Effects Of Chronic Unpredictable Stimuli On Depression-Like Behavior In Adolescent Cynomolgus And Preliminary Study Of The Model

Background: Studies on childhood and adolescent depression have shown the differences with adult depression in terms of pathogenesis,drug response,pathological manifestations,etc.,which urging researchers to study childhood and adolescent depression as an individual category.However,the lack of effective animal models makes the research in this field into a bottleneck.The purpose of this study was to establish a chronic unpredictable mild stimulattion depression model and advanced behavioral tests in cynomolgus monkeys and try to explore the mechanism of adolescent depression in cynomolgus monkeys.Methods: 10 adolescent cynomolgus monkeys aged 1-4 years were divided and age paired into stress group and control group.The stress group received chronic unpredictable mild stimulation intervention for 5rounds,total of 60 days.The two groups were evaluated by body weight,sucrose preference,basic behavior assessment,apple craving test,human intruder test and hair cortisol measurement,analyzed by Noldus behavior analysis software.Then Wilcoxon Matched-Pairs Signed-Ranks Test was used for statistical analysis.Results: Total reduced weights in the stress group were higher than the control group,same as the frequence of response behavior.In thehuman intruder test,the frequence of threaten face and lipsmack were higher than the control group,when duration of self groom was lower than the control group,but all the behavior data above did not show differences significantly.Sucrose preference was higher than 0.9 in both two groups,and the difference was not significant.In the stress group,the duration of huddle behavior was rised,the duration of apple craving behavior was reduced,and the hair cortisol concentration was rised,what's more was these results were statistically different.Conclusion: Cynomolgus monkeys with chronic unpredictable mild stimulation depressed performanced well in the construction validity,etiological validity,surface validity and ecological validity.Compared with the behavioral tests in previous studies,the new behavioral test in this study showed more comprehensive and effective.The cynomolgus monkey depression model and behavioral test program established in this study should have the potential to help the research on adolescent depression in the future.