Objective: To investigate the effect of ulinastatin pretreatment on isoflurane-induced mitochondria-dependent neuronal apoptosis in the hippocampus of rats.
Methods: Thirty-six male SD rats were randomly assigned into control group, isoflurane group and ulinastatin group. In the latter two groups, the rats were subjected to acute exposure to 0.75% isoflurane for 6 h and pretreated with 50 000 U/kg of ulinastatin before isoflurane exposure, respectively. After the treatments, apoptosis of the hippocampal neurons was detected using TUNEL assay, and the mitochondrial membrane potential (△ ψm) was measured using JC-1 mitochondrial membrane potential kit; cytochrome C release and caspase-3 activity were examined with Western blotting, and intracellular reactive oxygen species (ROS) was detected using the fluorescent probe H2DCFDA.
Results: Compared with those in the control group, the rats with acute exposure to isoflurane showed markedly increased TUNEL-positive cells in the hippocampus (P < 0.05), which were obviously reduced by ulinastatin pretreatment (P < 0.05). The △ψm of the hippocampal neurons was significantly reduced after isoflurane exposure (P < 0.05), and was partly recovered by ulinastatin pretreatment (P < 0.05). Acute exposure to isoflurane resulted in obviously increased cellular ROS, cytochrome C release and caspase-3 activity in the hippocampal neurons (P < 0.05), and these changes were significantly inhibited by ulinastatin pretreatment (P < 0.05).
Conclusions: Ulinastatin pretreatment provides neuroprotection against isoflurane-induced apoptosis of the hippocampal neurons in rats possibly by inhibiting mitochondria-dependent apoptosis pathway.
目的: 探讨乌司他丁预处理对异氟烷介导的大鼠海马神经元线粒体途径凋亡的影响及可能的机制。
方法: 36只SD雄性大鼠随机分为对照组、异氟烷组和乌司他丁组，每组12只。对照组不给与任何处理，异氟烷组和乌司他丁组采用0.75%异氟烷急性暴露6 h，而乌司他丁组在采用0.75%异氟烷急性暴露前，先给与50000 U/kg乌司他丁预处理。以TUNEL染色检测细胞凋亡，JC-1探针检测线粒体膜电位（△ψm），Western blot检测细胞色素C释放及caspase-3活性，H2DCFDA探针检测细胞内活性氧（ROS）。
结果: 与对照组比较，异氟烷组海马神经元凋亡显著增加（P < 0.05），而乌司他丁组显著下降（P < 0.05）；异氟烷组神经元线粒体△ψm显著降低（P < 0.05），乌司他丁组显著提高（P < 0.05）；异氟烷组海马神经元ROS、细胞色素C释放及caspase-3活性均显著增加（P < 0.05），而乌司他丁组显著降低（P < 0.05）。
结论: 乌司他丁可以抑制异氟烷介导的大鼠海马神经元凋亡，其机制可能与抑制线粒体途径凋亡有关。
Keywords: apoptosis; hippocampus; isoflurane; mitochondria; ulinastatin.