Figure 1: Nerve injury induces marked microglial reaction in the ipsilateral lumbar spinal cord 7 days after chronic constriction injury (CCI). Microglia as demonstrated by CX3CR1 expression in CX3CR1-GFP mice. The contralateral side (left) shows the typical resting microglial morphology, and the ipsilateral side (right) illustrates the enlarged and amoeboid morphological features of activated microglia cell bodies. Also note that on the ipsilateral side the number and density of microglia in the medial superficial dorsal horn and lateral ventral horn, where injured primary afferent axons terminate, are significantly increased. Scale, 100 μm.