不同声强8Hz次声对小鼠学习能力的影响

目的：观察不同声强的８Ｈｚ次声长时间作用后小鼠学习能力的变化并探索其作用机理．方法：学习能力相近的ＢＡＬＢ／ｃ小鼠５０只，随机分５组，除对照组外分别接受９０ｄＢ、１００ｄＢ、１１０ｄＢ、１２０ｄＢ８Ｈｚ次声的作用，每日３ｈ，１４ｄ后用Ｙ－型电迷宫进行学习能力的比较、脑皮质超微结构的电镜观察和脑生化物质的１Ｈ－核磁波谱分析．结果：实验组学习能力均较对照组降低（Ｐ＜０．０５或Ｐ＜０．０１）；电镜观察脑皮质神经细胞出现脂褐素增多及线粒体肿胀．１Ｈ－核磁波谱分析发现乙酰门冬氨酸（ＮＡＡ）、胆碱（Ｃｈｏ）、谷氨酸（Ｇｌｕ）等相对含量显著变化（Ｐ＜０．０１）．结论：９０ｄＢ次声长时间作用即可引起学习能力降低，其原因与次声致使脂质过氧化有关．在９０ｄＢ组和１００ｄＢ组，神经细胞对次声的损害存在代偿反应．

Effects of 8 Hz infrasound with different intensity on learning capacity of mice

Objective: To explore the mechanism of the effects of infrasound with different intensity on the learning capacity of mice. Methods: Fifty BALB/c mice, with equal learning capacity, were divided into 5 groups. Except the control, the exposed groups were exposed to infrasound of 8 Hz with different intensity 3 hours a day. After 14 days, we compared every group's learning capacity by Y pattern electric maze, observed the ultrastructure change of brain cortex by electron microscope, and analyzed the relative content of some biochemical substance by 1H NMR spectroscoper. Results: The learning capacity of all exposed groups was obviously lower than that of control ( P <0.05 or P <0.01). The ultrastructure change showed that lipofuscin distributed in cytoplasma of 90 dB and 100 dB groups, mitochondria swelled in other groups. 1H NMR spectroscoper demonstrated that the relative content of N actyl l asprtic acid (NAA), choline (Cho), glutamic acid (Glu) significantly changed ( P <0.01). Conclusion: Long time exposure to 8 Hz infrasound with 90 dB intensity might impair learning capacity of mice, which might be connected with lipid peroxidation caused by infrasound. In 90 dB and 100 dB groups, neurocytes can compensate for the damage of infrasound by themselves.