[Effects of blocking lactate production by 2-DG on hypoxic injury of HT22 neurons and its mechanisms].

Objective: To investigate the effects of blocking lactate synthesis on the HT22 cell injuries caused by hypoxia.

Methods: 2-deoxy-D-glucose (2-DG) is a non-metabolized glucose analogue that can inhibit lactate synthesis by blocking glycolysis. HT22 cells were divided into 4 groups: Control group, 2-DG group, Hypoxia group and 2-DG+Hypoxia group. The cells in control group and 2-DG treatment group were cultured in a 37℃, 5% CO₂ incubator, and thecells in hypoxia group and 2-DG + Hypoxia group were cultured in a hypoxia incubator. The concentrations of 2-DG were 2.5 and 5 mmol/L, the concentration of oxygen was 0.3%, and the treatment time was 24 h. Cell activity was detected by CCK-8 assay, the levels of lactate in cell culture medium were detected by spectrophotometry, cell morphology was observed by fluorescence staining, the level of reactive oxygen species (ROS) was detected by flow cytometry, and the activities of superoxide dismutase (SOD) and catalase (CAT) were determined by enzyme activity kits. The protein expression levels of p-p38, t-p38 and β-actin were detected by Western blot.

Results: Compared with that in control group, the lactate level in culture medium and cell activity were decreased significantly (P＜0.01), the number of adherent cells was decreased, the level of ROS was increased (P＜0.01), and the enzyme activity of CAT was decreased (P＜0.05) in the 2-DG group. In the hypoxia group, the level of lactate in the culture medium was increased significantly (P＜0.01), the cell activity was decreased (P＜0.01), the number of adherent cells was decreased, the ROS levels were increased (P＜0.01), and the enzyme activities of CAT and SOD were decreased (P＜0.01 or P＜0.05). In 2-DG+Hypoxia group, the level of lactate was decreased significantly (P＜0.05), the cell viability was decreased significantly (P＜0.01), the number of cells was decreased significantly, and the ability of adhere to the wall was weakened significantly. The level of ROS was increased significantly (P＜0.01), the enzyme activities of CAT and SOD were decreased significantly (P＜0.01), the protein expression level of p-p38 was increased significantly (P＜0.05), and there was no change in t-p38. Compared with hypoxia groups, in 2-DG combined with hypoxia group, the level of lactate induced by hypoxia, the cell activity, and the enzyme activity level of CAT were decreased significantly (all P＜0.01), while the level of ROS was increased significantly (P＜ 0.01).

Conclusion: Blocking lactate can reduce the cell activity level under hypoxia and aggravate the oxidative stress injury of HT22 cells. The mechanisms may be related to increasing ROS level and activating p38 signal pathway.