摘要目的 观察不同孕期经历应激对成年子代大鼠情绪及认知功能的影响.方法 将12只健康清洁级Sprague Dawley (SD)雌性大鼠利用随机数字法随机分成3组:对照组(CON)、孕早期组(PS1,妊娠第1～7天)、孕晚期组(PS3,妊娠第15～21天),每组各4只.PS1、PS3组分别在妊娠第7天、第15天给予单一延长刺激(single-prolonged stress,SPS),对照组在妊娠期不给予任何处理.检测子代出生后第1～7周体质量,第8周末采用蔗糖偏好及Morris水迷宫实验分别评价其抑郁和认知功能.结果 3组子代大鼠出生后第1～7周体质量组间差异有统计学意义(F=28.207,P＜0.01),时间效应差异有统计学意义(F=1041.546,P＜0.01),孕期应激两组子代大鼠的体质量低于对照组,PS3组的体质量低于PS1组,差异有统计学意义(均P＜0.05).子代大鼠蔗糖偏爱实验:PS3组[(27.70±19.31)％]低于CON组,差异有统计学意义(P＜0.05),而PS1组蔗糖偏爱率[(89.80±6.79)％]则高于CON组[(66.93±19.67)％],差异有统计学意义(P＜0.05).子代大鼠Morris水迷宫:定位航行阶段3组大鼠逃避潜伏期差异有统计学意义(F=11.121,P＜0.01),测量时间之间差异有统计学意义(F=91.327,P＜0.01),CON组逃避潜伏期低于PS1组而高于PS3组,差异有统计学意义(均P＜0.05).探索阶段,PS3组在原平台停留时间及次数[(54.50±4.64)s,(53.21±4.45)次]高于CON组[(32.24±4.17)s,(31.68±4.00)次],差异有统计学意义(P＜0.05).结论 孕晚期应激更易引起成年子代大鼠出现抑郁样行为,学习记忆能力反而增加,而孕早期应激子代大鼠成年后学习记忆能力受损.

abstractsObjective To investigate the effect of prenatal stress (PS) at different pregnant time on emotion and cognition of adult offspring rats.Methods Twelve healthy female Sprague Dawley (SD) rats were randomly divided into control group(CON,n=4),the early pregnancy group(PS1,the 1～ 7 days of pregnancy,n=4) and the late pregnancy group(PS3,the 15 ～ 21 days of pregnancy,n=4).The pregnant rats were exposed to single-prolonged stress(SPS) on gestational day 7 or 15 respectively,except control group.The offspring were measured every weekend from 1-7 week after birth.At the eighth weekend,the sucrose intake (anhedonia) and Morris water maze (MWM) were performed to assess depression-like behavior and spatial learning and memory.Results The body weight of the first to seventh weeks after birth showed that there was a statistically significant difference among the three groups (F=28.207,P＜0.01),and there was a significant difference in time effect (F=1 041.546,P＜0.01).The body weight of two PS groups was significantly lower than those of control group(P＜0.05).The body weight of PS3 was lower than that of PS1 significantly(P＜0.05).Sucrose preference:PS3((27.70± 19.31) ％) were reductive on sucrose consumption than CON significantly((66.93±19.67) ％)(P＜0.05)while PS1 ((89.80±6.79) ％) increased in sucrose consumption compared with the CON significantly(P＜0.05).MWM:in training stage the difference of average avoid latency was existed in the three groups of the first 5 days(F=11.121,P＜0.01).Similarly,there was a significant difference in measure time(F=91.327,P＜0.01),the escape latency of the PS3 was decreased,while PS1 was significantly increased compared with CON;in testing stage,PS3 ((54.50±4.64) s,(53.21±4.45)) showed a significant increase in the duration in target site and numbers of times across the target site compared with CON((32.24±.4.17) s,(31.68±4.00)) (P＜0.05).Conclusion The acceptance of stress in the late pregnancy may lead to depression like behavior in the adult offspring and also enhance the learning and memory ability.And acceptance of stress in early pregnancy can cause impairment of learning and memory ability in adult offspring rats.