IL-17A对脂多糖致老年大鼠早期中枢炎症和场景性恐惧实验的作用

目的探讨IL-17A对脂多糖(LPS)致老年大鼠早期中枢炎症和恐惧实验的影响。方法雄性SD大鼠70只,18月龄,首先取30只大鼠随机均分为五组:腹腔注射生理盐水(生理盐水组,A组)、腹腔注射LPS 500μg/kg 6h组(B组)、12h组(C组)、24h组(D组)、48h组(E组)。检测LPS注射后各组大鼠海马IL-17A的表达。随后,将剩余40只大鼠随机均分为四组:空白对照组(O组)、IL-17A抗体组(P组)、LPS腹腔注射组(Q组)、IL-17A抗体+LPS腹腔注射组(R组)。P组和R组大鼠侧脑室给予IL-17A抗体3μl(200μg/μl),O组和Q组给予同体积生理盐水;30min后,Q组和R组大鼠腹腔注射LPS(500μg/kg),O组和P组给予同体积生理盐水,24h后各组行场景性恐惧实验,记录四组大鼠的僵直时间,检测海马TNF-α和IL-6水平及CA1区Iba1阳性细胞的表达。结果 B、C和D组大鼠海马中IL-17A的表达明显高于A组(P0.01),E与A组IL-17A的表达差异无统计学意义;Q组和R组大鼠僵直反应时间明显短于O组(P0.05或P0.01),R组大鼠僵直反应时间明显长于Q组(P0.01);Q组和R组大鼠海马TNF-α和IL-6的水平明显高于O组(P0.01),R组大鼠海马TNF-α和IL-6水平明显低于Q组(P0.01);Q组和R组大鼠海马CA1区Iba1阳性细胞数目明显多于O组,R组大鼠海马CA1区Iba1阳性细胞数目明显少于Q组(P0.05)。结论 IL-17A参与LPS引起的老年大鼠早期中枢炎症因子TNF-α和IL-6的表达、小胶质细胞的活化以及场景性恐惧实验的僵直时间改变。

Effect of IL-17A on lipopolysaccharide-induced neuroinflammation and fear conditioning test

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 groups:control 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 groups:control 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.