Objective To investigate the influence of propofol postconditioning on endoplasmic reticulum (ER) inositol-requiring enzyme 1 (IRE1)-X box binding protein 1 (XBP1) signaling pathway in oxygen-glucose deprivation/reperfusion (OGD/R) model of mouse neuroblastoma (N2a) cells.
Methods Mouse N2a cells were cultured to logarithmic growth stage. The cells were divided into 3 groups using random number table method: sham operation group (group C), OGD/R group (group O) and OGD/R plus propofol postconditioning group (group P). Cells in group C were cultured under normal condition, in the other 2 groups were cultured with oxygen glucose deprivation for 3 hours. Then cells in group O were cultured under normal condition for reperfusion for 24 hours, those in group P were incubated with propofol 50 μmol/L for 2 hours immediately during reperfusion, followed by culturing them under normal condition for 22 hours. The apoptosis rate of cells was detected by flow cytometry, the cell survival rate was detected by cell counting kit (CCK-8), the expression level of IRE1 and XBP1 protein and mRNA were detected with Western blot and qRT-PCR, the transmission electron microscope was used to observe the morphology of endoplasmic reticulum.
Results Compared with group C, the apoptosis rate was significantly increased (P < 0.05), the survival rate was significantly decreased (P < 0.05), the expression level of IRE1 and XBP1 protein and mRNA were significantly increased (P < 0.05) of cells in groups O and P. Compared with group O, the apoptosis rate was significantly decreased (P < 0.05), the survival rate was significantly increased (P < 0.05), the expression level of IRE1 and XBP1 protein and mRNA were significantly decreased (P < 0.05) of cells in group P. The result of transmission electron microscope showed that, the endoplasmic reticulum of cells in group C was normal, arranged regularly, and the rough endoplasmic reticulum was clearly visible; the endoplasmic reticulum of cells in group O was irregularly arranged, edematous, dilated, broken, and presenting cystic cistern, the rough endoplasmic reticulum was severely degranulated and partially fused with the cell membrane; the endoplasmic reticulum of cells in group P was slightly irregular, some endoplasmic reticulum showed mild edema and expansion, and the degranulation of the rough endoplasmic reticulum was less severe than that in group O.
Conclusion Propofol postconditioning can reduce the apoptosis of mouse N2a cells after OGD/R and increase the cell survival rate. Its mechanism may be related to inhibiting the ER IRE1-XBP1 signaling pathway and reducing the ER stress response. |
