The heavy metals, namely lead (Pb), cadmium (Cd), and mercury (Hg), have been studied extensively in various independent studies. It has been seen that these metals are usually detected simultaneously in the human blood at low levels. However, it is unknown whether exposure to these heavy metal mixtures (MM) can induce neurological damages at these low levels. Therefore, we investigated the influence of the Pb, Cd, and Hg mixture on the nervous system in rats at exposure doses equivalent to those normally found in the human blood. After pregnant rats being exposed to MM via drinking water throughout the gestation and lactation, their offspring were followed-up till adulthood. MM caused cognitive deficits and impairments in a dose-dependent manner. Furthermore, MM disrupted dendritic spines, the structural basis of learning and memory, and induced changes in spine-related pathways. Meanwhile, we explored an early and safe way to remedy these impairments through a postnatal enriched environment. The enriched environment ameliorated MM-impaired cognitive function, synaptic plasticity, and spine-related pathways. This study demonstrated that low-dose co-exposure to Pb, Cd, and Hg can cause cognitive and synaptic plasticity deficits and timely intervention through the enriched environment has a certain corrective effect.

中文翻译：

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低剂量有毒重金属混合物引起的认知缺陷的见解，以及它们在大鼠出生后丰富环境中的补救作用。

重金属，即铅（Pb），镉（Cd）和汞（Hg），已在各种独立研究中进行了广泛的研究。已经发现，这些金属通常在人血中被同时检测到低水平。然而，未知的是，暴露于这些重金属混合物（MM）能否在这些低水平下引起神经系统损害。因此，我们研究了铅，镉和汞混合物对大鼠神经系统的影响，其暴露剂量与人体血液中正常剂量相同。在整个妊娠和哺乳期，妊娠大鼠通过饮用水暴露于MM后，对其后代进行随访直至成年。MM以剂量依赖的方式引起认知缺陷和损害。此外，MM破坏了树突棘，这是学习和记忆的结构基础，并导致脊柱相关途径的改变。同时，我们探索了通过出生后丰富的环境来补救这些损害的早期安全方法。丰富的环境改善了MM受损的认知功能，突触可塑性和与脊柱相关的途径。这项研究表明，低剂量的Pb，Cd和Hg共同暴露会引起认知和突触可塑性缺陷，并且通过丰富的环境进行及时干预具有一定的矫正作用。