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Objective PTSD (Posttraumatic Stress Disorder, PTSD) there are more risk factors, including gender, age, race, genetic factors, parental history of PTSD and early adverse experiences, etc., poor early life stress as an important and easy a sense of one of the factors, gradually attracted everyone's attention. This study of early life stress caused by environmental factors adverse changes in gene expression for children at risk populations, prevention and treatment of PTSD find effective drugs and psychological intervention targets, has important significance. Therefore, the subject of maternal separation using animal models and animal models and scenes of fear memory suppression subtractive hybridization method to study early life stress induced adverse adult susceptibility to changes related fear memory differentially expressed genes and analyzed differentially expressed genes in Yi the possible role of perceptual mechanisms, explore maternal separation on adult fear memory formation and maintenance of susceptibility. Methods Part I: 1, animal models of maternal separation: 1-21 days after birth, pups, all pups brought out into another cage, 6h after the return of newborn pups get reunited with maternal birth After the first 21 days 6 per cage rearing. Normal control rats on normal feeding after birth, not with maternal separation. 21 days after weaning, six per cage rearing. 2, Scene animal models of fear memory: Training: The rats were gently placed in the test rats in a cage, allowed freedom of movement 180 seconds, and then give two seconds rat foot shock (unconditioned stimulus, US), 0.8mA, total of three times, each time interval of 60 seconds. After training, the rats continued to stay in the training box for 60 seconds and then return it to the cages. After training, one hour and 24 hours, respectively Scene fear memory retention test. 3, spatial learning and memory tests: the first 4 days for the training phase, training four times a day, the rats were randomly oriented wall into the pool from any quadrant, and record the time in rats find the hidden platform (escape latency) as well as on site before journey to find the platform to allow animals to stay on the platform 30s; rats in the 90s if not found within the platform, denoted 90s. 4 times a day the average score for the day results. 5 days, rut addition site, and the rats were recorded swimming trajectory in the 90s, the target quadrant were calculated across the swimming time and distance the percentage of the total swimming time. Part II: Application of suppression subtractive hybridization (Suppression subtractive hybridization, SSH) screening group and the normal composition of maternal separation in rats after scene of fear memory differentially expressed genes, the obtained sequence homology. Results Behavioral results: female rats prior to maternal separation in the shock group scenes get stronger fear memory in the normal group, electric shock, the maternal separation group scenes of fear memory acquisition weaker than the normal group. The male rats in shock scenarios before and after the shock of fear memory was no significant difference obtained. Scene fear memory retention, 1h after the short-term memory test, female rats maternal separation group stiffness was significantly lower than normal group (P lt; 0.01); maternal separation group of male rats stiff time difference compared with the normal group not statistically significant (P = 0.673). Meanwhile Maternal Separation on adult scenes of fear memory retention gender differences, maternal separation group was significantly lower than in female rats stiff male rats (P lt; 0.01) 24h long-term memory test, in fear memory training, female stiff rat maternal separation group was significantly lower than the normal group (P lt; 0.01); stiff male rat maternal separation group compared with the normal group time difference was not statistically significant (P = 0.093). Meanwhile Maternal Separation on adult sex scene fear memory retention gender differences, maternal separation group was significantly lower than in female rats stiff male rats (P lt; 0.01) spatial learning and memory test results: female female and male rats infant separation group latency, and the corresponding distance on the stage compared to the control group showed no significant difference; experiments in space exploration, female, male rats maternal separation group, the percentage of the target quadrant dwell time, the percentage of the target quadrant distance were compared with the control group showed no significant difference. 2, SSH Results: 9 regulated genes, of which 5 is a partial sequence of known genes, a new EST sequences, the expression of this gene was obtained on the basis of maternal separation. Conclusions Maternal Separation scenes of female rats can reduce fear memory retention, may be due to female rats during stress in the face of higher corticosterone secretion, enhance the feedback inhibition of the HPA axis. And maternal separation can affect the expression of certain genes, and the expression levels of these genes may be related to changes in adult female rats reduced susceptibility scene of fear memory related.
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