■创伤,一个重要的全球死亡和残疾原因,常导致骨折和失血性休克,引发过度的炎症反应,伤害远处的器官,尤其是肺。老年人在创伤后更容易受到免疫失调的影响,导致器官损伤加剧,感染,和不良的健康结果。本研究探讨NF-κB和炎性小体在老年小鼠创伤后肺损伤中的作用。
■十二只雄性C57BL/6J小鼠经历了失血性休克和股骨骨折(截骨术)并带有外固定(Fx)(创伤/出血,THFx),而另外12人接受了假手术。包括来自年轻(17-26周)和老年(64-72周)组(n=6)的小鼠。24h后,通过苏木精-伊红染色评估肺损伤,原表面活性剂蛋白C(SPC)水平,HMGB1和Muc5acqRT-PCR。Nlrp3和IL-1β的基因表达,测定肺组织和支气管肺泡灌洗液中IL-6和IL-1β蛋白水平。肺浸润的多形核白细胞(PMNL)和活化的caspase-3表达水平评估细胞凋亡,以及NLRP3,ASC,通过免疫染色分析和GasderminD(GSDMD)评估炎症小体成分的表达。为了研究NF-κB信号的作用,蛋白质印迹法测定磷酸化和非磷酸化p50蛋白表达。
■Muc5ac,和SPC作为肺保护蛋白,THFx与假手术相比显著下降。与THFx-young相比,THFx-老化表现出显著较低的SPC和较高的HMGB1水平。与两个假手术组相比,THFx显著增加了活化的caspase-3,与THFx-young相比,THFx年龄的caspase-3阳性细胞明显更多。与相应的年轻组相比,假手术组和THFx年龄组的IL-6均显着增加。与相应的假手术组相比,THFx在两组中均显着增强了PMNL。与THFx年轻相比,THFx年龄的这种增加进一步加剧。p50和磷酸化p50的表达在所有老年组增加,与THFx年轻相比,THFx诱导的p50磷酸化在THFx年龄中显着增加。THFx增加炎症小体标志物IL-1β的表达,NLRP3,ASC和GSDMD与假,衰老进一步显著放大了这些变化。
■这项研究的结果表明,衰老过程加剧了创伤后过度的炎症反应和对肺的损害。潜在的机制与NF-κB的激活增强和炎性小体成分的表达增加有关。
Trauma, a significant global cause of mortality and disability, often leads to fractures and hemorrhagic shock, initiating an exaggerated inflammatory response, which harms distant organs, particularly the lungs. Elderly individuals are more vulnerable to immune dysregulation post-trauma, leading to heightened organ damage, infections, and poor health outcomes. This study investigates the role of NF-κB and inflammasomes in lung damage among aged mice post-trauma.
Twelve male C57BL/6J mice underwent hemorrhagic shock and a femoral fracture (osteotomy) with external fixation (Fx) (trauma/hemorrhage, THFx), while another 12 underwent sham procedures. Mice from young (17-26 weeks) and aged (64-72 weeks) groups (n=6) were included. After 24h, lung injury was assessed by hematoxylin-eosin staining, prosurfactant protein C (SPC) levels, HMGB1, and Muc5ac qRT-PCR. Gene expression of Nlrp3 and Il-1β, and protein levels of IL-6 and IL-1β in lung tissue and bronchoalveolar lavage fluid were determined. Levels of lung-infiltrating polymorphonuclear leukocytes (PMNL) and activated caspase-3 expression to assess apoptosis, as well as NLRP3, ASC, and Gasdermin D (GSDMD) to assess the expression of inflammasome components were analyzed via immunostaining. To investigate the role of NF-κB signaling, protein expression of phosphorylated and non-phosphorylated p50 were determined by western blot.
Muc5ac, and SPC as lung protective proteins, significantly declined in THFx versus sham. THFx-aged exhibited significantly lower SPC and higher HMGB1 levels versus THFx-young. THFx significantly increased activated caspase-3 versus both sham groups, and THFx-aged had significantly more caspase-3 positive cells versus THFx-young. IL-6 significantly increased in both sham and THFx-aged groups versus corresponding young groups. THFx significantly enhanced PMNL in both groups versus corresponding sham groups. This increase was further heightened in THFx-aged versus THFx-young. Expression of p50 and phosphorylated p50 increased in all aged groups, and THFx-induced p50 phosphorylation significantly increased in THFx-aged versus THFx-young. THFx increased the expression of inflammasome markers IL-1β, NLRP3, ASC and GSDMD versus sham, and aging further amplified these changes significantly.
This study\'s findings suggest that the aging process exacerbates the excessive inflammatory response and damage to the lung following trauma. The underlying mechanisms are associated with enhanced activation of NF-κB and increased expression of inflammasome components.