孕期和哺乳期轻度缺锌对仔鼠学习记忆能力的影响

Effect of mild zinc deficiency during pregnancy and lactation on learning and memory in offspring rats

目的探讨孕期和哺乳期母鼠缺锌对仔鼠幼年期学习记忆能力的影响。方法怀孕1 d的孕鼠随机分为轻度缺锌组和对照组,每组3只。缺锌饲料、正常饲料含锌量分别为5 mg/kg、25 mg/kg。产后每窝随机保留4只。至21 d断乳去母鼠,每组12只仔鼠,继续饲以缺锌和正常饲料,分别于28 d及58 d以Morris水迷宫测试仔鼠的短期及长期学习记忆能力。结果学习获得实验(短期记忆)及记忆保持实验(长期记忆):对照组定位能力较好,游泳轨迹以目标象限为主;而缺锌组定位能力较差,游泳轨迹比较分散;缺锌组仔鼠找到平台的潜伏期、总游程大于对照组(P<0.01);两组游速的差异无统计学意义(P>0.05)。随着训练天数的增加,对照组上述各项记录都随着训练天数增加而变化,其中潜伏期和总游程随着训练天数增加而逐步减少,游泳速度、目标象限游程占总游程的百分比随着训练天数的增加而增加,缺锌组的变化趋势不如对照组明显。结论孕期及哺乳期母鼠轻度缺锌影响仔代生长期幼鼠短期与长期学习记忆能力。

Objective To investigate the effect of mild zinc deficiency during pregnancy and lactation on learning and memory in offspring rats.Methods Pregnant SD rats were randomly divided into two groups on first day,mild zinc deficiency group and control group.Mild zinc deficiency group fed with mild zinc deficiency diet（zinc content 5 mg/kg）,and control group fed with control diet（zinc content 25 mg/kg）during pregnancy and lactation.Each group had 3 pregnant rats.After parturition,4 offspring rats with similar weigh were kept in each brood,so each group had 12 offspring rats.After weaning,the offspring rats continued feeding mild zinc deficient diet and control diet.At the age of 28 days and 58 days offspring rats had been tested with,behavioral trials including place navigation（short-term memory）and retention place navigation（long-term memory）,with Morris Water maze test.Results Both short-term and long-term memory trials showed that the control group had a better orientation ability than the zinc deficiency group.The control group limited swim traces mainly in the target quadrant,while the zinc deficiency group distracted.The zinc deficiency group spent more time in finding the latent platform（escape latency）and swam longer distance（P 0.01）.The swimming speed between two groups was no significantly different（P 0.05）.In control group,with the increase of training days,both the escape latency and total swimming distance were reduced gradually,while the swimming speed and the orientation ability were improved.However,the same tendency in zinc deficiency group was slower than the control group.Conclusions Mild zinc deficiency during pregnancy and lactation results in the impairment of both short-term and long-term memory in offspring.