七氟醚对幼鼠海马组织神经元凋亡和γ-氨基丁酸A受体α1/α2亚型组成及远期空间探索能力的影响

The effects of sevoflurane on expression of protein Poly （ADP-ribose） polymerase-1 and γ-aminobutyric acid receptor a1/α2 in hippocampus and the adaptation ability of neonatal rats

目的 通过观察七氟醚对幼鼠海马组织多聚腺苷二磷酸核糖聚合酶-1[Poly（ADP-ribose）polymerase-1,PARP-1]的表达、γ-氨基丁酸A受体（γ-aminobutyric acid subtype A receptor,GABAAR）α1/α2亚型组成及空间探索认知能力的影响,分析七氟醚对发育神经元的毒性作用及可能的相关机制.方法 选取出生后7d的SD幼鼠216只,设定0.8 MAC（2.11％）浓度七氟醚维持时间4h作为麻醉处理条件.利用随机数字表法将幼鼠分为对照组（A组）、假麻醉组（B组）和麻醉组（C组）,每组72只.经不同处理后3组分别于6、24、72 h各取6只幼鼠海马组织进行Western blot检测,确定PARP-1.再以同样方法、数量检测GABAARα1亚型和α2亚型水平,观察GABAAR α1/α2亚型组成与神经元凋亡的关联.3组分别在幼鼠成长至5、8、14周时随机选12只进行旷场实验.结果 与A组（100％）比较,C组于麻醉后6 h PARP-1表达水平明显增加[（216±15）％]（P＜0.05）,而与A组（100％）比较,GABAAR α1/α2蛋白含量比值于麻醉结束后6 h[（126±6）％]、24 h[（127±8）％]及72 h[（183±22）％]均不同程度升高（P＜0.05）.B组各检测指标与A组比较差异无统计学意义（P＞0.05）.5周时接受七氟醚麻醉的幼鼠（C组）在旷场中平面活动及垂直活动均多于A组,B组各观察指标与A组比较差异无统计学意义（P＞0.05）.8周和14周时,各组动物旷场表现差异无统计学意义（P＞0.05）.结论 七氟醚可引起早期的细胞死亡,且其神经毒性作用与受体的影响有关,可引起GABAARα1/α2比值增加,α2亚型向α1亚型进行转化.七氟醚可引起成长中幼鼠在陌生环境中的活动增加,影响其短期内对新环境的适应能力及空间探索认知能力.

Objective To investigate the effect of sevoflurane on the expression of poly （ADP-ribose） polymerase-1（PARP-1） protein and γ-aminobutyric acid subtype A receptor （GABAAR） α1/α2 in hippocampus, and analyze its possible neurotoxicity mechanisms in the developing brain of rats.Methods Two hundred and sixteen neonatal SD rats （7 d postnatal, P7） were randomly divided into three groups（n=72）： the control group（group A）, the sham anesthesia group（group B）, and the anesthesia group（group C）.The anesthesia management was a 4-hour exposure to the 0.8 MAC （2.11%） sevoflurane.The expression of the PARP-1 and GABAAR α1/α2 in the hippocampus was examined by western blotting at 6, 24, 72 h after anesthesia, respectively.Open-field test were then performed separately when the rats were 5, 8, 14-week-old, respectively.Results Compared with group A（100%）, the expression of the PARA-1 was significantly increased at 6 h after sevoflurane exposure in group C [（216±15）%, P〈0.05], and the ratio of α1/α2 subgroup of GABAAR was significantly increased at 6 h [（126±6）%], 24 h [（127±8）%], and 72 h [（183±22）%] after sevoflurane exposure （P〈0.05）.Both the expression of PARP-1 and the ratio of α1/α2 subgroup of GABAAR was of no significant difference between group A and group B.Rats exposed to sevoflurane （group C） showed a longer travel distance and time than that in group A underwent open-f ield test when they were 5 weeks old （P〈0.05）, and there was no significant difference in the activities between group A and group B （P〉0.05）.While no differences were seen in the activities when rats were 8 and 14 weeks old（P〉0.05）.Conclusions The exposure of sevoflurane can induce the apoptosis of neurons at early stage, indicated by the α1/α2 subgroup of GABAAR increasing.Sevoflurane might affect the adaptation and cognition ability of environment in the short term in neonatal rats.