短时间吸入不同浓度七氟醚对幼鼠空间学习记忆能力及海马神经细胞凋亡的影响

Influence of inhaling different concentrations of sevoflurane in a short time on spatial learning and memory ability and hippocampal neuronal apoptosis in immature rats

目的观察短时间吸入不同浓度七氟醚对幼鼠空间学习记忆能力及海马神经细胞凋亡的影响。方法选择80只SD幼鼠,均为1月龄,采取随机数字表法将幼鼠分为对照组(单纯吸氧2 h)、1%七氟醚组(吸入1%七氟醚2 h)、2%七氟醚组(吸入2%七氟醚2 h)与3%七氟醚组(吸入3%七氟醚2 h),每组20只。吸入结束12 h后,各组取5只开展Morris水迷宫实验,5只取海马组织行苏木精-伊红染色,5只通过流式细胞分析仪进行细胞凋亡测定,5只通过激光共聚焦显微镜进行神经元细胞游离钙离子浓度测定。结果2%七氟醚组、3%七氟醚组平台象限停留时间较对照组缩短(P<0.05),穿台次数较对照组减少(P<0.05)。2%七氟醚组、3%七氟醚组凋亡神经元数目较对照组增加(P<0.05)。2%七氟醚组、3%七氟醚组早期凋亡率、晚期凋亡率较对照组增加(P<0.05)。2%七氟醚组、3%七氟醚组荧光强度较对照组增加(P<0.05),钙离子浓度较对照组升高(P<0.05)。结论短时间内吸入1%七氟醚并不会对幼鼠空间学习记忆能力造成影响,短时间吸入2%或者3%七氟醚可降低其空间学习记忆能力,促进海马神经细胞凋亡,提高细胞钙离子浓度可能为触发凋亡的机制。

Objective To observe the influence of inhaling different concentrations of sevoflurane in a short time on spatial learning and memory ability and hippocampal neuronal apoptosis in immature rats.Methods Eighty SD rats aged only one month were selected and divided into control group(2 h of oxygen inhalation),1%sevoflurane group(inhaling 1%sevoflurane for 2 h),2%sevoflurane group(inhaling 2%sevoflurane for 2 h)and 3%sevoflurane group(inhaling 3% sevoflurane for 2 h)by random number table method,with 20 rats in each group.At 12 h after inhalation,5 rats were selected from each group for Morris water maze test.Hippocampal tissues of 5 rats were obtained for hematoxylin-eosin(HE)staining.The neuronal apoptosis in 5 rats was determined by flow cytometry,and the concentration of free calcium ions in the neurons derived from the remaining 5 rats was detected via confocal laser scanning microscopy.Results Compared with the control group,the time spent on traveling in the quadrant where the target platform was located was shorter,and the number of times crossing the target platform was fewer in the 2% sevoflurane group and the 3%sevoflurane group(P<0.05).The number of apoptotic neurons,as well as early apoptotic rate and late apoptotic rate of hippocampal neurons was greater in the 2% sevoflurane group and the 3% sevoflurane group relative to the control group(P<0.05).Besides,fluorescence intensity and concentration of calcium ions in the neurons in the 2% sevoflurane group and 3% sevoflurane group were higher than those in the control group(P<0.05).Conclusions Inhaling 2% or 3% sevoflurane rather than 1% sevoflurane in a short time will dampen the spatial learning and memory ability and promote apoptosis of hippocampal neurons,which may be triggered via the increasing level of calcium ions in the neurons.