Effect of isoflurane preconditioning on glutamate-induced apoptosis in rat neuronal PC12 cells

Abstract

Objective To investigate the effect of isoflurane preconditioning on glutamate-induced apoptosis in rat neuronal PC12 cells.Methods The PC12 cells were cultured for 5 d with nerve growth factor in vitro.The cells were seeded into 6-cm-diameter culture dishes (3 ml/dish) or 6-well plates (2 ml/well) with the density of 5 × 104/ml and randomly divided into 4 groups (n =18 each): normal control group (group C); glutamate group (group G) ;glutamate + isoflurane group (group GI) and glutamate + isoflurane + xestospongin C (an antngon of inositol trisphosphate receptors) group (group GIX).The neuronal PC12 cells were exposed to glutamate 500 μmol/L in groups G,GI and GIX.The neuronal PC12 cells were exposed to 1.2％ isoflurane for 2 h in groups GI and GIX.Xestospongin C was added to the culture medium immediately before isoflurane preconditioning.Glutamate was added to the culture medium at 10 min after isoflurane preconditioning in groups GI and GIX.The cells were collected from six dishes or wells in each group after being incubated with glutamate for 20 min.The apoptosis and mitochondiral membrane potential (MMP) were assessed by flow cytometry.Intracellular Ca2+ concentration ([ Ca2+ ] i)was detected by confocal fluorescence microscopy.Results Compared with group C,the apoptotic rate and [Ca2+ ]i were significantly increased and MMP was decreased in groups G and GIX ( P ＜ 0.01 ),but there was no significant difference in the variables mentioned above in group GI (P ＞ 0.05).Compared with group G,the apoptotic rate and [ Ca2 + ]i were significantly decreased and MMP was increased in groups GI and GIX ( P ＜ 0.05 or 0.01).Compared with group GI,the apoptotic rate and [Ca2+ ]i were significantly increased and MMP was decreased in group GIX ( P ＜ 0.01 ).Conclusion Isollurane preconditioning can inhibit apoptosis in rat neuronal PC12 cells by activating inositol trisphosphate receptors,inhibiting Ca2+ release from the endoplasmic reticulum and increasing MMP. Key words: Isoflurane; Ischemic preconditioing; Glutamic acid; PC12 cells; Neurons; Apoptosis