Microglial morphology in the somatosensory cortex across lifespan. A quantitative study

BackgroundMicroglia are long-lived cells that constantly monitor their microenvironment. To accomplish this task, they constantly change their morphology both in the short and long term under physiological conditions. This makes the process of quantifying physiological microglial morphology difficult. ResultsBy using a semi-manual and a semi-automatic method to assess fine changes in cortical microglia morphology, we were able to quantify microglia changes in number, surveillance and branch tree starting from the fifth postnatal day to 2 years of life. We were able to identify a fluctuating behavior of most analyzed parameters characterized by a rapid cellular maturation, followed by a long period of relative stable morphology during the adult life with a final convergence to an aged phenotype. Detailed cellular arborization analysis revealed age-induced differences in microglia morphology, with mean branch length and the number of terminal processes changing constantly over time. ConclusionsOur study provides insight into microglia morphology changes across lifespan under physiological conditions. We were able to highlight, that due to the dynamic nature of microglia several morphological parameters are needed to establish the physiological state of these cells.

Automated summary

This study used a semi-manual and semi-automatic method to quantify fine changes in microglia morphology in the cortex from the fifth postnatal day to 2 years of age. The results showed a fluctuating behavior of microglia morphology, with rapid cellular maturation, stable morphology in adulthood, and a convergence to an aged phenotype. Detailed analysis also revealed age-induced differences in microglia morphology, with changes in branch length and the number of terminal processes over time.