目的:探讨半乳凝集素3(Ga13)在小鼠肺缺血再灌注损伤(LIRI)模型中的表达情况.方法:将20只C57BL/6J雄性小鼠随机分为假手术组和4个实验组(即LIRI后2 h组、LIRI后6 h组、LIRI后12 h组、LIRI后24 h组),每组4只.假手术组只开胸不夹闭肺门,实验组夹闭肺门60min并分别于松开血管夹后2h、6h、12h、24h收集左肺标本.采用苏木精—伊红(HE)染色法和肺组织湿干重比(W/D)观察肺组织病理学变化,酶联免疫吸附法(ELISA)检测支气管肺泡灌洗液(BALF)炎性因子白细胞介素-1β(IL-1β)和肿瘤坏死因子α(TNF-a)的表达,分别采用实时荧光定量PCR(RT-qPCR)、western blotting、免疫荧光染色法检测Gal3 mRNA与Ga13蛋白的表达水平.结果:与假手术组相比,LIRI后各实验组出现肺组织损伤,组织结构破坏明显,肺损伤评分和W/D均升高,炎症因子IL-1β和TNF-a水平升高(均P＜0.05),在LIRI后6h肺组织病理学损伤程度和炎性因子水平达到峰值(P＜0.05),随后逐渐降低.与假手术组相比,LIRI后各实验组Ga13 mRNA及其蛋白表达水平升高,Ga13免疫荧光染色表达水平升高(P＜0.05),均于LIRI后6 h达到高峰(P＜0.05),然后逐渐下降.结论:小鼠LIRI后Ga13表达升高,高水平的Ga13可能与LIRI后的肺组织损伤和炎症爆发有关.

Lung ischemia-reperfusion injury (LIRI) is a severe multifaceted pathological condition that can lead to poor patient outcome where oxidative stress and the resulting inflammatory response can trigger and exacerbate tissue damage in LIRI patients. Sirtuin3 (SIRT3), a member of the sirtuin family, protects against oxidative stress-related diseases. However, it remains unclear if and how SIRT3 alleviates lung injury induced by ischemia/reperfusion (I/R). Our previous study showed that lung tissue structures were severely damaged at 6 h after lung I/R in mice, however, repair of the injured lung tissue was significant at 24 h. In this study, we found that both SIRT3 mRNA and protein levels were markedly increased at 24 h after lung I/R in vivo. Meanwhile, inhibition of SIRT3 aggravated lung injury and inflammation, augmented mitochondrial fission and oxidative stress and increased Hypoxia-inducible factor-1α (HIF-1α) expression in vivo. The results suggest that SIRT3 may be an upstream regulator of HIF-1α expression. Knockdown of SIRT3 resulted in excessive mitochondrial fission and increased oxidative stress in vitro, and we found that knocking down the expression of HIF-1α alleviated these changes. This suggests that the SIRT3-HIF-1α signaling pathway is involved in regulating mitochondrial function and oxidative stress. Furthermore, inhibition of dynamin-related protein 1 (Drp-1) by the inhibitor of mitophagy, Mdivi-1, blocked mitochondrial fission and alleviated oxidative stress in vitro. Taken together, our results demonstrated that downregulation of SIRT3 aggravates LIRI by increasing mitochondrial fission and oxidative stress. Activation of SIRT3 inhibits mitochondrial fission and this mechanism may serve as a new therapeutic strategy to treat LIRI.

Lung ischemia reperfusion injury (LIRI) is a complex pathophysiological process with high morbidity and mortality. An important pathophysiological characteristic of LIRI is endothelial barrier dysfunction, although the mechanism involved in this process remains unclear. VX765, a specific caspase-1 inhibitor, has been shown to have a protective effect against several diseases including sepsis, atherosclerosis, and glial inflammatory disease. The objective of this study was to determine whether VX765 had a protective effect in LIRI. The results showed that lung ischemia/reperfusion (I/R) and oxygen/glucose deprivation and reoxygenation (OGD/R) induced endothelial pyroptosis and barrier dysfunction characterized by an inflammatory response. Treatment with VX765 successfully alleviated I/R- and OGD/R-induced endothelial pyroptosis and barrier dysfunction by inhibiting caspase-1 in vivo and in vitro. In conclusion, these findings showed that VX765 provided effective protection against lung I/R-induced endothelial pyroptosis and barrier dysfunction.

目的:探讨热休克蛋白60(HSP60)调控2型髓系细胞触发受体(TREM2)对肺缺血再灌注损伤(LIRI)小鼠的保护作用.方法:将24只C57BL/6小鼠随机分成对照组、HSP60组、LIRI组、LIRI+HSP60组,每组6只.LIRI+HSP60组于术前1 h腹腔注射HSP60(5 μg/g).HSP60组腹腔注射等剂量的HSP60;对照组不做任何处理.LIRI组和LIRI+HSP60组小鼠建立LIRI模型,术后6 h收集左肺组织标本,苏木精—伊红(HE)染色法观察肺组织病理学变化,透视电镜观察肺组织超微结构改变,酶联免疫吸附法(ELISA)检测肺组织中炎性因子白细胞介素-1β(IL-1β)、白细胞介素-18(IL-18)的表达,实时荧光定量PCR(qPCR)法与Western blotting检测TREM2 mRNA及TREM2蛋白的相对表达水平.结果:与对照组和HSP60组比较,LIRI组肺组织损伤严重,肺组织结构改变明显,肺损伤评分明显增加(P＜0.05),炎症因子IL-1β和IL-18水平均明显升高(均P＜0.05),TREM2 mRNA及其蛋白相对表达水平均明显降低(均P＜0.05).与LIRI组比较,LIRI+HSP60组肺组织病理学损伤明显改善,肺损伤评分明显降低(P＜0.05),炎症因子IL-1β和IL-18表达明显减少(均PP＜0.05),TREMM2 mRNA及其蛋白的相对表达水平均明显升高(均P＜0.05).与对照组相比较,HSP60组TREM2mRNA及蛋白的相对表达水平均明显升高(P＜0.05).结论:HSP60可以减轻LIRI,其机制可能与上调TREM2的表达有关.

