Soluble epoxide hydrolase (Ephx2) silencing attenuates the hydrogen peroxide-induced oxidative damage in IEC-6 cells

Oxidative stress can cause intestinal disease. Soluble epoxide hydrolase (sEH, Ephx2) is related to cell apoptosis. The effect of Ephx2 on the H₂O₂-induced oxidative damage remains unclear. Thus, we aimed to explore the effect of Ephx2 on oxidative damage and the underlying potential mechanism.

The cell viability was determined using cell counting kit-8 (CCK-8) assay. The reactive oxygen species (ROS), apoptosis, and mitochondrial membrane potential (MMP) were examined using flow cytometry analysis. Commercial kits were applied to respectively determine the lactate dehydrogenase (LDH) leakage, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity. The expressions of target factors were measured by conducting quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blot.

We found that knockdown of Ephx2 enhanced the viability of H₂O₂-treated IEC-6 cells, and that si-Ephx2 reduced the ROS level, MMP loss, and apoptosis in comparison to the H₂O₂ model group. Knockdown of Ephx2 was found to decrease LDH activity and MDA content, and to improve the SOD activity in comparison to those in the H₂O₂ model group. Knockdown of Ephx2 reduced the expressions of Fas, Fasl, Bax, and cleavedcaspase-3 and elevated the expression of Bcl-2 in H₂O₂-treated IEC-6 cells. Furthermore, we observed that knockdown of Ephx2 enhanced the phosphorylation of PI3K, Akt, and GSK3β, which were reduced by the treatment of H₂O₂. In addition, the anti-apoptotic effect of si-Ephx2 was enhanced in the presence of AUDA-pharmacological Ephx2 inhibitor.

Ephx2 silencing inhibited H₂O₂-induced oxidative damage. The PI3K/Akt/GSK3β pathway was related to the effect of si-Ephx2. Our study provided a potential target for the prevention of intestinal injury.