Establishment Of The Long-term Model In Mice And The Observation Of Behavior And Neuropathological Features

Objective:1.To establish the novel long-term depression model(LTD)mice,and to observe its general condition,focusing on having suicidal,self-sabotaging behaviors or not.2.Compared the LTD mice with chronic unpredictable wild stress(CUMS)mice and early life stress model(ELS)mice to observe differences in depression,anxiety and learning behaviors over time.Methods:By separating neonatal rats from their mothers,the mice were feed separately after they were weaned,giving persistent chronic stress to construct LTD mice.To establish CUMS mice by putting chronic unpredictable mild stress on the mice,and establish ELS mice by separating neonatal rats from their mothers.Comparing the differences between sucrose preference test,forced swimming test,tail suspension test,open field test,elevated plus maze test,object recognition test of these three model mice and compared the changes in hippocampal CA1,CA3,DG region neurons of eGFP transgenic LTD mice and control mice.Results:The LTD mice were successfully constructed in this experiment,which laid a guarantee for the following experiments and the research group's experiments.Compared with other depressed mice,LTD mice were more prone to self-harm behavior.Compared with CUMS and ELS mice,in LTD mice,the sugar preference index decreased significantly over a long period of time,forced swimming test and tail suspension test showed that LTD mice had prolonged resting time and were more likely to fall into the desperate situation.Meanwhile,the anxious behavior and the ability of learning and memory were not significantly affected in LTD mice compared with normal mice.And the degenerative degeneration of the hippocampal CA1 and CA3 regions of LTD mice can be observed in tissues sections.Conclusion:The LTD mice were successfully constructed,LTD mice are a model mouse which can exhibit stable depressive state.Compared with other commonly used depression model mice,LTD mice are a model mouse suitable for long-term simulation of depression,which can maintain long-term depression-like behavior and exhibit long-term psychological stress,and may cause depression-like behavior by affecting mouse hippocampal neuron survival.Meanwhile,LTD mice provide a reliable model for the research team in the subsequent study of the effects of neural stem cells and mesenchymal stem cells on depressive mice.