Rat primary cortical cell tri-culture to study effects of amyloid-beta on microglia function.

FITC-Aβ particles were more effectively cleared in the tri-culture compared to the co-culture. This was attributed to microglia engulfing FITC-Aβ particles, as confirmed via epifluorescence and confocal microscopy. Adding FITC-Aβ significantly increased the size of microglia, but had no significant effect on neuronal surface coverage or astrocyte size. Analysis of the cytokine profile upon FITC-Aβ addition revealed a significant increase in proinflammatory cytokines (TNF-α, IL-1α, IL-1β, IL-6) in tri-culture, but not co-culture. In addition, Aβ addition altered microglia motility marked by swarming-like motion with decreased Euclidean distance yet unaltered speed. These results highlight the importance of cell-cell communication in microglia function (e.g., motility and Aβ clearance) and the utility of the tri-culture model to further investigate microglia dysfunction in AD.