目的：观察微清蛋白(parvalbumin,PV)在七氟醚麻醉致小鼠认知功能损害中的表达变化,并研究丰富环境是否能改善此种变化。方法6日龄新生雄性 C57BL/6小鼠144只随机均分为四组(n =36)：对照+标准环境组(CS 组)、对照+丰富环境组(CE 组)、七氟醚+标准环境组(SS组)及七氟醚+丰富环境组(SE 组)。SS 及 SE 组分别在出生后第6、7、8天每天接受1次2 h 的3%七氟醚麻醉+30%氧气；CS 及 CE 组在相应日龄吸入30%氧气。从 P8到 P90,CE 及 SE 组小鼠每天接受2 h 丰富环境饲养,CS 及 SS 组则在标准环境下饲养。小鼠于 P42行旷场实验,于 P42-43和P89-90分别行场景条件性恐惧实验。并于 P9、P14、P42、P60及 P90取小鼠皮层及海马组织,采用Western blot 检测小鼠额叶皮层及海马中微清蛋白的表达。结果旷场实验测试中,四组探索路程和中央格停留时间差异无统计学意义。场景性恐惧实验测试中,SS 组 P43僵直反应时间百分比明显低于 CS 组(P <0.05),但在 P90差异无统计学意义；在 P9和 P14,SS 组前额皮层及海马中 PV 表达明显低于 CS 组(P <0.01),但在 P60、P90恢复正常；在 P42,SE 组前额皮层及海马中 PV 表达明显高于 SS 组(P <0.05)；线性回归分析表明：小鼠前额皮层中 PV 表达量与环境诱导僵直时间成显著正相关(r =0.6707,P =0.0001),小鼠海马中 PV 表达量与环境诱导僵直时间成显著正相关(r =0.5096,P =0.0019)。结论七氟醚暴露(P6-P8)可致小鼠认知功能损伤伴随前额皮层和海马 PV表达降低,丰富环境可减轻此种损伤。%Objective To investigate the expression of parvalbumin (PV)in the cognitive im-pairment mice induced by sevoflurane anesthesia,and to explore whether enriched environment could reverse it.Methods One hundred and forty-four Six-day-old C57BL/6 male mice at postnatal day 6 were randomly divided into the following four groups (n =36):control+standard environment group (group CS),control+enriched environment group(group CE),sevoflurane anesthesia+standard en-vironment group(group SS)and sevoflurane anesthesia+enriched environment group(group SE).An-imals were exposed to 3% sevoflurane plus 30% O 2 or 30% O 2 2 h daily for 3 days from postnatal day 6 (P6)to P8.The exposed pups were randomly allocated to an enriched environment for 2 h daily between P8 and P90 or to a standard environment.Western blotting were used for determining PV ex-pression in the prefrontal cortex and hippocampus at P9,P14,P42,P60 and P90.Cognitive functions were assessed by performing the open field (P41 ),and fear conditioning tests (P42-43 and P89-90, respectively).Results In the open field test,there was no significant difference in the total travel dis-tance and the time spent in the center of the arena among groups.In the contextual fear condition test, compared with group CS,the group SS only exhibited a reduced freezing response in the contextual test at P43,but not at P90.In the cued fear conditioning test,no difference was observed in the freez-ing time among the four groups.The PV expression in the prefrontal cortex and hippocampus of group SS were significantly lower than that of group CS at P9 and P14 (P <0.001),while recovered at P60 and P90.The PV expression in the prefrontal cortex and hippocampus of group SE were significantly higher than that of group SS at P42 (P <0.05).Linear regression analysis demonstrated a positive correlation between the PV expression in the prefrontal cortex and the freezing time induced by envi-ronment (r =0.670 7,P =0.000 1),and there was a positive correlation between the PV expression in hippocampus and the freezing time induced by environment (r = 0.509 6,P = 0.001 9 ). Conclusion The cognitive impairment induced by sevoflurane anesthesia may be associated with the reduction of PV in the prefrontal cortex and hippocampus.Placement of the sevoflurane-exposed mice in an enriched environment prevented the development of these abnormalities.
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