To investigate the mechanism underlying L-4F treatment-induced neuroprotection in T2DM, the macrophage infiltration was measured by ED1 protein level, and the protein and mRNA levels of HMGB1, RAGE, TNFα, and PAI-1 were measured by using immunostaining, WB or RT-PCR assay, respectively. Here, HMGB1 is linked to type 2 diabetes mellitus.