Structural and functional properties of spinal dorsal horn neurons after peripheral nerve injury change overtime via astrocyte activation.

Chronic pain remains challenging to treat, despite numerous reports of its pathogenesis, including neuronal plasticity in the spinal dorsal horn (SDH). We hypothesized that understanding plasticity only at a specific time point after peripheral nerve injury (PNI) is insufficient to solve chronic pain. Here, we analyzed the temporal changes in synaptic transmission and astrocyte-neuron interactions in SDH after PNI. We found that synaptic transmission in the SDH after PNI changed in a time-dependent manner, which was accompanied by astrocyte proliferation and loss of inhibitory and excitatory neurons. Furthermore, neuronal loss was accompanied by necroptosis. Short-term inhibition of astrocytes after PNI suppressed these physiological and morphological changes and long-term pain-related behaviors. These results are the first to demonstrate that the inhibition of astrocyte proliferation after PNI contributes to the long-term regulation of plasticity and of necroptosis development in the SDH.