Department of Pathobiology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Mizohoku Tanabedori, Nagoya, Aichi, 467-8603, Japan.
Department of Perinatal and Neonatal Medicine, Aichi Medical University, 1-1 Yazako, Karimata, Nagakute, Aichi, 480-1195, Japan.
Cell Mol Neurobiol. 2021 Apr;41(3):459-468. doi: 10.1007/s10571-020-00860-z. Epub 2020 May 7.
Although therapeutic hypothermia (TH) provides neuroprotection, the cellular mechanism underlying the neuroprotective effect of TH has not yet been fully elucidated. In the present study, we investigated the effect of TH on microglial activation to determine whether hypothermia attenuates neuronal damage via microglial activation. After lipopolysaccharide (LPS) stimulation, BV-2 microglia cells were cultured under normothermic (37 °C) or hypothermic (33.5 °C) conditions. Under hypothermic conditions, expression of pro-inflammatory cytokines and inducible nitric oxide synthase (iNOS) was suppressed. In addition, phagocytosis of latex beads was significantly suppressed in BV-2 cells under hypothermic conditions. Moreover, nuclear factor-κB signaling was inhibited under hypothermic conditions. Finally, neuronal damage was attenuated following LPS stimulation in neurons co-cultured with BV-2 cells under hypothermic conditions. In conclusion, hypothermia attenuates neuronal damage via inhibition of microglial activation, including microglial iNOS and pro-inflammatory cytokine expression and phagocytic activity. Investigating the mechanism of microglial activation regulation under hypothermic conditions could contribute to the development of novel neuroprotective therapies.
虽然治疗性低温（therapeutic hypothermia，TH）可提供神经保护作用，但 TH 发挥神经保护作用的细胞机制尚未完全阐明。本研究旨在探讨 TH 对小胶质细胞激活的影响，以确定低温是否通过小胶质细胞激活来减轻神经元损伤。在脂多糖（lipopolysaccharide，LPS）刺激后，将 BV-2 小胶质细胞在常温（37°C）或低温（33.5°C）条件下进行培养。在低温条件下，促炎细胞因子和诱导型一氧化氮合酶（inducible nitric oxide synthase，iNOS）的表达受到抑制。此外，低温条件下，BV-2 细胞对乳胶珠的吞噬作用明显受到抑制。此外，低温条件下核因子-κB 信号通路受到抑制。最后，在低温条件下与 BV-2 细胞共培养的神经元中，LPS 刺激后神经元损伤减轻。总之，低温通过抑制小胶质细胞激活，包括小胶质细胞 iNOS 和促炎细胞因子的表达以及吞噬活性，减轻神经元损伤。研究低温条件下小胶质细胞激活调控的机制可能有助于开发新的神经保护治疗方法。
