TAK-242对脂多糖诱导的脓毒症脑病小鼠学习记忆功能障碍的改善作用

目的:探究TAK-242对脂多糖诱导的脓毒症脑病小鼠学习记忆功能障碍的改善效果,观察小鼠大脑病理学形态的改变,并探究起效的相关蛋白通路机制。方法:健康雌性C57BL/6小鼠80只,10～12月龄,体重20～30 g,采用随机数字表法分为4组(n=20):空白对照组(CON组)、TAK-242对照组(TAK组)、脓毒症脑病模型组(LPS组)和TAK-242预处理组(T+L组);取小鼠动脉血及肺脏组织检测外周炎症情况,应用旷场、高架十字和Morris水迷宫实验观察小鼠的行为学变化,后进行免疫组化实验观察海马区小胶质细胞特异性标志物离子钙结合衔接分子1(Iba-1)的形态和数量,最后通过Western blot实验检测海马区NF-κB p65、TLR4、Aβ1-42和p-tau (S396)蛋白的表达情况。结果:与CON组相比,其余各组小鼠动脉血气和肺脏组织没有出现明显炎症改变;LPS组小鼠在旷场中央区活动时间和穿过中央区次数都显著降低(P<0.01),进入高架十字开臂次数和探头区探头次数明显减少(P<0.05),水迷宫空间探索潜伏期明显延长(P<0.05),海马区Iba-1活化数目显著增加(P<0.05),NF-κB p65、TLR4、Aβ1-42和p-tau (S396)蛋白表达量明显增加(P<0.01)。与LPS组相比,T+L组小鼠在旷场中央区活动时间和穿过中央区次数显著增加(P<0.01),进入高架十字开臂次数和探头区探头次数明显增加(P<0.05),水迷宫空间探索潜伏期明显缩短(P<0.05),海马区Iba-1活化数目显著减少(P<0.05),NF-κB p65、TLR4、Aβ1-42和p-tau (S396)蛋白表达量显著降低(P<0.05)。结论:TAK-242对脓毒症脑病引起的学习记忆功能障碍具有一定的预防和治疗作用,其作用机制可能与抑制中枢小胶质细胞活化的数目及下调蛋白NF-κB p65、TLR4、Aβ1-42和p-tau (S396)的表达水平有关。

Effect of TAK-242 on learning and memory dysfunction in mice with lipopolysaccharide-induced sepsis-associated encephalopathy

AIM:To explore the effect of TAK-242 on the learning and memory ability of C57BL/6 mice with sepsis-associated encephalopathy induced by lipopolysaccharide (LPS), to observe the pathological and morphological changes of the mouse brain, and to explore the mechanism of protein pathway associated with the effect of TAK-242. METHODS:Healthy female C57BL/6 mice (n=80), aged 10~12 months, weighing 20~30 g, were randomly divided into 4 groups (n=20):blank control (CON) group, TAK-242 control (TAK) group, sepsis encephalopathy model (LPS) group and TAK-242 pretreatment (T+L) group. Peripheral inflammation in the mice was detected by testing the arterial blood and lung tissues. The behavioral changes of the mice were observed by the open-field test, elevated plus-maze test (EPMT) and Morris water maze test. Immunohistochemistry was performed to observe the changes of microglia-specific marker, ionized calcium-binding adapter molecule-1 (Iba-1), in the hippocampus. Finally, the protein expression levels of NF-κB p65, TLR4, Aβ1-42 and p-tau (S396) were determined by Western blot. RESULTS:Compared with CON group, the mice in other groups didn't showed significant difference in the arterial blood gas analysis and lung tissue HE staining. In the anxiety and fear behavior tests, central active duration and times of crossing central field of the mice in LPS group were significantly decreased compared with CON group (P<0.01). The times of open arm entry and the times of head area entry in the EPMT were significantly less than those in CON group (P<0.05). The escape latency of spatial probe experiments was significantly extended (P<0.05). Microglial activation in the hippocampus was significantly increased (P<0.05) and the protein expression levels of NF-κB p65, TLR4, Aβ1-42 and p-tau (S396) were significantly increased (P<0.01). Conversely, compared with LPS group, the central active duration and times of crossing central field in T+L group were significantly increased (P<0.01). The times of open arm entry and the times of head area entry in the EPMT were significantly increased (P<0.05). The escape latency of spatial probe experiments was significantly shortened (P<0.05). Microglial activation in the hippocampus was significantly decreased and the protein expression levels of NF-κB p65, TLR4, Aβ1-42 and p-tau (S396) were down-regulated (P<0.05). CONCLUSION:TAK-242 obviously improves the ability of learning and memory, and the mechanism may be related to the inhibition of the central microglia activation and down-regulation of protein expression levels of NF-κB p65, TLR4, Aβ1-42 and p-tau (S396).