吸入不同浓度异氟醚对老龄大鼠海马细胞色素C表达的影响

Effects of inhalation of different concentrations of isoflurane on hippocampal cytochrome c expression in aged rats

目的评价吸入不同浓度异氟醚对老龄大鼠海马细胞色素c（Cytc）表达的影响。方法健康雄性老龄sD大鼠63只，月龄20月，体重500—600g，随机分为3组（n=21），对照组（c组）：吸入30％氧气2h；0．75％异氟醚组（I1组）：吸入0．75％异氟醚和30％氧气的混合气体2h；1．5％异氟醚组（I2组）：吸入1．5％异氟醚和30％氧气的混合气体2h。分别于麻醉30min、1和2h时，各组取5只大鼠，取动脉血样行血气分析。于麻醉结束后24h时，各组取8只大鼠，测定认知功能；取8只大鼠，分别采用免疫组化法和Westernblot法测定海马Cytc的表达水平。结果与c组比较，I1组和I2组逃避潜伏期延长，原平台象限停留时间缩短，穿越原平台次数减少，海马Cytc表达上调（P〈0．05）；与I1组比较，I2组逃避潜伏期、原平台象限停留时间缩短和穿越原平台次数差异无统计学意义（P〉0．05），海马Cytc表达上调（P〈0．05）。结论吸入异氟醚可通过上调海马Cytc的表达导致老龄大鼠认知功能障碍。

Objective To investigate the effects of inhalation of different concentrations of isoflurane on the expression of cytochrome c （ Cyt c） in hippocampus in aged rats. Methods Sixty-three aged male SD rats （20 months） weighing 500-600 g were randomly divided into 3 groups （ n = 21 each） ： control group inhaling 30% 02 for 2 h （group C） and 2 isoflurane groups anesthetized with 0.75% and 1.5% isoflurane in 30% Oz for 2 h respectively （group I1 and I2 ）. Arterial blood samples were obtained from 5 rats at 30 min, 1 and 2 h of anesthesia for blood gas analysis. Eight animals were killed at 24 h after anesthesia in each group. Their hippocampi were immediately removed for determination of Cyt c expression by immuno-histochcmistry and Western blot analysis. Cognitive function was assessed by Morris water maze test the day before experiment and once a day for 6 consecutive days starting from the 1st postoperative day. Results The Cyt c expression in hippocampus was significantly increased in I1 and I2 groups in a concentration-dependent manner as compared with group C. The escape latency was significantly prolonged and the frequency of crossing the original platform and the duration of staying at the original platform quadrant were decreased in group I1 and I2 compared with group C. Conclusion Inhalation of isoflurane anesthesia can decrease cognitive function through up-regulating the Cyt c expression in hippocampus in aged rats.