Isolation of Hypothalamic Microglia from Freshly Perfused Adult Mouse Brain by Magnetic-Activated Cell Sorting

Microglia, as the resident macrophages of the brain, are essential for maintaining brain homeostasis. They shape neuronal circuits during development, survey their environment for debris or dead cells, as well as respond to infection and injury in the brain, among many other functions. However, their important role in neurodevelopment and synaptic plasticity and pathophysiology has not been fully defined, highlighting the need for further investigation. To gain a more comprehensive understanding of the role of microglia in these processes, we need to isolate microglia and characterize them genetically, metabolically, and functionally. However, the isolation of microglia from adult mice, especially from small brain structures, is challenging as they represent a small percentage of the total brain cells, and the yield of isolated microglia is often too low. Here, the magnetic isolation of microglia using CD11b⁺ microbeads allows us to sort microglial cells from the hypothalamus of a freshly perfused adult mouse brain. The current method allows us to achieve relatively high purity and yield in a short period while maintaining cell viability.