大气细颗粒物对胶原结构样巨噬细胞受体基因敲除小鼠呼吸和循环系统的影响

Effect of fine particulate matter on respiratory and cardiovascular systems in mice with macrophage receptor with collagenous structure gene knockout

目的探讨大气细颗粒物(PM_(2.5))对胶原结构样巨噬细胞受体(MARCO)基因敲除小鼠呼吸和循环系统的作用。方法将12只野生型C57BL/6小鼠随机分为野生型生理盐水组和野生型PM_(2.5)组,12只MARCO^(-/-)型C57BL/6小鼠随机分为MARCO^(-/-)型生理盐水组和MARCO^(-/-)型PM_(2.5)组,每组6只。野生型PM_(2.5)组和MARCO^(-/-)型PM_(2.5)组小鼠气管滴注PM_(2.5)混悬液4 mg·kg^(-1),野生型生理盐水组和MARCO^(-/-)型生理盐水组小鼠给予等量无菌生理盐水,隔日1次,共6次。末次滴注24 h后检测各组小鼠支气管肺泡灌洗液(BALF)中肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、乳酸脱氢酶(LDH)及血清中C-反应蛋白(CRP)、TNF-α和LDH水平;免疫组织化学法检测各组小鼠肺组织中磷酸化表皮生长因子受体(EGFR)表达情况。结果野生型生理盐水组与MARCO^(-/-)型生理盐水组小鼠BALF中IL-6、TNF-α、LDH水平及血清中CRP、TNF-α、LDH水平比较差异均无统计学意义(tBALF=-0. 230、-0. 964、1. 263,t血清=-0. 944、-1. 908、-0. 392,P> 0. 05)。野生型PM_(2.5)组与野生型生理盐水组小鼠BALF中IL-6、TNF-α、LDH水平及血清中CRP、TNF-α、LDH水平比较差异无统计学意义(tBALF=-0. 583、-2. 130、-1. 016,t血清=-0. 890、-1. 649、-0. 885,P> 0. 05)。MARCO^(-/-)型PM_(2.5)组小鼠BALF中IL-6、TNF-α、LDH水平及血清中CRP、LDH水平显著高于MARCO^(-/-)型生理盐水组(tBALF=2. 469、3. 364、3. 000,t血清=2. 530、4. 605,P <0. 05),2组小鼠血清TNF-α水平比较差异无统计学意义(t=1. 911,P> 0. 05)。MARCO^(-/-)型PM_(2.5)组与野生型PM_(2.5)组小鼠BALF中IL-6、TNF-α、LDH水平及血清中CRP、TNF-α水平比较差异无统计学意义(tBALF=1. 723、1. 114、-0. 324,t血清=1. 643、1. 311,P> 0. 05);MARCO^(-/-)型PM_(2.5)组小鼠血清LDH水平显著高于野生型PM_(2.5)组(t=2. 378,P <0. 05)。免疫组织化学结果显示,野生型与MARCO^(-/-)型生理盐水组小鼠肺组织中均未见磷酸化EGFR表达,而野生型与MARCO^(-/-)型PM_(2.5)组小鼠肺组织均可见磷酸化EGFR表达,且MARCO^(-/-)型PM_(2.5)组小鼠肺组织中磷酸化EGFR水平高于野生型PM_(2.5)组。结论PM_(2.5)急性暴露可导致MARCO^(-/-)小鼠呼吸和循环系统发生炎性效应,MARCO可能在PM_(2.5)导致的小鼠急性呼吸和循环系统炎症中发挥重要作用。

Objective To investigate the effect of fine particulate matter (PM2.5) on respiratory and cardiovascular systems in mice with macrophage receptor with collagenous structure (MARCO) gene knockout.Methods Twelve wild-type C57BL/6 mice were randomly divided into wide-type normal saline group and wild-type PM 2.5 group,with 6 mice in each group.Twelve MACRO^-/- C57BL/6 mice were randomly divided into MARCO^-/- normal saline group and MARCO^-/- PM2.5 group,with 6 mice in each group.The mice in the wild-type PM2.5 group and MARCO^-/- PM2.5 group were treated with PM2.5 suspension (4 mg·kg^-1) by intratracheal instillation,while the mice in the wide-type normal saline group and MARCO^-/- normal saline group were treated with equal volume of normal saline by intratracheal instillation,once every other day for six times.The levels of tumor necrosis factor-α(TNF-α),interleukin-6 (IL-6),lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid(BALF) and the levels of serum C-reactive protein (CRP),TNF-α,LDH were detected at 24 hours after the last infusion.The expression of phosphorylated epidermal growth factor receptor (EGFR) in lung tissues of mice in each group was determined by immunohistochemistry.Results There was no significant difference in the levels of IL-6,TNF-α,LDH in BALF and the levels of CRP,TNF-α,LDH in serum between the wild-type normal saline group and MARCO^-/- normal saline group (tBALF=-0.230,-0.964,1.263;tserum=-0.944,-1.908,-0.392;P>0.05).There was no significant difference in the levels of IL-6,TNF-α,LDH in BALF and the levels of CRP,TNF-α,LDH in serum between wide-type normal saline group and wild-type PM 2.5 group (tBALF=-0.583,-2.130,-1.016;tserum=-0.890,-1.649,-0.885;P>0.05).The levels of IL-6,TNF-α,LDH in BALF and the levels of CRP,LDH in serum of mice in the MARCO^-/- PM2.5 group were significantly higher than those in the MARCO^-/- normal saline group (tBALF=2.469,3.364,3.000;t serum=2.530,4.605;P<0.05).There was no significant difference in the level of serum TNF-α between the MARCO^-/- PM 2.5 group and MARCO^-/- normal saline group (t=1.911,P>0.05).There was no significant difference in the levels of IL-6,TNF-α,LDH in BALF and the levels of CRP,TNF-α in serum between the MARCO^-/- PM 2.5 group and wild-type PM 2.5 group (tBALF=1.723,1.114,-0.324;tserum= 1.643,1.311;P>0.05).The level of serum LDH of mice in the MARCO^-/- PM 2.5 group was significantly higher than that in the wild-type PM 2.5 group (t=2.378,P<0.05).The immunohistochemical results showed that there was no the expression of phosphorylated EGFR in lung tissues of mice in the wide-type normal saline group and MARCO^-/- normal saline group,while the expression of phosphorylated EGFR was observed in lung tissues of mice in the wild type PM2.5 group and MARCO^-/- PM2.5 group,and the expression of phosphorylated EGFR in lung tissues of mice in the MARCO^-/- PM2.5 group was higher than that in the wild type PM2.5 group.Conclusion The inflammatory reaction of respiratory and cardiovascular systems caused by PM2.5 acute exposure in MARCO^-/- mice is more serious than that in wild type mice.MARCO may play an important role in the acute inflammatory reaction of respiratory and cardiovascular systems of mice caused by PM2.5.