Proper myelin formation by oligodendrocytes on neuronal axons is essential for brain function. Demyelination causes various neurodegenerative diseases, but the cellular and molecular mechanisms underlying demyelination remain unclear. Here, we developed a slice culture system to examine neuron-glia interactions during demyelination.

To prepare slice cultures, postnatal-6-day mouse brains were sectioned, and then the cortical slices containing the corpus callosum were cultured. By immunostaining cultured slices for the myelin marker Myelin basic protein and the axonal marker Neurofilament, we confirmed that axons are myelinated in the corpus callosum until days in vitro 15. Next, we attempted to induce demyelination in the slice culture system by applying lysophosphatidylcholine (LPC), which is an endogenous lysophospholipid, from days in vitro 14 to days in vitro 15. LPC application induced a decrease in colocalization of Myelin basic protein and Neurofilament, which we defined as demyelination, compared to the control group. Additionally, we found that microglia engulf myelin debris around the demyelinated axons.

Thus, we developed a slice culture system in which demyelination and surrounding microglial response to demyelination can be investigated.