中文摘要：

目的评价不同时机吸入异氟醚对新生大鼠缺氧缺血性脑损伤的影响。方法新生SD大鼠180只，7d龄，体重12—16g，采用随机数字表法，将大鼠随机分为6组（n=30）：假手术组（I组）、脑缺氧缺血组（Ⅱ组）、不同时机吸入异氟醚组（Ⅲ组-Ⅵ组）。采用结扎左颈总动脉和8％低氧处理2h的方法制备缺氧缺血性脑损伤模型。Ⅲ组-Ⅵ组分别于脑缺氧缺血后即刻、3、6和12h时吸入1．5％异氟醚30Min。于缺氧缺血后7d记录大鼠生存情况，随后处死，取脑组织，测定左、右大脑半球重量，计算左、右侧重量比。光镜下计数丘脑腹后内侧核和后扣带回皮层左、右侧正常神经元数量，计算左、右侧正常神经元密度比。结果与Ⅰ组比较，Ⅱ组-Ⅵ组左侧大脑半球的重量、左、右大脑半球重量比、丘脑腹后内侧核和后扣带回皮层左、右侧正常神经元密度比降低（P〈0．05）；与Ⅱ组比较，Ⅲ组-Ⅴ组左侧大脑半球的重量、左、右大脑半球重量比、丘脑腹后内侧核和后扣带回皮层左、右侧正常神经元密度比升高（P〈0．05），Ⅵ组上述指标差异无统计学意义（P〉0．05）。Ⅲ组～Ⅴ组间上述指标比较差异无统计学意义（P〉0．05）。Ⅱ组～Ⅵ组间生存率比较差异无统计学意义（P〉0．05）。结论新生大鼠脑缺氧缺血后6h内吸入1．5％异氟醚30min可减轻脑损伤。

英文摘要：

Objective To investigate the effects of inhalation of isoflurane at different time points on hy- poxic-ischemic brain injury in neonatal rats. Methods One hundred and eighty 7-day-old Sprague-Dawley rats, weighing 12-16 g, were randomly divided into 6 groups （ n = 30 each） ： sham operation group （groupⅠ ）, cerebral hypoxia/ischemia （H/I） group （group Ⅱ ）, and inhalation of isoflurane at different time point groups （groups Ⅲ-Ⅵ ）. Brain ischemia was induced by double ligation of left common carotid artery followed by inhalation of 8 % O2 ＋ 92 % N2 for 2 h at 37 ℃. In groups Ⅲ,Ⅳ,Ⅴ and Ⅵ 1.5 % isoflurane was inhaled for 30 min starting from 0, 3, 6, 12 h after H/I respectively, while the rats were exposed to 30% O2 and 70% N2 only in groups Ⅰ and Ⅱ. The survival rate at 7 days after H/I was recorded. The animals were sacrificed at 7 days after H/I. The brains were removed and the right and left cerebral hemispheres （CH） were weighed separately. The ratio between left/right CH was calculated. The density of normal neurons in ventral posterior inferior thalamic nucleus and poste- rior cingulate cortex in left and right CH were measured and the ratio of the density of normal neurons in the left to right CH was calculated. Results Compared with group Ⅰ, the weight of left cerebral hemisphere, ratio between left/right CH, and ratio of the density of normal neurons in the left to right CH were significantly decreased in other five groups （ P 〈 0.05）. Compared with group Ⅱ , the weight of left cerebral hemisphere, ratio between left/right CH, and ratio of the density of normal neurons in the left to right CH were significantly increased in groups Ⅲ,Ⅳ and Ⅴ （P 〈 0.05）. There were no significant differences in the indices mentioned above among groups Ⅲ,Ⅳ and Ⅴ（P 〉 0.05）. There was no significant difference in the survival rate among groups Ⅱ-Ⅵ （P 〉 0.05）. Conclusion Inhalation of 1.5% isoflurane for 30 min within 6 h after cerebral