An in vitro Model of Neuron-macrophage Interaction to Generate Macrophages with Neurite Outgrowth Properties

Abstract

Macrophages are known to play beneficial roles in axon regeneration after nerve injury. To develop an in vitro model in which injury signals can elicit pro-regenerative macrophage activation, we established co-cultures consisting of adult dorsal root ganglia sensory neurons and peritoneal macrophages and added cAMP analogue dibutyryl cAMP. The conditioned medium collected from the co-cultures exhibited robust neurite outgrowth activities. The neurite outgrowth activities were almost completely abrogated by addition of minocycline, a macrophage deactivator, indicating that factors responsible for neurite outgrowth are produced by activated macrophages.