机场噪声对小鼠认知功能及肠道菌群的影响

目的 研究慢性机场噪声暴露对小鼠认知功能及肠道菌群的影响,探讨肠道菌群变化是否介导噪声导致的认知功能下降,为长期飞机噪声暴露人群预防认知功能下降提供科学依据。方法 30只5周龄c57bl/6j小鼠随机分为对照组和噪声暴露组,每组15只,噪声暴露组在最大声压级85 dB,等效连续声压级69 dB的飞机噪声中暴露100 d,对照组置于背景噪声<50 dB的饲养室中。噪声暴露结束后,通过Morris水迷宫实验和旷场实验检测小鼠认知功能水平,16s r DNA测序分析肠道菌群变化,靶向代谢组学测定血清短链脂肪酸（short-chain fatty acids, SCFAs）（包括乙酸,丙酸,丁酸）水平,通过qPCR检测小鼠结肠组织闭合蛋白（CLDN-1）,咬合蛋白（Occludin）和闭合小环蛋白（ZO-1）以及脑组织肿瘤坏死因子（tumor necrosis factor-α, TNF-α）、白介素-6(interleukin-6, IL-6)、白介素-10(interleukin-10, IL-10)mRNA表达水平。结果 两组小鼠的平均逃避潜伏期均呈下降趋势,机场噪声暴露组的逃避潜...

Effects of airport noise on cognitive function and intestinal flora in mice

Objective To investigate the effects of chronic airport noise exposure on the cognitive function and intestinal microflora in mice, and to explore whether the changes of intestinal flora mediate the decline of cognitive function caused by noise, so as to provide scientific basis for preventing cognitive decline in people exposed to long-term aircraft noise. Methods Thirty 5-week-old c57bl/6j mice were randomly divided into control group (n=15) and noise exposure group (n=15). The noise exposure group was exposed to aircraft noise with maximum sound pressure level (85dB) and equivalent continuous sound pressure level (69dB) for 100 days, and the control group was placed in a feeding room with background noise < 50dB. After noise exposure, the cognitive function of mice was detected by Morris’s water maze test and open field test, the changes of intestinal flora were analyzed by 16srDNA sequencing, the levels of serum short chain fatty acids (SCFAs) including acetic acid, propionic acid, and butyric acid were determined by targeted metabolomics, and the colonic tissue closure protein (CLDN-1), the mRNA expression levels of occlusal protein (Occludin), and closed small cycle protein (ZO-1) as well as tumor necrosis factor α (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL10) in brain tissue were detected by qPCR. Results The average escape latency of mice in both groups showed a downward trend. The average escape latency in the airport noise exposure group was significantly longer than that in the control group (31.65 ±11.11) vs. (15.86±3.47) (t=3.32, P<0.05). After the platform was removed, the number of times of crossing the platform in the noise group was fewer than that in the control group [(2.33±1.03) vs.(5.43 ±2.15), t=3.21, P<0.05], and the stay time in the target quadrant was shorter [(28.74±4.24) vs. (36.72±5.65), t=2.84, P<0.05]. In the open field experiment, the total movement distance [(2 342.44±434.76) vs. (2 962.31±350.21), t=2.72] and the movement distance in the central area [(33.18 ±8.98) vs. (73.61 ±32.80), t=2.91] in the noise exposure group were shorter than those in the control group (P<0.05), and the stay time in the central area was shorter than that in the control group [(1.69±0.86) vs.(3.12±0.86), t=2.89, P<0.05]. The intestinal flora of mice was disordered, the short chain fatty acid producing bacteria decreased, the contents of serum acetic acid [(0.27±0.34vs.1.18 ±0.54, t=3.21], propionic acid [(0.24 ±0.07) vs. (0.45±1.15), t=2.84] and butyric acid [(0.05±0.02) vs. (0.08±0.02), t=2.43] decreased significantly (P<0.05). The intestinal epithelial barrier was damaged and the expression levels of CLDN-1, Occludin, and ZO-1mRNA were significantly decreased. The level of pro-inflammatory factor TNF- α increased and the level of anti-inflammatory factor IL-10 decreased in brain tissue. Conclusion Chronic airport noise exposure leads to the decrease of learning and memory ability, cognitive impairment, disorder of intestinal flora structure, change of intestinal flora metabolite level, increase of intestinal epithelial permeability, and inflammation level of brain tissue.