Microglia Culture: Isolating and Studying the Brain's Immune Cells

🕒 Approximate reading time: 4 minutes

Microglia, the primary immune cells of the brain, are integral to maintaining neural homeostasis and responding to injuries or diseases. The ability to culture these cells in vitro has greatly enhanced our understanding of their role in neurological conditions, such as amyotrophic lateral sclerosis (ALS).

The Steps Involved in Microglia Culture

  1. Tissue Dissection: Microglia are typically isolated from brain tissue, often derived from neonatal mice. The brain tissue is carefully dissected and the meninges, the layers of tissue covering the brain, are removed.

  2. Enzymatic Dissociation: The tissue is then enzymatically dissociated using an enzyme like collagenase or trypsin. This process breaks down the extracellular matrix and cell-cell connections, freeing the individual cells.

  3. Centrifugation and Resuspension: The dissociated cells are then centrifuged, and the cell pellet is resuspended in a suitable medium to create a cell suspension.

  4. Density Gradient Separation: A density gradient centrifugation step can be included to enrich for microglia. During centrifugation, the cells separate based on their size and density, allowing for the collection of a microglia-enriched fraction.

  5. Plating and Culture: The isolated microglia are plated onto tissue culture plates and incubated in a controlled environment, where they can adhere, grow, and divide.

Studying Microglia in Culture

Once microglia are in culture, they can be studied in several ways. For instance, researchers may:

  1. Analyse their Morphology: Microglia have distinct morphological states, ranging from a ramified (resting) state to an amoeboid (activated) state. Observing these changes can provide insights into their functional status.

  2. Examine their Protein Expression: Immunofluorescence staining or Western blotting can be used to assess the expression of specific proteins, such as markers of activation or inflammation.

  3. Monitor their Phagocytic Activity: Microglia play a crucial role in clearing debris and dead cells from the brain. Assays that track the uptake of labelled particles can help study this function in vitro.

  4. Investigate their Response to Stimuli: Microglia can be exposed to various stimuli, such as pro-inflammatory cytokines or components of pathogens, to understand their response mechanisms.

Microglia Culture in the Context of Neurodegenerative Diseases

Cultured microglia have been instrumental in studying neurodegenerative diseases like ALS:

  1. Modelling Disease Mechanisms: Microglia from transgenic animals modelling ALS can help unravel disease-specific changes in microglial function.

  2. Investigating Neuroinflammation: In ALS and other neurodegenerative conditions, microglia often exhibit an activated, pro-inflammatory state. Cultured microglia can help us understand the triggers and consequences of this inflammation.

  3. Screening Therapeutics: Microglial cultures can also be used to screen potential therapeutics that aim to modulate microglial function or reduce neuroinflammation.


The cultivation of microglia has provided researchers with a valuable tool for studying these essential brain cells. Through the continued refinement of microglial culture techniques, we are poised to gain further insights into the role of these cells in health and disease, potentially paving the way for novel therapeutic strategies in neurodegenerative diseases such as ALS.