不同浓度氧暴露对早产儿外周血单个核细胞SIRT1通路的影响

摘要

Objective To observe the effects of exposure to different concentrations of oxygen at different time points on expression changes of SIRT1 pathway-related protein in peripheral blood mononuclear cells (PBMCs) of preterm infants with low body mass and to investigate the mechanism of oxidative stress injury induced by oxygen exposure.Methods Eighty cases of premature infants with low body mass,who were diagnosed with neonatal respiratory distress syndrome at admission and needed immediate oxygen therapy,were selected.According to the concentrations of oxygen inhalation,we divided them into the control group,low-concentration oxygen group,medium-concentration oxygen group,and high-concentration oxygen group,with 20 cases in each group.In the control group,the oxygen concentration (FiO2) was 21% or more than 21%,but the total oxygen time was less than 24 h.In the low-concentration oxygen group,FiO2 was more than 21%,and the total oxygen time was more than 24 h,or according to the patients′ condition the total oxygen time was less than 24 h with with FiO2>30%.In the medium-concentration oxygen group,FiO2 was from more than 30% to less than 40%,and the total oxygen time was more than 24 h,or according to the patients′ condition the total oxygen time was less than 24 h with FiO2>40%.In the high-concentration oxygen group,FiO2 was 40% or more than 40%,but the total oxygen time was more than 24 h.PBMCs were isolated from the peripheral blood samples (2 mL) collected from radial artery at day 0,7,14,and 28 after birth.SIRT1 localization was detected by immunofluorescence.The expression of SIRT1 protein,silent mating type information regulation 2 homolog-1 (SENP1) protein and acetylated p53 protein was detected in PBMCs by Western blotting.Results Compared with the control group,the reactive oxygen species (ROS) content in PBMCs increased gradually (P<0.05),the SIRT1 translocation rate increased gradually (P<0.05),the SIRT1 protein level in nucleus decreased significantly (P<0.05),the the SENP1 protein level in PBMCs increased (P<0.05),and the level of acetylated p53 protein in PBMCs increased (P<0.05) with the increase of oxygen concentration and prolonged hospital stay.Conclusion High concentrations of oxygen exposure and prolonged oxygen therapy can lead to large amounts of ROS produced by PBMCs in preterm infants with low body mass,and this mechanism may be related with the oxidative stress injury caused by the increased expression of SENP1 protein,the increased SIRT1 nuclear translocation and acetylation of p53 in PBMCs.%目的 观察不同浓度及不同时间氧暴露对低体质量早产儿外周血单个核细胞(PBMCs)内沉默信息调节因子2相关酶1(SIRT1)通路相关蛋白表达的影响,探讨氧暴露导致氧化应激损伤的机制.方法 选取低体质量早产儿80例,入院时诊断为新生儿呼吸窘迫综合征且需要立即氧疗.根据吸氧浓度分为对照组、低浓度吸氧组、中浓度吸氧组、高浓度吸氧组各20例.对照组吸氧浓度FiO=21%或以FiO2>21%吸氧,但总吸氧时间<24 h;低浓度吸氧组FiO2>21%,吸氧时间>24 h,或因病情需要FiO2>30%的吸氧时间<24 h;中浓度吸氧组FiO2为30%~<40%,吸氧时间>24 h,或因病情需要FiO2>40%的吸氧时间<24 h;高浓度吸氧组为FiO2≥40%且吸氧时间>24 h.分别于生后0、7、14、28 d时,均经桡动脉采血2 mL,分离PBMCs.采用激光共聚焦显微镜技术检测PBMCs中活性氧簇(ROS)水平并进行SIRT1定位检测.采用Western blot法检测PBMCs内胞核SIRT1蛋白及PBMCs内SUMO特异性蛋白酶1(SENP1)、乙酰化p53蛋白表达.结果 随着吸氧浓度的增加,生后住院时间的延长,与对照组相比,PBMCs内的ROS含量逐渐增加(P<0.05),SIRT1转位率逐渐增加(P<0.05),胞核SIRT1蛋白水平明显降低,PBMCs内SENP1蛋白水平增加(P<0.05),乙酰化p53蛋白水平增加(P<0.05).结论 高浓度的氧暴露及长时间的氧疗时间可导致低体质量早产儿PBMCs中产生大量的ROS,其机制可能与PBMCs中SENP1蛋白表达增加、SIRT1核转位、乙酰化p53增高导致的氧化应激损伤有关.