Effects Of Exposure To Lipopolysaccharides During Pregnancy On Age-related Anxiety-like Behaviors And Levels Of Hippocampal FABP7 Protein In F1 And F2 Offspring

Background:Anxiety disorder has a high prevalence,and the risk of anxiety increases with age.Prenatal inflammation during key developmental timepoints can result in long-term changes in anxiety phenotype,even over a lifetime and across generations.However,whether maternal inflammation exposure during late gestation has intergenerational transmission effects on age-related anxiety-like behaviors and the possible underlying mechanisms are largely unknown.Fatty acid binding protein 7（FABP7）is critical in hippocampal neurogenesis and is closely related to neuropsychiatric diseases,including anxiety disorder.The aim of this study was to investigate whether inflammatory exposure during late gestation increases age-related anxiety-like behaviors in F1 and F2 offspring and whether this intergenerational effect is related to hippocampal FABP7.Objective:To investigate the intergenerational effects of maternal（F0 generation）lipopolysaccharide administration（50μg/kg,i.p.）during late gestation on anxiety-like behaviors and FABP7 expression in F1 and F2 offspring,as well as the potential sex-specificity of intergenerational effects.Methods:During gestational day（GD）15–17,the pregnant CD-1 mice（F0）received an intraperitoneal injection of LPS（50μg/kg）or normal saline（control,CON）.The first generation（F1）,whose mothers were treated with LPS or saline,consisted of F1-LPS males（F1-LPS-M）,F1-LPS females（F1-LPS-F）,F1-CON males（F1-CON-M）,and F1-CON females（F1-CON-F;n10 per group）.F1 animals naturally mated with age-matched（2 months old）unexposed（been not descended from LPS or normal saline exposed dams）or non-littermate CD-1 mice to produce the second generation（F2）.The F2 offspring consisted of the following groups:F2-Mother-LPS₁（F2-M-LPS₁）,the offspring of F1-LPS females mated with unexposed males;F2-Father-LPS₁（F2-F-LPS₁）,the offspring of F1-LPS males mated with unexposed females;F2-Parents-LPS₂（F2-P-LPS₂）,the offspring of F1-LPS females mated with non-littermate F1-LPS males;F2-Mother-CON₁（F2-M-CON₁）,the offspring of F1-CON females mated with unexposed males;F2-Father-CON₁（F2-F-CON₁）,the offspring of F1-CON males mated with unexposed females（n=20per group,ten males and ten females）.Anxiety-like behaviors were evaluated using open field（OF）,elevated plus maze（EPM）,and black-white alley（BWA）tests in F1and F2 offspring at 3 and 13 months of age.The protein and messenger RNA levels of FABP7 in the hippocampus were measured using western blotting and real-time quantitative polymerase chain reaction,respectively.Results:（1）The effect of age:Compared to the 3-month-old CON mice,the OF peripheral time,BWA latency and the time spent in the black alley in the15-month-old CON were significantly increased（Ps<0.05）,and the squares crossed and hippocampal FABP7 protein content were significantly decreased（Ps<0.05）.（2）The effect of LPS-affected:（1）In F1 offspring,there were significant differences in the OF peripheral time,squares crossed,BWA latency,time spent in the black alley and level of FABP7 among CON and LPS mice（Ps<0.05）.Compared to the 13-month-old CON mice,the LPS had a significant increase in peripheral time,BWA latency,the time spent in the black alley（Ps<0.05）,and a significantly decrease in squares crossed and FABP7 protein expression（Ps<0.05）.（2）In F2 offspring,at the age of 13 months,there were significant differences in the OF peripheral time,squares crossed,BWA latency,time spent in the black alley and level of FABP7among M-LPS₁,F-LPS₁,P-LPS₂,M-CON₁and F-CON₁（Ps<0.05）.Compare to the other four groups,the M-LPS₁females was the highest in the peripheral time（Ps<0.05）,while the squares crossed and FABP7 protein expression were the lowest（Ps<0.05）.The OF peripheral time,BWA latency and the time spent in the black alley in the M-LPS₁,F-LPS₁were significantly longer than the M-CON₁and F-CON₁（Ps<0.05）.But the squares crossed and FABP7 expression in the M-LPS₁,F-LPS₁were significantly lower than M-CON₁and F-CON₁（Ps<0.05）.（3）FABP7 and anxiety-like behaviors:The hippocampal FABP7 protein in the 3-month-old F1 and F2 mice,as well as 13-month-old F1 and F2 mice were negatively correlated with the peripheral time and positively correlated with the squares crossed.The hippocampal FABP7 protein in the 3-mouth-old F1 and F2 mice and the 15-mouth-old F1 and F2 mice were negatively correlated with the BWA latency and the time spent in the black alley（Ps<0.05）.Conclusions:Overall,gestational LPS exposure in the F0 generation increased age-related anxiety levels and decreased hippocampal FABP7 expression levels in the F1 generation,which carried over to the F2 generation,and the intergenerational effects were mainly transferred via the maternal lineage.Moreover,hippocampal FABP7 expression was significantly correlated with performance in the battery of anxiety tests.The present study suggested that prenatal inflammation could increase age-related anxiety-like behaviors both in F1 and F2 offspring,and these effects possibly link to the FABP7 expression.