Neuron-astrocyte interactions in spinal cord dorsal horn in neuropathic pain development and docosahexaenoic acid therapy

•DHA reduced the intensity and duration of neuropathic pain.•Also it stabilized weight bearing, prevented the development of cold allodynia.•DHA treatment reduced reactive astrocyte in spinal cord of neuropathic pain rats.•This drug decreases the activity of SP-immunopositive fibers and nNOS-positive neurons in the SCDH.

The analgesic activity of docosahexaenoic acid (DHA, 22:6 n − 3) was studied using a chronic constriction injury (CCI) rat model. Animals were subcutaneously injected with DHA emulsion at a dose of 4.5 mg/kg (125 mМ/kg) daily during 2 weeks after surgery. We characterized the dynamics of GFAP-positive astrocyte, substance P (SP) and nNOS-positive neurons activity in the spinal cord dorsal horn (SCDH) superficial lamina. We found that DHA treatment decrease the intensity and duration of neurogenic pain syndrome, results in earlier stabilization of weight distribution, prevents the cold allodynia and dystrophic changings in denervated limb tissue. DHA treatment reduced the reactive astrocyte number, decrease SP-immunopositive fibers and nNOS-positive neurons number in the SCDH in neuropathic pain.