七氟烷不同吸入浓度与时间对新生大鼠认知功能及海马脑源性神经营养因子表达的远期影响

摘要

目的 评价七氟烷不同吸入浓度与时间对新生大鼠认知功能和海马脑源性神经营养因子(brain derived neurotrophic factor,BDNF)表达的远期影响.方法 7d龄SD大鼠采用随机数字表法随机分为4组(每组20只):空白对照组(C组)、5.1％七氟烷1.3 h组(S组)、3.4％七氟烷2h组(M组)和1.7％七氟烷4h组(L组).麻醉后21 d进行旷场实验和新异物体识别实验,随后采取免疫组织化学和逆转录-聚合酶链反应(reverse transcriptive polymerase chain reaction,RT-PCR)技术,分别检测各组大鼠海马BDNF和BDNF mRNA的表达.结果 ①各项检测均发现S组与对照组差异无统计学意义(P＞0.05)；②旷场实验发现M组与对照组差异无统计学意义；新异物体识别实验中M组在第24小时的探究新物体时间所占比值为63.4％,明显低于对照组69.8％(P＜0.05)；海马区BDNF平均光密度值和BDNF mRNA的相对表达量分别为0.229±0.021与0.775±0.024,分别低于对照组的0.251 ±0.020与0.799±0.023(P＜0.05).③行为学测试与BDNF和BDNF mRNA检测显示,L组大鼠的各项指标与对照组差异有统计学意义(P＜0.05),同M组相比差异也具有统计学意义(P＜0.05).结论 七氟烷可能导致新生大鼠远期的认知功能下降,其中时间因素影响较大,可能与海马部位BDNF表达下降有关.%Objective To investigate the long-term effects of sevoflurane given by different concentration and time course on cognitive function and expression of hippocampus brain derived neurotrophic factor(BDNF)in neonatal rats.Methods SD rats at seven-day-old were randomly divided into 4 groups.Rats only inhaled oxygen as control(group C)or inhaled sevoflurane at 5.1％ for 1.3 h(group S),at 3.4％ for 2 h(group M)and at 1.7％ for 4 h(group L).Each group has 20 rats.Open field test and novel obiect recognition test were used to assess the cognitive function of the rats at 28-day-old.Then these rats were killed and measurede the expressions of BDNF and BDNF mRNA using immuno-histochemistry and reverse transcriptive polymerase chain reaction(RT-PCR)in hippocampus respectively.Results ① In all tests,there was no significant change between group S and group C(P＞0.05).② Group M didn't not exhibit significant difference in comparison with group C in every item of the open field test.In the novel obiect recognition test,the percentage of exploring time on new object of group M in 24th hour was 63.4％,which showed significantly lower than controls 69.8％(P＜0.05).The average optic density of BDNF(0.229±0.021)and the relative value of BDNF mRNA(0.775±0.024)of hippocampus of group M were both lower than(0.0251 ±0.020)and(0.799±0.023)of control C respectivly(P＜0.05).③ No matter the tests of cognitive function or expressions of BDNF and BDNF mRNA,each index of group L was worse than group C and group M (P＜0.05).Conclusion sevoflurane can induce forward cognitive decline in neonate rat,that may be because of decreasing the expression of BDNF in hippocampus.The time of inhaleing sevoflurane was an important reason.