Hitomi Toshiaki, Okuda Hiroko, Takata Ayako, Yamauchi Hiroshi
Department of Preventive Medicine, St. Marianna University School of Medicine, Kawasaki, Japan.
PLoS One. 2025 Aug 25;20(8):e0330287. doi: 10.1371/journal.pone.0330287. eCollection 2025.
Coexposure to inorganic arsenic (iAs) and manganese (Mn) may exacerbate cognitive dysfunction caused by iAs alone. In this study, we investigated the cytotoxicity of coexposure to iAs and Mn in glial cells and the expression and correlation between oxidative stress and inflammatory cytokines. Additionally, we assessed tight junction (TJ) injury using a rat in vitro blood-brain barrier (BBB) model. In glial cells, coexposure to iAs and Mn increased cytotoxicity compared to single exposure, suggesting a likely additive effect. iAs exposure significantly increased the expression of antioxidant stress markers, including nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1), relative to Mn exposure. Notably, HO-1 expression was further elevated under coexposure conditions, indicating a potential synergistic effect. Regarding inflammatory cytokines, expression of C-C motif chemokine ligand 2 (MCP-1) and interleukin-6 (IL-6) was slightly higher in the iAs exposure compared to Mn exposure. A synergistic effect was observed in the Mn concentration-dependent increase in IL-6 under coexposure. A significant positive correlation was found between Nrf2 or HO-1 and inflammatory cytokines (MCP-1 and IL-6) (p < 0.001), suggesting an interaction between oxidative stress and inflammatory cytokines. The BBB TJ injury was evaluated by measuring the transendothelial electrical resistance values and the Claudin-5 and zonula occludens-1. The results showed expression in iAs exposure but not in Mn exposure. Furthermore, Mn did not affect iAs-induced TJ injury. In conclusion, our findings demonstrate that coexposure to iAs and Mn exerts synergistic effects on oxidative stress and inflammatory cytokines in glial cells. These joint effects may increase the risk of neurotoxicity compared to single-iAs or Mn exposure.
同时暴露于无机砷（iAs）和锰（Mn）可能会加剧仅由iAs引起的认知功能障碍。在本研究中，我们调查了iAs和Mn共同暴露对神经胶质细胞的细胞毒性以及氧化应激与炎性细胞因子之间的表达及相关性。此外，我们使用大鼠体外血脑屏障（BBB）模型评估了紧密连接（TJ）损伤。在神经胶质细胞中，与单独暴露相比，iAs和Mn共同暴露会增加细胞毒性，提示可能存在相加作用。与Mn暴露相比，iAs暴露显著增加了抗氧化应激标志物的表达，包括核因子红细胞2相关因子2（Nrf2）和血红素加氧酶-1（HO-1）。值得注意的是，在共同暴露条件下HO-1表达进一步升高，表明存在潜在的协同作用。关于炎性细胞因子，与Mn暴露相比，iAs暴露中C-C基序趋化因子配体2（MCP-1）和白细胞介素-6（IL-6）的表达略高。在共同暴露下观察到IL-6在Mn浓度依赖性增加方面存在协同作用。发现Nrf2或HO-1与炎性细胞因子（MCP-1和IL-6）之间存在显著正相关（p < 0.001），提示氧化应激与炎性细胞因子之间存在相互作用。通过测量跨内皮电阻值以及Claudin-5和闭合蛋白-1来评估BBB的TJ损伤。结果显示在iAs暴露中有表达而在Mn暴露中没有。此外，Mn不影响iAs诱导的TJ损伤。总之，我们的研究结果表明，iAs和Mn共同暴露对神经胶质细胞中的氧化应激和炎性细胞因子具有协同作用。与单独的iAs或Mn暴露相比，这些联合作用可能会增加神经毒性风险。
