弥散富氧对高原颅脑损伤小鼠行为学及海马CA1区的影响

Effects of diffuse oxygen enrichment on the behavior and hippocampal CA1 area of mice with traumatic brain injury at high altitude

目的:探索低压低氧环境下弥散富氧对颅脑损伤小鼠的行为学以及海马CA1区的影响。方法:利用低压低氧舱模拟海拔6000 m环境,利用便携式膜法氧气机与IVC笼构建弥散富氧笼。将21只雄性C57小鼠随机分为颅脑损伤(TBI)平原组(Sham组)、TBI低氧组(TLO组)和TBI富氧组(THO组)。TLO组与THO组置于模拟舱内饲养1周(24 h/d),THO组每天24 h富氧30%±3%(V/V),Sham组置于当地海拔约400 m同时饲养。1周后,对小鼠体质量、行为学指标进行测量,并观察海马体结构。结果:实验前各组小鼠体质量无统计学差异(P>0.05);实验后TLO组与THO组体质量显著降低(P<0.05),且THO组较TLO组小鼠体质量显著上升(P<0.05)。与Sham组相比,TLO组垂直活跃度显著降低(P<0.05);与TLO组相比,THO组水平活跃度及垂直活跃度显著增强(P<0.05)。TLO组海马锥体细胞胞核体积缩小,染色加深;THO组海马锥体细胞结构损伤显著减轻,排列相对整齐。结论:模拟海拔6000 m进行弥散富氧干预可有效减轻高原TBI小鼠海马损伤,降低其烦躁和焦虑程度,提高空间探索能力。

Objective To explore the effects of diffuse oxygen enrichment on the ethology and the hippocampus CA1 area of mice with traumatic brain injury(TBI)in hypobaric hypoxia.Methods The hypobaric hypoxic chamber was used to simulate the special environment of high altitude at 6000 m,while the portable membrane oxygen enricher and IVC cage were used to construct a diffuse oxygen-enriched cage.Twenty-one male C57 mice were randomly divided into TBI plain group(Sham group),TBI hypoxia group(TLO group)and TBI oxygen enrichment group(THO group).The mice in TLO group and THO group were placed in the simulated chamber for 1 week(24 h/d);and those in THO group were enriched with oxygen for 24 h every day(30%±3%,V/V).The mice in Sham group were raised at the local altitude(about 400 m).After a week of experiment,the body weight and behavioral indexes of the mice were measured,and the structure of the hippocampus was also observed.Results There was no significant difference in body weight among 3 groups before the experiment(P>0.05).After the experiment,the mice in both TLO group and THO group had significantly lower body weight than those in Sham group(P<0.05),and the body weight of the mice in THO group was significantly higher than that of the mice in TLO group(P<0.05).Moreover,the vertical activity of the mice in TLO group was significantly inferior to that of the mice in Sham group(P<0.05);and compared with those of the mice in TLO group,the horizontal activity and vertical activity of the mice in THO group were significantly increased(P<0.05).In TLO group,the nuclei of hippocampal pyramidal cells were shrinked in volume,and the staining was deepened.However,the structural damage of hippocampal pyramidal cells in THO group was significantly alleviated,and the arrangement was relatively neat.Conclusion The diffuse oxygen enrichment can effectively prevent TBI mice at high altitude from hippocampal damages,reduce their irritability and anxiety and improve their capability for space exploration.