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

Neuropathic pain results from nerve injury and possesses adistinct disease mechanism compared to other types of chronic pain.Since it is associated with damage to the nervous tissue, studyinglipidome alterations related to neuropathic pain could constitutean important layer in the understanding of this condition. However,pain-related molecular changes remain poorly understood, particularlyin the brain. Here, we assessed the lipid abundances in two brainregions, namely, insular cortex (IC) and somatosensory cortex (S1)in rats that were subject to sciatic nerve constriction (SNC) injury—a commonanimal model of neuropathic pain, and compared them to the lipidomeof control rats that underwent a sham surgery. We found a significantincrease 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 lipidalterations in SNC correlated positively between regions, the amplitudeand significance of the lipid differences was larger in IC. In parallel,we analysed blood plasma lipids of the same rats and compared alterationsbetween the two types of tissue. The blood plasma lipidome mirroreddifferences found for the brain, in particular those related tothe lipids’ fatty acid composition. Taken together, these resultsindicate alterations in fatty acid metabolism as a possible markerassociated with neuropathic pain.