Effect of IL-17A on lipopolysaccharide-induced neuroinflammation and fear conditioning test / 临床麻醉学杂志

ABSTRACT

Objective To investigate the effect of IL-1 7A on lipopolysaccharide (LPS)-induced neuroinflammation and fear conditioning test.Methods Among 70 male SD rats aged 18 months, firstly,thirty rats were randomly divided into five groupscontrol group(group A),LPS 6 h group (group B),12 h group(group C),24 h group(group D),48 h group(group E).Group A were injected intraperitoneally with normal saline and groups B,C,D and E were injected with LPS 500 μg/kg.Ani-mals of groups A,B,C,D and E were killed respectively after LPS injection and their hippoeampus tis-sue was detected for the concentration of IL-1 7A.Secondly,forty rats were randomly divided into 4 groupscontrol group(group O),IL-1 7A antibody group(group P),LPS group (group Q),IL-1 7A antibody+LPS group(group R).Group P and group R were injected intracerebroventricularly with IL-1 7A antibodies 3 μl (200 μg/μl),groups O and Q were injected equal volume of normal saline.30 min later,groups Q and R were injected intraperitoneally with LPS 500 μg/kg,groups O and P were in-jected equal volume of normal saline.24 h later,contextual fear conditioning test was performed. Then,all animals were killed and their hippocampus tissue would be detected for the concentration of TNF-αand IL-6,as well as the expression of Iba1-positive cells.Results The concentration of IL-1 7A of groups B,C,D and E increased significantly compared with group A (P <0.01 ),there was no difference between groups E and A.The freezing time of groups Q and R was significantly shortened than that in group O(P <0.01 or P <0.05 ),the freezing time of group R was significantly longer than that in group Q(P <0.01).The concentration of TNF-αand IL-6 of groups Q and R was obvi-ously higher than group O(P <0.01 ),the concentration of TNF-α and IL-6 of group R lower than group Q(P <0.01).The expression of Iba1-positive cells in hippocampal area CA1 of groups Q and R was obviously increased compared with group O(P <0.01).Compared with group Q,the expression of Iba1-positive cells in hippocampal area CA1 of group R were obviously decreased (P < 0.05 ). Conclusion IL-1 7A is implicated in the early stage of LPS-induced neuroinflammation and the chan-ging of freezing time in contextual fear conditioning in aged rats.