Anti-miR-142 Alleviates PTSD-like Behaviors Through Upregulating The Expression Of FMRP,Reducing Proinflammatory Cytokines And Apoptosis In The Hippocampus Of PTSD Rats

Object: To study the possible molecular mechanism of inhibiting micro RNA-142(miR-142)in alleviating the behavioral abnormalities of post-traumatic stress disorder(PTSD)model rats.Methods:(1)Forty-eight male Sprague-Dawley rats were randomly divided into four groups.The experimental groups were treated with the single-prolonged stress(SPS)procedure and injected with a lentivirus-mediated inhibitor of miR-142-5p.(2)Different behavioral tests were used to evaluate the effect of antisense miR-142-5p on the PTSD-like behaviors including depressive-like behavior,anxiety-like behavior and memory abnormality in rats of each group.(3)The expression levels of FMRP、PSD95、Synapsin I、IL-1β、IL-10、TNF-α and NF-κB p65 in the rat hippocampus were tested by immunofluorescence staining and Western blot.(4)The levels of IL-1β、IL-6and IL-10 in the rat hippocampus were measured by ELISA and Western blot.(5)The apoptosis level in the hippocampus was evaluated by flow cytometry assay,and the expression levels of bax、bcl-2 and caspase-3 in the rat hippocampus was evaluated by Western blot.(6)Rat microglia cells were stimulated by lipopolysaccharide(LPS),and the neurons were cultured in the conditioned medium collected from microglia cells treated with LPS.The morphological changes of dendritic spines in the neurons of each group were detected by immunofluorescence staining.(7)The expression level of FMRP in neuron-like cells induced from PC12 cells,transfected with miR-142,was evaluated by Western blot.The expression level of NF-κB p65 in neuron-like cells induced from PC12 cells,transfected with FMR1 or sh-FMR1 was also tested by Western blot.(8)The binding ability of miR-142 and FMRP was detected by Luciferase reporter assay.Results:(1)Anti-miR-142 could significantly alleviate depression-like behaviors,anxiety-like behaviors and memory impairment in PTSD rats;(2)Compared with Control group,the expression level of PSD95 and Synapsin I in the hippocampus of rats in PTSD group was reduced,and the injection of anti-miR-142 significantly reversed this trend;(3)The level of neuronal apoptosis in the hippocampus of PTSD rats was significantly higher than that of in Control group,and the injection of anti-miR-142 significantly reversed this trend;(4)Compared with the Control group,the expression levels of Iba-1 、 NF-κB p65 、 IL-1β 、 IL-6 and TNF-α in the hippocampus of PTSD rats were increased,and the injection of anti-miR-142 significantly reversed this trend;(5)Compared with the CM group,the total number of spine and the ratio of mature dendritic spine in the L-CM group were reduced significantly,and the transfection of anti-miR-142 could significantly reverse this trend;(6)The expression level of FMRP in the hippocampus of PTSD rats or neuron-like cells in L-CM group were reduced and the expression level of NF-κB p65 in nuclei was significantly increased,the downregulation of miR-142 significantly reversed these trends;(7)FMRP was a direct target of miR-142 tested through luciferase reporter assay.Conclusions: Downregulation of miR-142 could significantly alleviate depression-like behaviors,anxiety-like behaviors and memory abnormalities in PTSD rats through upregulating the level of FMRP and reducing the level of pro-inflammatory factors and cell apoptosis in the hippocampus.