Female-dependent impaired fear memory of adult rats induced by maternal separation, and screening of possible related genes in the hippocampal CA1.

Early life stress is one of the major susceptible factors for stress-related pathologies like posttraumatic stress disorder (PTSD). Recent studies in rats suggest that rather than being overall unfavorable, early life stress may prepare the organism to perform optimally to stressful environments later in life. In this study, severely adverse early life stress was conducted by six consecutive hours of maternal separation (MS), from PND1 to PND21, and contextual fear conditioning model was used on PND90 to mimic the second stress in adulthood and the re-experiencing symptom of PTSD. It was observed that in this investigation pups experienced MS showed decreased sensibility to contextual fear conditioning in adulthood, and there sex plays an important role. For example, female rats suffered MS had much lower freezing than males and controls. Meanwhile, Morris water maze test indicated that MS did not impair rat's performance of spatial learning and memory. Furthermore, suppression subtractive hybridization (SSH) was used to screen the related genes of fear memory, by examining the changes of mRNA expression in CA1 area between female MS and control rats after contextual fear conditioning. Finally, nine up-regulated and one down-regulated genes, including ß2-MG, MAF, Nd1-L, TorsinA and MACF1 gene were found in this study. It is assumed that the TorsinA, MACF1 and Nd1-L gene may contribute to the decreased sensitivity of PTSD induced by MS.

[Psychological autopsy and its limitation in application].

The suicide were analyzed depending only on the death scene and cadaver features but not on the psychological autopsy (PA) that also enables the determination of the manner of death in China for a long time. There are significant differences between PA and the traditional risk assessment of suicide. The goals of PA are to find out the features of individuality, the patterns of behavior and the possible motives of suicide. The methods of PA involve investigating, collecting and analyzing all related information of the deceased. There are many limitations of PA in application mainly due to the lack of the standard procedures. Although an improved procedure has recently developed by Berman, many problems need to be solved before the actual application of PA in China.