CX3CL1 and injury: It has been suggested that macrophages play a neuroprotective role in the spiral ganglion; disruption of fractalkine signaling, one of the chemoattractants for macrophages, results in reduced macrophage infiltration and decreased SGN survival after cochlear trauma (Kaur et al., 2015, 2018; Stothert and Kaur, 2021).