Src is Implicated in Hepatic Ischemia Reperfusion-Induced Hippocampus Injury and Long-Term Cognitive Impairment in Young Mice via NMDA Receptor Subunit 2A Activation

Hepatic ischemia reperfusion (HIR) has been found to induce hippocampus injury and cognitive dysfunction. The N-methyl-d-aspartate (NMDA) receptor subunit 2A (NR2A) is an important factor mediating excitotoxicity and neurons injury, and autophosphorylation of Src can up-regulate tyrosine phosphorylation of NR2A to improve its activity. However, the role of Src and NR2A in HIR-induced hippocampus injury in young mice remains unknown. In this study, we found that serum biomarkers of brain injury (S100β and NSE) increased significantly and reached highest after reperfusion of 3 days which had the same trend with the levels of p-Src and p-NR2A. Interactions between Src and NR2A or PSD95 were increased after HIR. Hippocampal neuron apoptosis was increased, and long-term cognitive impairment was found after reperfusion of 1 month. Inhibition of Src and NR2A with PP2 and NVP-AAM077 respectively not only down-regulated the levels of p-Src and p-NR2A, but also ameliorated hippocampal neurons apoptosis and long-term cognitive impairment after HIR. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), tumor necrosis factor α (TNF-α), interferon-γ (IFN-γ) and interleukin (IL)-6 were increased after reperfusion of 3 days, while PP2 and NVP-AAM077 treatment didn't attenuate the changes. And no difference was found in serum TNF-α, IFN-γ, IL-6 concentrations as well as the levels of Src, p-Src, NR2A, p-NR2A, PSD95 among the four groups after reperfusion of 1 month. In summary, HIR can lead to hippocampus injury and long-term cognitive dysfunction, and Src-PSD95-NR2A pathway plays an important role in the process.