsprings induced by low zinc diet.
