Lipidome Alterations in Brain and Blood Plasma in Rats with Sciatic Nerve Injury

Neuropathic pain results from nerve injury and possesses a distinct disease mechanism compared to other types of chronic pain. Since it is associated with damage to the nervous tissue, studying lipidome alterations related to neuropathic pain could constitute an important layer in the understanding of this condition. However, pain-related molecular changes remain poorly understood, particularly in the brain. Here, we assessed the lipid abundances in two brain regions, namely, insular cortex (IC) and somatosensory cortex (S1) in rats that were subject to sciatic nerve constriction (SNC) injury—a common animal model of neuropathic pain, and compared them to the lipidome of control rats that underwent a sham surgery. We found a significant increase of lipids containing particular fatty acids (22:5, 20:3) in SNC rats compared to controls. On the level of lipid classes, we detected increased levels of lysophosphatidylethanolamines (LPE) and decreased levels of phosphatidylethanolamines (PE). While lipid alterations in SNC correlated positively between regions, the amplitude and significance of the lipid differences was larger in IC. In parallel, we analysed blood plasma lipids of the same rats and compared alterations between the two types of tissue. The blood plasma lipidome mirrored differences found for the brain, in particular those related to the lipids’ fatty acid composition. Taken together, these results indicate alterations in fatty acid metabolism as a possible marker associated with neuropathic pain.