Glial cells can mediate hypothalamic inflammatory processes induced in response to a high-fat diet (HFD). We used magnetic-activated cell sorting (MACS) to isolate microglia and astrocytes from hypothalamus of mice fed HFD and examined changes in expression of inflammation-related cytokines and markers related to glial cell activation status.

Hypothalamus from male C57BL6 mice fed a chow diet (chow) or HFD for 1, 3, or 28 days were collected and microglia and astrocytes were isolated by MACS. After confirming cell viability by fluorescence activated cell sorting, mRNA expression levels of inflammation-related cytokines and markers of glial cell activation status were examined by qRT-PCR, which revealed that both glial cell types isolated by MACS retained specificity.

On day 3 of HFD, both CD86 and TNFα mRNA expression was significantly increased in microglia relative to the chow group. In astrocytes, TNFα mRNA expression levels were similar between the chow and HFD groups on day 3, but anti-inflammatory cytokine IL-10 levels were significantly increased. On day 7 of HFD, TNFα expression in microglia decreased to levels comparable to the chow group while that in astrocytes remained unchanged. On day 28 of HFD, TNFα levels were significantly increased in both microglia and astrocytes, which had increased mRNA expression of CD86 and MAO-B, respectively. For both glial cell types, results for TNFα expression assessed by RT-PCR and immunohistochemical analysis were similar.

These results indicate that the role of microglia and astrocytes in hypothalamic inflammation under HFD conditions changed with time and these changes were accompanied by changes in the activation status of glial cells. Our data suggest that early after initiating HFD, hypothalamic astrocytes suppress diet-induced inflammation at least in part by secreting IL-10, whereas continued HFD feeding impairs this suppressive function such that both microglia and astrocytes promote hypothalamic inflammation.

胶质细胞可以介导响应高脂饮食（HFD）诱导的下丘脑炎症过程。我们使用磁激活细胞分选术（MACS）从喂食HFD的小鼠的下丘脑中分离出小胶质细胞和星形胶质细胞，并检查了炎症相关细胞因子和与神经胶质细胞激活状态相关的标志物的表达变化。

从雄性C57BL6小鼠喂食日粮（食物）或HFD，持续1、3或28天的下丘脑，并通过MACS分离小胶质细胞和星形胶质细胞。通过荧光激活细胞分选确认细胞活力后，通过qRT-PCR检查炎症相关细胞因子的mRNA表达水平和神经胶质细胞活化状态的标志物，这表明通过MACS分离的两种神经胶质细胞类型均保留特异性。

在HFD的第3天，小胶质细胞中的CD86和TNFαmRNA表达均相对于食物组显着增加。在星形胶质细胞中，第3天，高脂饮食组和HFD组之间的TNFαmRNA表达水平相似，但抗炎细胞因子IL-10的水平显着升高。在HFD的第7天，小胶质细胞中的TNFα表达下降到与松狮组相当的水平，而星形胶质细胞中的TNFα表达保持不变。在HFD的第28天，小胶质细胞和星形胶质细胞中的TNFα水平均显着升高，而CD86和MAO-B的mRNA表达则分别升高。对于两种神经胶质细胞类型，通过RT-PCR和免疫组织化学分析评估的TNFα表达结果均相似。

这些结果表明，在HFD条件下小胶质细胞和星形胶质细胞在下丘脑炎症中的作用随时间变化，并且这些变化伴随神经胶质细胞激活状态的变化。我们的数据表明，在开始HFD的早期，下丘脑星形胶质细胞至少部分地通过分泌IL-10抑制饮食诱导的炎症，而持续的HFD喂养会削弱这种抑制功能，从而使小胶质细胞和星形胶质细胞均促进下丘脑炎症。