Hyperglycemia disrupted the integrity of the blood‐brain barrier following diffuse axonal injury through the sEH/NF‐κB pathway

Abstract Objectives We aimed to investigate the role of soluble epoxide hydrolase for hyperglycemia induced‐disruption of blood‐brain barrier (BBB) integrity after diffuse axonal injury (DAI). Methods Rat DAI hyperglycemia model was established by a lateral head rotation device and intraperitoneal injection of 50% glucose. Glial fibrillary acidic protein, ionized calcium‐binding adapter molecule‐1, β‐amyloid precursor protein, neurofilament light chain, and neurofilament heavy chain was detected by immunohistochemistry. Cell apoptosis was examined by terminal deoxynucleotidyl transferase nick‐end labeling (TUNEL) assay. The permeability of blood‐brain barrier (BBB) was assessed by expression of tight junction proteins, leakage of Evans blue and brain water content. The soluble epoxide hydrolase (sEH) pathway was inhibited by 1‐trifluoromethoxyphenyl‐3‐(1‐propionylpiperidin‐4‐yl) urea (TPPU) and the nuclear transcription factor kappa B (NF‐κB) pathway was inhibited by pyrrolidine dithiocarbamate and activated by phorbol‐12‐myristate‐13‐acetate in vivo and/or vitro, respectively. The inflammatory factors were detected by enzyme‐linked immunosorbent assay. Results Hyperglycemia could exacerbate axonal injury, aggravate cell apoptosis and glial activation, worsen the loss of BBB integrity, increase the release of inflammatory factors, and upregulate the expression of sEH and NF‐κB. Inhibition of sEH could reverse all these damages and protect BBB integrity by upregulating the expression of tight junction proteins and downregulating the levels of inflammatory factors in vivo and vitro, while the agonist of NF‐κB pathway abrogated the protective effects of TPPU on BBB integrity in vitro. Conclusions sEH was involved in mediating axonal injury induced by hyperglycemia after DAI by disrupting BBB integrity through inducing inflammation via the NF‐κB pathway.