Objective:To determine the oxygen concentration threshold for explosion induced by high-frequency electric knife or argon knife at different energies.Methods:① In vivo experiment The smooth muscle tissue or adipose-rich tissue in 10 pairs of isolated porcine lungs and trachea was electrocauterized at 30 and 50 W with high-frequency electroknife or argon knife at different oxygen concentrations.The initial oxygen concentration was 20%, the oxygen concentration was gradually increased in increments of 5% until the oxygen concentration reached 80%.Each sample was electrocauterized 10 times at each concentration, and the number of explosion was recorded.As long as one explosion occurred, it could be considered that the concentration could induce explosion, and the minimum oxygen concentration inducing explosion was considered as the threshold.② Measurement of oxygen concentration in the airway of patients received bronchoscopic intervention Thirty patients scheduled for elective bronchoscopy with cryotherapy were selected, the oxygen concentration inhaled was reduced from 100% until 50% in decrements of 10%, and the oxygen concentration in airway was measured with the AIRVO 2 transnasal high-flow oxygen inhalation device.ICC consistency analysis was performed between the oxygen concentration in airway and oxygen concentration inhaled. Results:In adipose-rich tissues, the threshold of the oxygen concentration for explosion was 70% at 30 W and 65% at 50 W when using the high-frequency electric knife; the threshold of the oxygen concentration for explosion was 35% at 30 W and 30% at 50 W when using the high-frequency argon knife.In smooth muscle tissues, no explosion occurred at each oxygen concentration when using the high-frequency electric knife and argon knife at 30 or 50 W, and the threshold value was above 80%.There was moderate consistency (ICC value 0.722, 95% CI 0.537-0.850, P<0.001) between the oxygen concentration in airway and oxygen concentration inhaled. Conclusions:In smooth muscle tissues, explosion is not easy to occur at oxygen concentrations below 80% when using the high-frequency electric knife or argon knife.In adipose-rich tissues, explosion is not easy to occur at oxygen concentrations less than 70% at 30 W and at oxygen concentrations less than 65% at 50 W when using the high-frequency electric knife; explosion is not easy to occur at oxygen concentrations less than 35% at 30 W and at oxygen concentrations less than 30% at 50 W when using the high-frequency argon knife.The threshold of oxygen concentrations in airway can be determined using the oxygen concentration inhaled.

Objective:To investigate the effects of long non-coding RNA (lncRNA) Gm13568 on the activation of A1 astrocytes and the progress of experimental autoimmune encephalomyelitis (EAE) in mice.Methods:A recombinant lentiviral vector (LV-Inhibit-Gm13568) carrying astrocyte-specific promoter of glial fibrillary acidic protein (GFAP) was established to inhibit the function of endogenous Gm13568. A control vector (LV-ctrl) was established as well. The recombinant vectors were packaged. C57BL/6 mice were injected with 1×10 7 transforming units of viral suspension via the tail vein and 7 d after the injection, myelin oligodendrocyte glycoprotein 35-55 (MOG 35-55) was used to establish the mouse model of EAE. Four groups, PBS group, EAE group, LV-ctrl+ EAE group and LV-Inhibit-Gm13568+ EAE group, were included in this study. Clinical signs of the mice were monitored daily in a double-blinded manner. The mice were sacrificed 23 d after the EAE model was established and the spinal cord tissues were collected. The expression of Serping 1, C3, Srgn and H2-T23 at mRNA level was detected by real-time PCR. Changes in the expression of IL-6, TNF-α, macrophage chemotactic protein-1 (MCP-1) and interferon-inducible protein-10 (IP-10) were measured. Western blot was used to investigate the expression of GFAP and Notch1 in spinal cord tissues and the phosphorylation of signal transduction and transcription activator 3 (STAT3). The expression of Notch1 intracellular domain (NICD) and GFAP in spinal cord tissues was detected by immunofluorescence. Furthermore, the infiltration of inflammatory cells and the demyelination of spinal cord were observed using HE and Luxol fast blue (LFB) staining methods. Results:Compared with PBS group, A1 astrocytes were activated and Notch1 expression was significantly up-regulated in EAE group and LV-ctrl+ EAE group. The clinical score of mice in LV-Inhibit-Gm13568+ EAE group was decreased from an average score of 3.5 to less than 1 on 23 d after antigen induction and the clinical symptoms were alleviated as compared with the mice in LV-ctrl+ EAE group. Meanwhile, the activation of A1 astrocytes was down-regulated, and the production of inflammatory cytokines and chemokines was also reduced. The expression of Notch1, GFAP and NICD at protein level and the phosphorylation of STAT3 were significantly reduced. Moreover, the infiltration of inflammatory cells and demyelination of spinal cord tissues were alleviated significantly.Conclusions:LncRNA Gm13568 might regulate the activation of A1 astrocytes via the Notch1/STAT3 pathway, thus affecting the production of inflammatory cytokines and chemokines and participating in the process of EAE.