Argon Preconditioning Protects Airway Epithelial Cells against Hydrogen Peroxide-Induced Oxidative Stress

Abstract

Background: Oxidative stress is the predominant pathogenic mechanism of ischaemia-reperfusion (IR) injury. The noble gas argon has been shown to alleviate oxidative stress-related myocardial and cerebral injury. The risk of lung IR injury is increased in some major surgeries, reducing clinical outcome. However, no study has examined the lung-protective efficacy of argon preconditioning. The present study investigated the protective effects of argon preconditioning on airway epithelial cells exposed to hydrogen peroxide (H₂O₂) to induce oxidative stress. Methods: A549 airway epithelial cells were treated with a cytotoxic concentration of H₂O₂ after exposure to standard air or 30 or 50% argon/21% oxygen/5% carbon dioxide/rest nitrogen for 30, 45 or 180 min. Cells were stained with annexin V/propidium iodide, and apoptosis was evaluated by fluorescence-activated cell sorting. Protective signalling pathways activated by argon exposure were identified by Western blot analysis for phosphorylated candidate molecules of the mitogen-activated protein kinase and protein kinase B (Akt) pathways. Results: Preconditioning with 50% argon for 30, 45 and 180 min and 30% argon for 180 min caused significant protection of A549 cells against H₂O₂-induced apoptosis, with increases in cellular viability of 5-47% (p < 0.0001). A small adverse effect was also observed, which presented as a 12-15% increase in cellular necrosis in argon-treated groups. Argon exposure resulted in early activation of c-Jun N-terminal kinase (JNK) and p38, peaking 10- 30 min after the start of preconditioning, and delayed activation of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway, peaking after 60-90 min. Conclusions: Argon preconditioning protects airway epithelial cells from H₂O₂-induced apoptotic cell death. Argon activates the JNK, p38, and ERK1/2 pathways, but not the Akt pathway. The cytoprotective properties of argon suggest possible prophylactic applications in surgery-related IR injury of the lungs.

Intermittent Hypoxia Activates Duration-Dependent Protective and Injurious Mechanisms in Mouse Lung Endothelial Cells

“…3221-20). Twenty-four hours after plating adherent cells were transferred to custom-made boxes [as described in Hafner et al (2016)] and exposed to four different O 2 conditions supplied by premixed gas bottles: (1) 21% O 2 – 5% CO 2 – 74% N 2 ; (2) 0% O 2 – 5% CO 2 – 95% N 2 ; (3) 10% O 2 – 5% CO 2 – 85% N 2 ; (4) 0–21% O 2 oscillations – 5% CO 2 – rest N 2 with a frequency of six oscillations per hour [as described in Wu et al (2016)]. Analysis of cell responses was performed after 4, 24, and 72 h of exposure.…”

A complete review of preclinical and clinical uses of the noble gas argon: Evidence of safety and protection

“…Forty-four preclinical studies were found. [31213141516171819202122232425262728293031323334353637383940414243444546474849505152] The majority ( n = 25) of in vitro and in vivo studies with Ar focused on neuroprotection after a variety of brain damages,[12131415162022242526272829303133343536373839404149] in which different neurological and behavioral tests were combined with histological and biochemical assays. Four studies evaluated the presence of cardioprotective effect after myocardial ischemia/reperfusion (I/R).…”

“…[13171845] Nine studies focused on the preservation of other organs and tissues, such as ex vivo perfused kidney and lung, and culture of human airway epithelium, kidney tubular, and osteosarcoma cells. [192123324647485253] A single study evaluated the influence of Ar inhalation on liver regeneration after partial hepatectomy. [53] Three in vivo studies investigated the effects and the mechanisms of action of Ar under hyperbaric condition.…”

“…Seventeen articles investigated the protective effects of Ar on cell damage [Table 1]. [1718192021222324252627282930313233] In details, two studies were performed in rodent cardiomyocytes, and one of these included also additional investigations in human right atrial appendages obtained from patients undergoing coronary artery bypass or valve replacement surgery;[1718] 9 in rat neurons or hippocampal slices;[242526272829303133] 5 in human cells (neuroblastoma, kidney, airway epithelium, osteosarcoma);[1920212223] and one in whole blood from rodents. [32] One in vitro study investigated whether Ar interacted with tissue plasminogen activator (tPA).…”

“…More specifically, Ar reduced apoptosis in neuronal, tubular kidney, and airway epithelial cells. [192122] As for cardioprotection after I/R, besides increasing cell viability,[18] Ar also diminished early depolarizations in the ventricle tissue, limiting the onset of ischemia-triggered arrhythmias. [17] When Ar was applied on the human right atrial appendages after hypoxia/reoxygenation injury, the recovery of contractile activity was increased.…”