Hippocampal Neurogenesis in Conditions of Chronic Stress Induced by Sciatic Nerve Injury in the Rat.

The dentate gyrus of the hippocampus is the primary location of adult neurogenesis, which is affected by a variety of external and internal factors, including activity of surrounding glial cells. This study concerns alterations in hippocampal neurogenesis and changes in activity of both proinflammatory and neuroprotective microglia/macrophages after sciatic nerve injury in the rat. Here, we demonstrated that the chronic pain induced by a peripheral nerve injury manifests in the hippocampus by a decrease in proliferation (PCNA+) and neurogenesis (DCX+), an increase in proinflammatory cytokines (CD86+), and a reduction in neuroprotective (CD163+) microglia/macrophages. We suggest that a pathological increase microglia/macrophage activity is the cause of neurogenesis suppression observed in chronic neuropathic pain.