生命早期铁缺乏对CDH2基因突变大鼠神经行为学的影响

Effects of iron deficiency in early life on neuroethology in CDH2 genetic mutation rats

目的研究生命早期铁缺乏对CDH2基因突变大鼠神经行为的影响,并探讨环境因素铁营养缺乏与CDH2基因突变在孤独症样行为发生中的交互作用。方法将已建立CDH2基因点突变模型的SD雌性大鼠16只随机分为缺铁组8只和正常对照组8只。与雄性大鼠配对后,从确定怀孕起,缺铁组给予低铁饲料喂养以诱导大鼠孕期及哺乳期缺铁;正常对照组给予标准饲料喂养。子代出生后随机选取27只缺铁组仔鼠,27只对照组仔鼠,应用超声波发声实验检测仔鼠语音交流能力;应用动物行为学视频分析系统Smart3.0软件记录旷场实验、三箱社交实验的视频和数据,并统计分析相关行为学特征变化。结果子代出生后10日龄时缺铁组大鼠发声次数[(755.67±161.86)次]明显低于对照组[(1 461.89±166.57)次](P<0.05);发声持续时间[(41.77±16.17)s]明显低于对照组[(86.22±10.07)s](P<0.05)。仔鼠出生后6和8日龄时,CDH2基因突变和缺铁对大鼠发声次数的减少有协同作用(P<0.05)。缺铁组大鼠的总运行距离、在外周区域的运行距离、总平均速度、外周平均速度均大于对照组(P<0.05);此外,铁缺乏大鼠站立次数及不靠壁站立次数减少(P<0.05)。三箱社交实验第二阶段与对照组相比,缺铁组大鼠与新陌生鼠2交流时间较短,与旧陌生鼠1交流互动时间较长,表现出社交能力减弱的趋势,但差异无统计学意义(P>0.05)。结论生命早期铁缺乏与CDH2基因突变的大鼠发生了孤独症样神经行为改变,并存在一定的协同作用,可能增加了孤独症谱系障碍的发生风险。

Objective To investigate the effects of iron deficiency in early life on neurobehavioral manifestations in CDH2 genetic mutation rats,in order to explore interaction between iron deficiency and CDH2 gene mutation in autism-like behavior.Methods The 16 female SD rats with established CDH2 genetic mutations were randomly divided into 8 rats as iron deficiency group and 8 rats as normal diet control group.After mating,rats were fed low-iron diets during pregnancy and lactation or standard diets as control.The offsprings were randomly divided into 27 rats as iron deficiency group and 27 rats as control group.The voice communication ability of offspring was studied through ultrasonic vocalizations.The data and videos of open-field test,three-chamber social interaction test were recorded by animal behavioral video analysis system(Smart3.0).The characteristics of behavior changes were analyzed by statistical methods.Results Total number of calls in rats aged 10 day in iron deficiency group[(755.67±161.86)times]were significantly lower than that in the control group[(1461.89±166.57)times](P<0.05).Total calling duration[(41.77±16.17)s]were significantly lower than that in the control group[(86.22±10.07)s](P<0.05).There is a certain synergistic effect of CDH2 genetic mutation and iron deficiency on the reduction of total calls in rats aged 6 and 8 day(P<0.05).The total distance,distance in zone-periphery,mean speed in zone-total and mean speed in zone-periphery of rats in iron deficiency group were all higher than that in the control group(P<0.05);the numbers of standing and rearing were reduced(P<0.05).In the second stage of the three-chamber test,the rats in the iron deficiency group had shorter communication time with the new stranger 2 and longer interaction time with the old stranger 1 compared with the control,showing a weakening trend of social ability,but the difference was not statistically significant(P>0.05).Conclusion Autism-like behavioral changes occurred in rats with iron deficiency in early life and CDH2 genetic mutation,and there is a certain degree of synergy.Iron deficiency and CDH2 mutation may increase the risk of autism spectrum disorder.