Microglial Morphometric Parameters Correlate With the Expression Level of IL-1β, and Allow Identifying Different...

Area of Science:

• Neuroscience
• Immunology
• Cell Biology

Background:

• Microglia, the brain's resident macrophages, traditionally exhibit resting or activated states.
• Intermediate microglial morphologies are observed during pathological conditions, suggesting a more complex activation spectrum.
• The relationship between microglial morphology and function necessitates quantitative analysis of activation states.

Purpose of the Study:

• To objectively correlate microglial morphology with the degree of inflammatory activation.
• To investigate the dynamic changes in microglial shape during neuroinflammation.
• To identify distinct morphotypes of activated microglia.

Main Methods:

• A rat model of neuroinflammation induced by neuraminidase (NA) injection.
• Co-immunolabeling with IBA1 (microglial marker) and IL-1β (inflammatory marker).
• Quantitative analysis of 15 morphological parameters and IL-1β expression levels in microglia.

Main Results:

• Microglial morphology progressively changes with increasing IL-1β expression, indicating gradual activation.
• A hierarchical cluster analysis revealed four distinct morphotypes of activated microglia.
• Each morphotype was characterized by specific morphological parameters and IL-1β expression levels.

Conclusions:

• Microglial activation is a continuous process that correlates with morphological alterations.
• Distinct activated microglial morphotypes can be objectively categorized based on shape and activation degree.
• The physiological relevance of these activated morphotypes warrants future investigation.