异氟醚和七氟醚对新生大鼠皮质凋亡以及JNK和p38表达的不同影响

目的: 研究同等剂量的异氟醚和七氟醚对新生大鼠皮质神经元凋亡的影响以及对JNK和p38蛋白表达的不同影响。方法: 55只出生后7 d(P7)的新生大鼠(共5窝,每窝取11只),随机均分为异氟醚组(Ⅰ组)、七氟醚组(S组)和对照组(C组),各组分别吸入1.1%异氟醚、1.8%七氟醚和空气4 h。在麻醉结束后2 h每窝每组各取1只幼鼠灌注取脑,免疫组织化学法检测皮质压部后区caspase-3表达(n=5);另外,每窝C组在麻醉处理0 h,Ⅰ组和S组分别在麻醉2 h、4 h取新鲜脑皮质,Western blotting检测磷酸化SAPK/JNK、磷酸化p38,以及SAPK/JNK、p38表达的变化(n=5)。结果: Ⅰ组和S组caspase-3表达分别较对照组增加441%(P<0.01)和151%(P<0.01),Ⅰ组比S组增加115%(P<0.05);Ⅰ组磷酸化SAPK/JNK表达在麻醉2 h和4 h较对照组分别增加219%(P<0.05)和181%(P<0.05),S组在2 h和4 h均与对照组无显著差异;Ⅰ组磷酸化p38表达在麻醉2 h和4 h较对照组分别增加38.9%(P<0.05)和36.9%(P<0.05),S组在2 h和4 h较对照组分别增加32.6%(P<0.05)和128.0%(P<0.01)。结论: 0.5最低肺泡有效浓度(MAC)异氟醚比七氟醚诱导更多新生大鼠大脑皮质神经元凋亡,异氟醚诱导凋亡可能与激活SAPK/JNK磷酸化有关,而七氟醚诱导凋亡可能与激活p38磷酸化有关。

Effects of isoflurane and sevoflurane on apoptosis of cortical neuron in neonatal rats and the role of MAPKs pathway

AIM: To investigate the effects of isoflurane and sevoflurane at the same dose on apoptosis of cortical neuron in neonatal rats and the role of mitogen-activated protein kinases (MAPKs) pathway.METHODS: Eleven neonatal rats were selected at postnatal day 7 from 1 litter (altogether 5 litters) and assigned randomly into control group (C group), isoflurane group (Ⅰ group) and sevoflurane group (S group). The rats in Ⅰ group, S group or C group were exposed to 1.1% isoflurane, 1.8% sevoflurane and room air for 4 h, respectively. The brain of neonatal rats were perfused and embedded by paraffin. Caspase-3 positive expression in the retrosplenial cortex (RS) of the brain was observed by immunohistochemical staining. Meanwhile, the fresh cortex was separated at 0 h in C group and at 2 h and 4 h in Ⅰ group and S group. The levels of phospho-SAPK/JNK and SAPK/JNK, phospho-p38 and p38 in fresh cortex were detected by Western blotting.RESULTS: Caspase-3 positive cells in the the cortex were increased by 441% in Ⅰ group (P<0.01) and 151% in S group (P<0.01) as compared to C group, and increased by 115% in Ⅰ group (P<0.05) as compared to S group. The protein levels of phospho-SAPK/JNK in the cortex were increased by 219% at 2 h (P<0.05) and 181% at 4 h (P<0.05) in Ⅰ group, while no significant difference between S group and C group was observed. The phospho-p38 protein in the cortex was increased by 38.9% at 2 h (P<0.05) and 36.9% at 4 h (P<0.05) in Ⅰ group, and increased by 32.6% (P<0.05) at 2 h and 128.0% at 4 h (P<0.01) in S group as compared to C group.CONCLUSION: Isoflurane induces more apoptotic neurons in the cortex of the brain in neonatal rats at postnatal day 7 than sevoflurane. Isoflurane induces apoptosis mainly by activating SAPK/JNK phosphorylation, while sevoflurane induces aopotosis by activating p38 phosphorylation.