噪声暴露通过IL-6调控APOE表达诱导小鼠海马神经元损伤及认知功能障碍

Noise exposure induces hippocampal neuronal damage and cognitive dysfunction in mice via Il-6-mediated APOE upregulation

摘要

目的 探究IL-6分泌调控载脂蛋白E(APOE)的表达在噪声暴露诱导小鼠认知障碍中的潜在影响,并阐明其可能的机制。方法 将5月龄C57BL/6J小鼠随机分为对照组(NN-C57)和噪声暴露组(NE-C57)。构建噪声暴露模型后,通过旷场、新物体识别及水迷宫等行为学测试评估小鼠的学习与空间记忆能力;HE染色观察小鼠海马区的形态变化;Nissl染色观察神经元的损伤;免疫荧光和Western blot(WB)技术检测小鼠海马区IL-6与APOE的表达变化,并分析炎症因子及IL-6相关通路蛋白的表达变化。细胞实验取对数生长期的HT22细胞,随机分为对照组和IL-6组。WB检测IL-6与APOE的蛋白水平,验证IL-6调控APOE的相关通路(ERK1/2-SP1)的影响。结果 动物实验:与对照组相比,噪声暴露组小鼠的学习与空间记忆能力下降,IL-6炎症因子水平上升,APOE表达也显著增多;同时相关通路蛋白ERK1/2磷酸化增强,转录因子SP1表达增加。细胞实验:与对照组相比,IL-6干预组APOE蛋白的表达水平均显著增加;同时发现,IL-6刺激处理后细胞关键激酶P-ERK1/2上调,必需转录因子SP1蛋白增加。结论 噪声暴露通过促进IL-6分泌调控APOE表达,从而引起神经元损伤导致小鼠的认知功能障碍。

Abstract

Objective To investigate the potential impact of IL-6 secretion-regulated apolipoprotein E (APOE) on noise exposure-induced cognitive impairment in mice and clarify its possible mechanism. Methods Five-month-old male C57BL/6J mice were randomly divided into the control (NN-C57) group and the noise exposure (NE-C57) group. Noise exposure model was constructed, a series of behavioral tests including the open field test, novel object recognition test, and water maze test were carried out to assess the cognitive and spatial memory capabilities of the mice.The morphological changes of the hippocampus were observed by Hematoxylin and Eosin (HE) staining technique, and the neuronal impairment was scrutinized by NISSL staining. Furthermore, immunofluorescence and Western blot (WB) were used to detect the expression of IL-6 and the Apolipoprotein E (APOE) gene in the hippocampus, and the alterations in the expression of inflammatory factors and IL-6-related pathway proteins were analyzed. HT22 cells in the exponential growth phase were assigned to Control and IL-6 group. Western blot (WB) analysis was conducted to quantify the expression levels of IL-6 and APOE proteins, to verify the influence of IL-6 on the related pathways (ERK1/2-SP1) on APOE. Results Animal experiments: Compared with the control group, mice in the noise exposure group exhibit significant declines in learning and spatial memory abilities, along with the elevated levels of IL-6 inflammatory factor markedly increased APOE expression. The phosphorylation of the related pathway protein ERK1/2 is enhanced, and the expression of the transcription factor SP1 increases. Cellular experiments: Compared with the control group, the expression levels of APOE proteins in the IL-6 group are significantly enhanced. At the same time, it finds that after IL-6 stimulation treatment, the key kinase P-ERK1/2 in the cells is upregulated, and the protein of the essential transcription factor SP1 increases. Conclusion Noise exposure regulates the expression of APOE by promoting the secretion of IL-6, thereby causing neuronal damage and resulting in cognitive dysfunction in mice.

关键词

噪声暴露 / 白细胞介素-6 (IL-6) / 载脂蛋白E(APOE) / 海马 / 神经元损伤 / 认知功能障碍

Key words

noise exposure / interleukin-6 (IL-6) / apolipoprotein E (APOE) / hippocampus / neuronal damage / cognitive dysfunction

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基金资助

浙江省自然科学基金项目(LMS25H130002)