丙酮酸乙酯对盲肠结扎穿孔法致脓毒症大鼠模型学习记忆能力及海马HMGB1表达的影响

Effects of ethyl pyruvate on learning and memory ability of CLP-induced sepsis rats and HMGB1 expression in hippocampus

目的分析丙酮酸乙酯(EP)对盲肠结扎穿孔法(CLP)致脓毒症大鼠模型学习记忆能力及海马高迁移率运动蛋白族1(HMGB1)表达的影响。方法取40只SD大鼠,脓毒症大鼠模型的构建采用CLP法,随机分为假手术组(开腹,但不结扎穿孔)、脓毒症组(建立脓毒症大鼠模型)、假手术+HMGB1组(在假手术组基础上应用HMGB1)、脓毒症+HMGB1组(在模型组基础上应用HMGB1)、脓毒症+EP组(在模型组基础上应用EP),每组均为8只。检测各组大鼠学习记忆能力,取大鼠脑组织标本,行尼氏染色以观察海马区神经元形态学改变,并通过实时荧光定量聚合酶链式反应检测大鼠海马区HMGB1 mRNA的相对表达量。结果相比假手术组,脓毒症组、假手术+HMGB1组、脓毒症+HMGB1组及脓毒症+EP组逃避潜伏期延长,游泳距离增加(P<0.05);相比脓毒症组,脓毒症+HMGB1组逃避潜伏期延长(P<0.05),脓毒症+EP组逃避潜伏期和游泳距离均缩短(P<0.05)。尼氏染色结果可见假手术组海马区CA1区神经元细胞排列紧密整齐,轮廓清晰可见;其余四组神经元细胞数量较少,局部结构不清,细胞体皱缩肿胀、深染。相比假手术组,脓毒症组、假手术+HMGB1组、脓毒症+HMGB1组及脓毒症+EP组HMGB1 mRNA相对表达量均明显升高(P<0.05);相比脓毒症组,脓毒症+HMGB1组HMGB1 mRNA的表达明显升高(P<0.05),假手术+HMGB1组、脓毒症+EP组HMGB1 mRNA的表达明显下降(P<0.05),且脓毒症+EP组更为显著。结论EP可有效减轻脓毒症引起的认知功能损害,其作用机制可能与缓解机体炎症反应,改善血脑屏障功能密切相关。

Objective To analyze the effect of ethyl pyruvate(EP)on learning and memory ability of sepsis rat model induced by cecal ligation and puncture(CLP)and the expression of high-mobility group box-1(HMGB1)in hippocampus.Methods 40 SD rats were randomly divided into sham operation group(open but without ligation and perforation),sepsis group(establishment of sepsis rat model),sham operation+HMGB1 group(application of HMGB1 on the basis of sham operation group),sepsis+HMGB1 group(application of HMGB1 on the basis of model group),sepsis+EP group(application of EP on the basis of model group),with 8 rats in each group.The learning and memory abilities of rats in each group were tested.Brain tissue samples were taken and Nissl stained to observe the morphological changes of neurons in hippocampus.The relative expression of HMGB1 in hippocampus was detected by real-time fluorescence quantitative polymerase chain reaction.Results Compared with sham operation group,escape latency and swimming distance of sepsis group,sham operation+HMGB1 group,sepsis+HMGB1 group and sepsis+EP group prolonged and increased(P<0.05).Compared with sepsis group,escape latency of sepsis+HMGB1 group prolonged and increased(P<0.05),while escape latency and swimming distance of sepsis+EP group shortened(P<0.05).The results of Nissl staining showed that neurons in hippocampal CA1 area of sham-operated group were arranged tightly and neatly with clear outline.The other four groups had fewer neurons,unclear local structure,and their bodies shrunken,swollen and deeply stained.Compared with sham operation group,the relative expression of HMGB1 in sepsis group,sham operation+HMGB1 group,sepsis+HMGB1 group and sepsis+EP group increased significantly(P<0.05).Compared with sepsis group,the expression of HMGB1 in sepsis+HMGB1 group increased significantly(P<0.05).The expression of HMGB1 in sham operation+HMGB1 group,sepsis+EP group decreased significantly(P<0.05),and the expression of HMGB1 in sepsis+EP group was more significant(P<0.05).Conclusion EP can effectively alleviate cognitive impairment caused by sepsis,and its mechanism may be closely related to alleviating inflammation and improving blood-brain barrier function.