High concentration sevoflurane induces apoptosis of neural stem cells by inhibiting VEGF/PI3K/AKT signaling pathway

Abstract

Objective To investigate the effects of sevoflurane exposure on apoptosis of neuronal cells and the mechanism in mid-pregnant rats. Method Rats in the second trimester of pregnancy were randomly divided into three groups, 48 pregnant rats in each group: control group, low concentration sevoflurane group and high concentration sevoflurane group. On the 14th day of pregnancy, pregnant rats were anesthetized with 2﹪ or 3.5﹪ sevoflurane for 2 hours. Neural stem cell apoptosis was examined by immunofluorescence. Brain tissues were collected at 6, 24 and 48 hours after anesthesia and on days 0, 14 and 28 after birth for Nestin-TUNEL double labeling immunofluorescence staining and immunoblotting for Nestin, vascular endothelial growth factor (VEGF) and phosphoinositol 3-kinase (PI3K)-AKT pathway-related proteins. One-way ANOVA and Bonferroni post-test were used for statistical analysis. Results The percentage of Nestin and TUNEL positive cells in the brain tissue increased at 6, 24 and 48 hours after anesthesia, as well as P 0, P 14 and P 28 (At 6 h, the control group was 0.91±0.07; the low concentration group was 1.01±0.08; and the high concentration group was 2.62±0.21, F = 399, P < 0.01; at 24 h, the control group was 0.96±0.04; the low concentration group was 1.09±0.13; and the high concentration group was 1.89±0.14, F = 364.37, P < 0.01; at 48 h the control group was 0.95±0.05; the low concentration group was 1.09±0.13; and the high concentration group was 1.69±0.19, F = 524.52, P < 0.01; at P 0 the control group was 0.97±0.03; the low concentration group was 1.01±0.09; the high concentration group was 2.21±0.15, F = 378.31, P < 0.01; at P 14, the control group was 0.96±0.03; the low concentration group was 1.22±0.12; and the high concentration group was 1.89±0.14, F = 158.33, P < 0.01; at P 28, the control group was 0.95±0.05; the low concentration group was 1.09±0.13; and the high concentration group was 1.69±0.19, F = 66.83, P < 0.01, but the level of Nestin protein in the high concentration group decreased. At 6 h the control group was 0.95±0.08, the low concentration group was 0.81±0.11, the high concentration group was 0.62±0.13, F = 18.60, P < 0.01; at 24 h the control group was 0.92±0.06, the low concentration group was 0.85±0.13, the high concentration group was 0.74±0.12, F = 5.66, P = 0.0108; the high concentration group was 0.74±0.12; at 48 h the control group was 0.95±0.04, the low concentration group was 0.80±0.08, the high concentration group was 0.72±0.14, F = 11.86, P < 0.01; at P 0 the control group was 0.97±0.06, the low concentration group was 0.72±0.09, the high concentration group was 0.67±0.09, F = 31.31, P < 0.01; at P 14 the control group was 0.94±0.03, the low concentration group was 0.69±0.07, the high concentration group was 0.65±0.13, F = 26.11, P < 0.01; at P 28 the control group was 0.95±0.08, the low concentration group was 0.91±0.12, the high concentration group was 0.58±0.13, F = 26.25, P < 0.01. The levels of vascular endothelial growth factor, PI3K and phosphorylated AKT (p-AKT) in the fetal rat brain decreased 6 hours after anesthesia (P < 0.05). However, there was no significant change in low concentration sevoflurane exposure group. Conclusion Exposure to sevoflurane in the second trimester of pregnancy can decrease the levels of vascular endothelial growth factor, PI3K and p-AKT proteins and induce apoptosis of neural stem cells, leading to learning and memory dysfunction in the offsprings. Key words: Sevoflurane; VEGF/PI3K/AKT; Neural stem cells; Apoptosis; Pregnancy