Fkbp5 Via GR Involvement Depression-like Behavior Of Prenatally Stressed Offspring Rats

Objected: Many research showed that prenatal stress(PS)is related to psychiatric disorders,cardiovascular disorders and metabolic diseases in offspring.Our previous studies have demonstrated that PS could induce depression-like behavior in offspring.So far,the specific mechanism of PS is not clear.In recent years,many studies revealed that the number of GR and GR nuclear translocation is an important factor for the long-term hyperactivity of HPA axis,which leads to the occurrence of depression.In addition,Fkbp5 has been proved to be involved in the regulation of nuclear transfer of GR.Herein,we established a PS model to investigate the effect of PS on FK506 binding protein and GR expression.Meanwhile,we also explore the role of metformin in depression-like behavior of PS offspring.Methods: In this study,the PS model we adopted is restraint stress model.The pregnant rats were separately exposed to restraint stress on days 14–20 during pregnancy three times daily for 45 min.The control pregnant rats were left undisturbed in their home cages during the same time period.After the offspring were weaned on postnatal day(PND)21,male pups were separately housed and randomly divided into four groups.:CON group(n=8),PS group(n=8),PS-Saline group(n=8)and PS-Met group(n=8).On PND 38-39,depressionlike behavior was assessed by the sucrose preference test,forced swimming test and open filed test.Then all experimental rats were decapitated and the brain tissues were rapidly split on dry ice for further molecular analysis.The expression of GR,Fkbp5 and Fkbp4 were detected by quantitative Real-time RT-PCR and Western-blot and PS-induced methylation levels of Fkbp5 were detected by bisulfite sequencing.Result: 1.The sucrose preference test shown that the consumption of sugar solution significantly decreased in PS offspring rats when compared with control groups in the sucrose preference test.The forced swimming test revealed that the PS rats showed an increase in the immobility time in comparison with the CON group.The open filed test declared that exposed to PS remarkably decreased the number of total crossings,the number of center crossing,the number of grooming and the number of rearing in the PS group compared to the CON group.2.RT-q PCR and western-blot results showed that PS significantly reduced the total GR expression and GR nuclear translocation in hippocampus and prefrontal cortex of offspring.Meanwhile,we found it was accompanied by the augment of Fkbp5 in the hippocampus and prefrontal cortex,whereas PS have no effect on Fkbp4 expression.3.Our result revealed that intraperitoneally injected Met could reversed the downregulation of total GR expression,normalize the distribution of GR and decreased the expression of Fkbp5.However,Met have no effect on Fkbp4 expression.4.The result of BSP shown that Fkbp5 gene promoter methylation level was significantly changed in the hippocampus and prefrontal cortex of PS offspring.Interestingly,Met could reserve the level of Fkbp5 gene promoter methylation.Conclusion:In summary,our conclusion as following: GR expression and GR nuclear translocation were decreased after PS exposure.Meanwhile,Fkbp5 expression was increased of PS offspring.Met might alleviates depression-like behavior via decrease Fkbp5 methylation levels in PS offspring.