摘要目的 探讨白介素-1β (IL-1β)对脂多糖(LPS)诱导脓毒症新生幼鼠突触体相关蛋白25(SNAP-25)表达的影响.方法 SD幼鼠随机(随机数字法)分为对照组和脓毒症模型组.用1 mg/kg LPS腹腔注射SDP1 d幼鼠诱导脓毒症模型,对照组用等剂量0.01 mol/L磷酸盐缓冲液(PBS)腹腔注射.Western blot检测腹腔注射LPS 1、2和3d后海马组织IL-1β和白细胞介素1受体1(IL-1R1)的蛋白表达,7、14、28 d后海马组织SNAP-25的蛋白表达.原代海马神经元细胞培养24 h后,分为四组即对照组、IL-1β组(40 ng/mL)、IL-1β(40 ng/mL)+白介素1受体拮抗剂(IL-1Ra)(40 ng/mL)组、IL-1Ra(40 ng/mL)组,干预3d.CCK-8检测海马神经元活性,NeuN免疫荧光染色鉴定海马神经元纯度,Western blot和Real-time PCR分别检测各组SNAP-25的蛋白和mRNA水平.采用SPSS 22.0统计软件分析,数据分别采用student-t检验、Durmett-t检验以及析因设计的方差分析,以P＜0.05为差异具有统计学意义.结果 与对照组相比,腹腔注射LPS 1、2、3d后幼鼠海马组织IL-1β和IL-1R1的蛋白表达明显增加(P＜0.05);7、14、28 d后SNAP-25蛋白表达显著下降(P＜0.05).免疫荧光NeuN染色阳性细胞数约92％.用IL-1β干预海马神经元24 h后,与对照组相比SNAP-25蛋白水平降低(P＜0.05),用IL-1Ra阻断后可以逆转IL-1β诱导的SNAP-25蛋白低表达(P＜0.05),而各处理组SNAP-25的mRNA水平差异无统计学意义(P＞0.05).结论 脓毒症幼鼠海马内释放大量IL-1β可能通过其受体IL-1R1抑制神经元内SNAP-25蛋白表达,这可能是引起脓毒症幼鼠后期学习记忆障碍的重要原因.

abstractsObjective To investigate the effect of interleukin-1β (IL-1β) on the expression of synaptic protein SNAP-25 in the hippocampus in septic neonatal rat induced by systemic lipopolysaceharide (LPS) injection.Methods Sprague-Dawley (SD) rats were randomly divided into two groups:control group and sepsis group.The rat model of sepsis was produced by intraperitoneal injection of 1 mg/kg LPS,and rats in the control group were injected with an equal volume of 0.01 mol/L phosphate buffered saline (PBS).The expression levels of IL-1β and IL-1R1 in the hippocampus at 1,2 and 3 d,and synaptosomal-associated protein 25 (SNAP-25) at 7,14 and 24 d after LPS intraperitoneal injection were detected by Western blot.After cultured for 24 h,primary hippocampal neurons were divided into four groups including the control group,IL-1β (40 ng/mL) treatment group,IL-1β (40 ng/mL) + IL-1Ra (40 ng/mL) treatment group,and IL-1Ra (40 ng/mL) treatment group.The effect of IL-1β on SNAP-25 expression in primary hippocampal neuron was determined by Western blot and real-time PCR.The purity of hippocampal neurons were identified by NeuN immunofluorescence staining and the activity of neurons were detected by CCK-8 assay.All data were analyzed by SPSS version 22.0.The data were analyzed by student-t test and Dunnett-t test.The interaction effects were analyzed by factorial ANOVA.Differences were considered to be statistically significant if P＜ 0.05.Results Compared with the control group,the expressions of IL-1β and IL-1R1 were significantly increased in the hippocampus at 1,2 and 3 d after intraperitoneal injection of LPS (P＜0.05).The expression of SNAP-25 protein was decreased at 7,14,and 28 d after intraperitoneal injection of LPS (P＜0.05).The purity of primary neurons was about up to 92％.The activity of primary neurons was not relatively changed after treated with IL-1β at a dose less than 40 ng/mL.The level of SNAP-25 protein was obviously decreased in primary neurons at 24 h after IL-1β treatment (P＜0.05).IL-1Ra treatment might reverse the effect of IL-1β on primary neurons (P＜0.05).While,the expression of SNAP-25 mRNA was not statistically different in each group (P＞0.05).Conclusions IL-1β may possibly inhibit the expression level of SNAP-25 protein in the hippocampus in the septic rats through its receptor IL-1R1,which would contribute to cognitive dysfunction of septic neonatal rats in later life.