Objective:To investigate the role and regulatory mechanism of triggering receptor expressed on myeloid cell 2 (TREM2) in mice lung ischemia/reperfusion injury (LIRI).Methods:Thirty-six healthy male C57BL/6 mice were divided into six groups according to the random number method ( n = 6): normal control group, and LIRI 2, 6, 12, 24, 48 hours group. Mice LIRI models were established by clamping the left hilum. The wet/dry weight ratio (W/D) of left lung tissue was measured. Lung injury was observed and evaluated by hematoxylin-eosin (HE) staining and electron microscopy. The levels of interleukins (IL-1β, IL-18) in lung tissue were detected by enzyme linked immunosorbent assay (ELISA). The mRNA expressions of TREM2 and caspase-1 were determined by polymerase chain reaction (PCR). The protein expressions of TREM2, caspase-1, Gasdermin-D (GSDMD) were determined by Western blotting. Results:At 2 hours after LIRI, lung injury began to appear, the lung ultrastructure changed, and the lung injury score increased; at 6 hours, the degree of lung injury was the most serious; after 12 hours, the lung injury gradually reduced and the lung injury score gradually decreased. Compared with the normal control group, lung W/D ratio and lung injury score of LIRI 2, 6, 12, 24, 48 hours groups were significantly higher, the differences were statistically significant (lung W/D ratio: 7.06±0.52, 8.34±0.17, 6.42±0.35, 5.34±0.25, 5.59±0.45 vs. 4.69±0.23; lung injury score: 5.50±0.54, 9.75±0.89, 5.88±0.84, 3.63±0.74, 4.13±0.64 vs. 1.13±0.35, all P < 0.05). Compared with the normal control group, the levels of IL-1β and IL-18 in lung tissue were significantly increased at 2 hours after LIRI, reached a peak at 6 hours [IL-1β (ng/L): 502.76±12.25 vs. 56.50±8.07, IL-18 (ng/L): 414.02±10.75 vs. 81.63±5.29, both P < 0.05], then decreased gradually, and were still significantly higher than the normal control group at 48 hours. The PCR and Western blotting showed that the expression of TREM2 was significantly lower than that in the normal control group at 2 hours after LIRI, and reached a valley at 6 hours [TREM2 mRNA (2 -ΔΔCt): 0.47±0.05 vs. 1.02±0.05, TREM2/GAPDH: 0.23±0.13 vs. 0.48±0.17, both P < 0.05], then gradually increased, and reached the peak at 24 hours [TREM2 mRNA (2 -ΔΔCt): 3.98±0.15 vs. 1.02±0.05, TREM2/GAPDH: 0.71±0.17 vs. 0.48±0.17, both P < 0.05]. The trend of expression of caspase-1 and GSDMD were opposite to that of TREM2, which increased at first and then decreased, and reached a peak at 6 hours after reperfusion [caspase-1 mRNA (2 -ΔΔCt): 2.20±0.13 vs. 1.01±0.02, caspase-1/GAPDH: 0.64±0.02 vs. 0.20±0.06, GSDMD/GAPDH: 1.23±0.01 vs. 0.87±0.02, all P < 0.05]. Conclusions:TREM2 might be involved in LIRI in mice. The mechanism may be related to the effect of TREM2 on caspase-1-mediated pyroptosis.

Background: Lung ischemia reperfusion injury (LIRI) is a complex pathophysiological process activated by lung transplantation and acute lung injury. The p38 mitogen-activated protein kinase (MAPK) is involved in breakdown of the endothelial barrier during LIRI, but the mechanism is still unclear. Therefore, we investigated the function of p38 MAPK in LIRI in vivo and in vitro . Methods: Sprague–Dawley rats were subjected to ischemia reperfusion with or without pretreatment with a p38 MAPK inhibitor. Lung injury was assessed using hematoxylin and eosin staining, and pulmonary blood–air barrier permeability was evaluated using Evans blue staining. A rat pulmonary microvascular endothelial cell line was infected with lentiviral expressing short hairpin (sh)RNA targeting p38 MAPK and then cells were subjected to oxygen/glucose deprivation and reoxygenation (OGD/R). Markers of endothelial destruction were measured by western blot and immunofluorescence. Results: In vivo LIRI models showed structural changes indicative of lung injury and hyperpermeability of the blood–air barrier. Inhibiting p38 MAPK mitigated these effects. Oxygen/glucose deprivation and reoxygenation promoted hyperpermeability of the endothelial barrier in vitro , but knockdown of p38 MAPK attenuated cell injury; maintained endothelial barrier integrity; and partially reversed injury-induced downregulation of permeability protein AQP1, endothelial protective protein eNOS, and junction proteins ZO-1 and VE-cadherin while downregulating ICAM-1, a protein involved in destroying the endothelial barrier, and ET-1, a protein involved in endothelial dysfunction. Conclusion: Inhibition of p38 MAPK alleviates LIRI by decreasing blood–air hyperpermeability. Blocking p38 MAPK may be an effective treatment against acute lung injury.