背景:肺炎后的急性肺损伤(ALI)涉及不受控制的炎症和组织损伤,导致高死亡率。我们先前证实了与初始和其他预处理方法相比,凝血酶预处理的人间充质基质细胞(thMSC)中的货物含量和细胞外囊泡(EV)产生显着增加。本研究旨在研究源自thMSCs的EVs在大肠杆菌(E.大肠杆菌)诱导的ALI小鼠模型。
方法:体外,用0.1μg/mL脂多糖(LPS)刺激RAW264.7细胞1小时,然后用PBS(LPSCtrl)或5×107颗粒的thMSC-EV(LPS+thMSC-EV)处理24小时。收获细胞和培养基用于流式细胞术和ELISA。在体内,将ICR小鼠麻醉,插管,施用2×107CFU/100μl大肠杆菌。50分钟后,然后给小鼠施用50μL盐水(ECS)或1×109颗粒/50μLthMSC-EV(EME).三天后,使用提取的肺组织评估thMSC-EVs的疗效,支气管肺泡灌洗液(BALF),和体内计算机断层扫描。采用单因素方差分析和事后TUKEY检验对实验组进行统计学比较。
结果:体外,IL-1β,LPS+thMSC-EV组的CCL-2和MMP-9水平显著低于LPSCtrl组。正常对照中M1巨噬细胞的百分比,LPSCtrl,LPS+thMSC-EV组为12.5、98.4和65.9%,分别。在体内,EME组肺泡充血的组织学评分明显降低,出血,壁厚,和白细胞浸润高于ECS组。EME组的肺干湿比显着低于ECS组。BALF中CCL2、TNF-a、EME组的IL-6水平明显低于ECS组。体内CT分析显示,EME组受损肺的百分比明显低于ECS组。
结论:气管内给予MSC-EV可显著减少大肠杆菌诱导的炎症和肺组织损伤。总的来说,这些结果表明,治疗增强的thMSC-EV是ARDS/ALI的一种新的有前景的治疗选择.
BACKGROUND: Acute lung injury (ALI) following pneumonia involves uncontrolled inflammation and tissue injury, leading to high mortality. We previously confirmed the significantly increased cargo content and extracellular vesicle (EV) production in
thrombin-preconditioned human mesenchymal stromal cells (thMSCs) compared to those in naïve and other preconditioning methods. This study aimed to investigate the therapeutic efficacy of EVs derived from thMSCs in protecting against inflammation and tissue injury in an Escherichia coli (E. coli)-induced ALI mouse model.
METHODS: In vitro, RAW 264.7 cells were stimulated with 0.1 µg/mL liposaccharides (LPS) for 1 h, then were treated with either PBS (LPS Ctrl) or 5 × 107 particles of thMSC-EVs (LPS + thMSC-EVs) for 24 h. Cells and media were harvested for flow cytometry and ELISA. In vivo, ICR mice were anesthetized, intubated, administered 2 × 107 CFU/100 µl of E. coli. 50 min after, mice were then either administered 50 µL saline (ECS) or 1 × 109 particles/50 µL of thMSC-EVs (EME). Three days later, the therapeutic efficacy of thMSC-EVs was assessed using extracted lung tissue, bronchoalveolar lavage fluid (BALF), and in vivo computed tomography scans. One-way analysis of variance with post-hoc TUKEY test was used to compare the experimental groups statistically.
RESULTS: In vitro, IL-1β, CCL-2, and MMP-9 levels were significantly lower in the LPS + thMSC-EVs group than in the LPS Ctrl group. The percentages of M1 macrophages in the normal control, LPS Ctrl, and LPS + thMSC-EV groups were 12.5, 98.4, and 65.9%, respectively. In vivo, the EME group exhibited significantly lower histological scores for alveolar congestion, hemorrhage, wall thickening, and leukocyte infiltration than the ECS group. The wet-dry ratio for the lungs was significantly lower in the EME group than in the ECS group. The BALF levels of CCL2, TNF-a, and IL-6 were significantly lower in the EME group than in the ECS group. In vivo CT analysis revealed a significantly lower percentage of damaged lungs in the EME group than in the ECS group.
CONCLUSIONS: Intratracheal thMSC-EVs administration significantly reduced E. coli-induced inflammation and lung tissue damage. Overall, these results suggest therapeutically enhanced thMSC-EVs as a novel promising therapeutic option for ARDS/ALI.