其他摘要 | Objectives: According to a recent epidemiological survey, 29.2% and 54.7% of adolescents who had PTSD or suffered from PTSD during their lifetime also had depression, ranking first in the co-morbidity rate of PTSD and other psychological disorders. At present, one of the views on the causes of co-morbidity, "the level of depression before stress is a risk factor for the emergence of PTSD symptoms after stress",has made some progress, but it is not yet supported by evidence from experimental animal studies. In addition, clinical studies have revealed individual differences in symptom phenotypes and developmental trajectories of the two co-morbidities. Currently, there is a lack of research on the individual differences between the two co-morbidities. NPY is known to be strongly associated with individual differences in PTSD and depression; however, whether NPY Y2R receptors are involved in regulating PTSD and depression co-morbidity is unclear. The aim of this study was to investigate the relationship between adolescent depression levels and the behavior of rats with PTSD models, NPY Y2R, and to provide evidence for the prediagnosis of adolescent PTSD and depressed individuals as well as for prognostic treatment.
Methods: A single prolonged stress model in rats was used to induce PTSD in adolescent rats. A combination of meta-analysis, animal behavioural and Western Blot and qRT-PCR methods was used to explore the correlation of depression levels in adolescence with the behavior of rats in a model of post-traumatic stress disorder and the NPY Y2R.
Results:Study 1 is a review meta-analysis, the first meta-analysis for the effect of single prolonged stress model on depression-like behavior in animals, extracting the results of five databases of existing experimental studies exploring single prolonged stress model and depression-like behavior in rodents, which found that single prolonged stress could well induce depression-like behavior in animals; the results of the heterogeneity test showed individual differences in depression-like behavior in animals induced by the single prolonged stress model, and it was determined that the depression-like behavior of animals in the single prolonged stress model was measured using the sucrose preference test. Study 2 distinguished the psychologically vulnerable group, the psychologically resilient group and the control group according to the pre-stress sucrose preference level, and observed the effects of PTSD modeling on depression-like behaviors, spatial cognitive ability and non-spatial cognitive ability in the three groups of animals, and found that (1)there were no significant differences in desperate behaviors (immobility time) in the forced swim test between the psychologically vulnerable and psychologically resilient groups during single prolonged stress. After single prolonged stress, there was no significant difference in the level of sucrose preference among the three groups of rats; compared with pre-stress, the sucrose preference values increased significantly in the control group and did not change significantly in the stress group. The three groups did not differ significantly in anxiety一like behavior in the elevated plus maze after stress. (2) There was no significant effect of adolescent single prolonged stress on the non-spatial cognitive ability of rats, and there was no significant difference in the novel object recognition index of the three groups, but in the spatial cognitive ability water maze test, the learning task of finding the survival platform for the 5th to 8th times, the time to find the escape platform was significantly longer in the psychologically vulnerable rats than in the control and the time spent in the target quadrant was significantly lower in the psychologically resilient group than in the control rats during the memory test phase. Study 3 used Western Blot and qRT-PCR to analyze the expression level of hippocampal NPY Y2R in adolescent rats, and found that single prolonged stress in adolescence was found to have a significant effect on protein expression rather than mRNA expression levels of NPY Y2R in the rat hippocampus, as shown by the protein expression level of hippocampal NPY Y2R in rats in the psychologically vulnerable group was significantly reduced, and further correlation analysis showed that changes in the time of staying in the escape platform of the water maze in rats were significantly and positively correlated with the hippocampal NPY Y2R protein expression.
Conclusions:Based on the above results, the level of adolescent depression affects the spatial learning ability of rats in the psychologically vulnerable group and the spatial memory ability of rats in the psychologically resilient group after post-traumatic stress disorder modeling, which may be mediated by protein expression of NPY Y2R receptors in hippocampal region. |
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