持续光照与苯暴露对小鼠红细胞参数和miRNA-144/451簇表达的影响

Influence of continuous light and benzene exposure on erythrocyte parameters and expression of miRNA-144/451 in mice

目的观察持续光照与苯暴露对小鼠周围血红细胞相关参数和骨髓组织miR-144/451表达的影响。方法采用2×2析因设计,光照周期因素设正常光照和持续光照水平,分别予光照/黑暗12 h/12 h和24 h光照处理;苯暴露因素设非暴露和暴露水平,分别予质量浓度为0.0和32.5 mg/m^(3)的苯静式吸入染毒,3 h/d,5 d/周,共4周。据此将无特定病原体雄性C57BL/6 J小鼠随机分为阴性对照组、单纯持续光照组、单纯苯暴露组和联合暴露组,每组12只。染毒结束后,分4个时段采集小鼠周围血检测红细胞相关参数;处死小鼠后采集骨髓组织,采用实时荧光定量聚合酶链式反应法检测miR-451a和miR-144-5p的表达。结果小鼠周围血红细胞比容(HCT)、平均红细胞体积、平均血红蛋白浓度(MCHC)、平均红细胞血红蛋白含量和骨髓组织miR-451a相对表达水平均仅在苯暴露的主效应上有统计学意义(P值均<0.05);其中,与非苯暴露小鼠比较,苯暴露小鼠除MCHC升高(P<0.05)外,其余4个指标均下降(P值均<0.05)。阴性对照组小鼠周围血红细胞计数、血红蛋白水平和HCT均呈节律性(P_(节律)值均<0.05);而单纯持续光照组和联合暴露组小鼠上述指标均呈失节律(P_(节律)值均>0.05),单纯苯暴露组小鼠周围血血红蛋白水平和HCT亦呈失节律(P_(节律)值均>0.05)。阴性对照组和单纯持续光照组小鼠骨髓组织miR-451a相对表达水平均呈节律性(P_(节律)值均<0.05),而单纯苯暴露组和联合暴露组小鼠该指标的表达均呈失节律(P_(节律)值均>0.05)。结论苯暴露导致小鼠红细胞参数的改变是独立作用;其机制可能与骨髓组织miR-451a的节律性表达紊乱有关。持续光照和苯暴露及其交互作用均可在某种程度上干扰红细胞计数、血红蛋白和HCT等红细胞参数的昼夜节律性。

Objective To explore the effects of continuous light and benzene exposure on peripheral blood erythrocyte parameters and expression of miR-144/451 in the bone marrow of mice.Methods This was a 2×2 factorial design.Photoperiod factor was set as normal and continuous light levels,and mice were treated for 12 hours/12 hours light/dark or 24 hours light,respectively.The benzene exposure factor was set as non-exposure and exposure levels.Mice were exposed to benzene by static inhalation with a mass concentration of 0.0 and 32.5 mg/m^(3)for three hours per day,five days per week for a total of four weeks.Specific pathogen free male C57BL/6 J mice were randomly divided into negative control group,simple continuous light group,simple benzene-exposure group and combined-exposure group,with 12 mice per group.After benzene exposure,peripheral blood was collected for the detection of erythrocyte parameters in four periods.After the mice were sacrificed,the expression of miR-451a and miR-144-5p was detected by real-time fluorescence quantitative polymerase chain reaction in bone marrow tissues.Results The hematocrit volume(HCT),mean corpuscular volume,mean corpuscular hemoglobin concentration(MCHC)and mean corpuscular hemoglobin in peripheral blood and the relative expression of miR-451a in bone marrow tissue were statistically significant only in mice with benzene exposure(all P<0.05).Among them,the MCHC of benzene exposed mice increased(P<0.05),but the other four indexes decreased(all P<0.05)compared with non-benzene exposed mice.In the negative control group,the change of red blood cells count,hemoglobin level and HCT in peripheral blood were rhythmical(all P_(rhythmical)<0.05).However,the indexes above were out of rhythm(all P_(rhythmical)>0.05)in the simple continuous light group and the combined-exposure group.The change of hemoglobin level and HCT of peripheral blood were also out of rhythm(all P_(rhythmical)>0.05)in the simple benzene-exposure group.The relative expression of miR-451a in bone marrow tissues of negative control group and simple continuous light group was rhythmical(all P_(rhythmical)<0.05),while the relative expression of miR-451a in simple benzene-exposure group and combined-exposure group was out of rhythm(all P_(rhythmical)>0.05).Conclusion Benzene exposure induced changes in erythrocyte parameters of mice are independent effect,and its mechanism may be related to the rhythmic expression disorder of miR-451a in bone marrow tissues.Continuous light,exposure benzene exposure and their interactions can interfere with the circadian rhythm of erythrocyte parameters such as red blood cell count,hemoglobin and HCT to some extent.