Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University.
Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi.
J Toxicol Sci. 2019;44(7):471-479. doi: 10.2131/jts.44.471.
M1-microglia (neurotoxic microglia) regulate neuronal development and cell death and are involved in many pathologies in the brain. Although organotypic brain slice cultures are widely used to study the crosstalk between neurons and microglia, little is known about the properties of microglia in the mouse cerebral cortex slices. Here, we aimed to optimize the mouse cerebral slice cultures that reflect microglial functions and evaluate the effects of neurotoxic metals on M1-microglial activation. Most microglia in the cerebral slices prepared from postnatal day (P) 7 mice were similar to mature microglia in adult mice brains, but those in the slices prepared from P2 mice were immature, which is a conventional preparation condition. The degree of expression of M1-microglial markers (CD16 and CD32) and inflammatory cytokines (tumor necrosis factor-α and interleukin-1β) by lipopolysaccharide, a representative microglia activator, in the cerebral slices of P7 mice were higher than that in the slices of P2 mice. These results indicate that M1-microglial activation can be evaluated more accurately in the cerebral slices of P7 mice than in those of P2 mice. Therefore, we next examined the effects of various neurotoxic metals on M1-microglial activation using the cerebral slices of P7 mice and found that methylmercury stimulated the activation to M1-microglia, but arsenite, lead, and tributyltin did not induce such activation. Altogether, the optimized mouse cerebral slice cultures used in this study can be a helpful tool to study the influence of various chemicals on the central nervous system in the presence of functionally mature microglia.
M1 型小胶质细胞（神经毒性小胶质细胞）调节神经元的发育和死亡，并参与大脑中的许多病理过程。尽管器官型脑片培养广泛用于研究神经元和小胶质细胞之间的相互作用，但对于小鼠大脑皮层切片中小胶质细胞的特性知之甚少。在这里，我们旨在优化反映小胶质细胞功能的小鼠大脑切片培养，并评估神经毒性金属对 M1 型小胶质细胞激活的影响。从出生后第 7 天（P）的小鼠制备的脑片中的大多数小胶质细胞与成年小鼠大脑中的成熟小胶质细胞相似，但从 P2 天的小鼠制备的脑片中的小胶质细胞不成熟，这是一种常规的制备条件。脂多糖（一种代表性的小胶质细胞激活剂）在 P7 天小鼠脑片中表达 M1 型小胶质细胞标志物（CD16 和 CD32）和炎症细胞因子（肿瘤坏死因子-α和白细胞介素-1β）的程度高于 P2 天小鼠脑片中的程度。这些结果表明，与 P2 天小鼠脑片相比，P7 天小鼠脑片中 M1 型小胶质细胞的激活可以更准确地评估。因此，我们接下来使用 P7 天小鼠的脑片研究了各种神经毒性金属对 M1 型小胶质细胞激活的影响，发现甲基汞刺激 M1 型小胶质细胞的激活，但砷酸盐、铅和三丁基锡没有诱导这种激活。总之，本研究中优化的小鼠大脑切片培养物可作为一种有用的工具，用于研究各种化学物质在具有功能成熟小胶质细胞的情况下对中枢神经系统的影响。
