| Post-traumatic stress disorder(PTSD) is a kind of trauma and stress related disorders, whose symptoms include experience, hyperarousal, avoidance, cognition and mood consistently negative change. Thereinto, hyperarousal is the core symptoms of PTSD and 5-HT is the significant neural mechanism for it to generate and develop. At present, the researchers have done a series of researches about neural mechanisms caused by hyperarousal after trauma. They found that5-HT may play a very important role in the generation of hyperarousal, but the related mechanism is not clear. We can use the animals who are lack of TPH2 damaged of 5-HT to establish a behavior genetic model of hyperarousal of PTSD, which also to investigate the effects on hyperarousal of 5-HT deficiency.We chose 123 TPH2 mice and divided them into three groups according to the grouping baseline values in the test of auditory startle reflex two days before. Depending on the type of gender and gene, they were divided into the cat stress group,the electric shock group and the control group respectively,which is to ensure that there is no difference in auditorystartle reflex among the three groups under the same condition of the gender and genotype.And then, we induced the hyperarousal behavior of those animals who were lack of TPH2 gene by cat stress or electric shock and measured their auditory startle reflex level on the first day,the second day, the tenth day and 18 thday, the immobility time in open field test on the third day and 19 thday, which is to investigate the hyperarousal.As the results showed: 1) the auditory startle reflex level of mice showed significant gender differences,the auditory startle reflex level of male mice was obviously higher than that of female mice( t( 368) = 7.780, p < 0.001). 2) the auditory startle reflex level of mice in stimulus intensity also showed significant differences(F( 2, 171) = 144.661, p < 0.001).3)the auditory startle reflex level of the stress group and control group mice showed a significant difference on the test of time.the auditory startle reflex level of the electric shock group male mice was significantly higher than that of the control group after the stress on the first day( t( 43) = 2.683,p < 0.05),second day( t( 43) = 4.018, p < 0.01) and tenth day( t( 43) = 2.778, p < 0.05); while the auditory startle reflex level of the Predatory Stress group male mice was significantly higher than that of the control group after the stress on thefirst day( t( 39) = 3.186, p < 0.01) and tenth day( t( 39)= 2.935, p < 0.05), there was no difference after the stress on thesecond day. 4) the immobility time in open field test of the stress group and control group mice showed a significant difference on the test of time. the immobility time in open field test of the electric shock group mice was significantly higher than that of the control group after the stress on the third day( t( 93) = 3.94, p < 0.001),but there was no difference between the Predatory Stress group and the control group. 5)The auditory startle reflex level of hybrid mice who lack in TPH2 gene and wild mice showed a significant difference,under the condition of the electric shock,The auditory startle reflex level of hybrid male mice was significantly higher than that of wild male mice( t( 22) = 2.462, p < 0.05), while The auditory startle reflex level of hybrid female mice was significantly higher than that of wild female mice after the stress on the second day( t( 65) = 2.474, p < 0.05).under the condition of the Predatory Stress,The auditory startle reflex level of hybrid male mice was significantly higher than that of wild male mice after the stress on the second day( t( 41) = 2.853, p< 0.01)and tenth( t( 41) = 2.570, p < 0.05)day. 6) The auditory startle reflex wake-up times of hybrid mice and wild mice showeda significant difference,under the 90 d B and electric shock condition,The auditory startle reflex wake-up times of hybrid male mice was significantly higher than that of wild male mice( t( 22) = 2.31, p < 0.05).The result showed that a behavior genetic model of hybrid male mice of PTSD was successfully established through the electric shock, in which the hyperarousal of mice was affected by gene and environment,the 5-HT deficiency would lead to a higher arousal after stress. |
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