Sevoflurane preconditioning and postconditioning attenuate apoptosis induced by ischemia-reperfusion in rat lung

Objective To investigate the effect of sevoflurane preconditioning and postconditioning on lung ischemia-reperfusion(IR) injury and apoptosis in rat.Methods Wistar rats were randomly assigned to four groups:sham group(n =6):no ischaemia-reperfusion;IR group(n =6):left lung ischemia was achieved by clamping the hilum for 90 min,followed by 120 min reperfusion;sev+pre group(n =6):1 minimum alveolar concentration(MAC) sevoflurane was admi-nistered for 30 min prior to ischemia;sev+post group(n =6):ischemia was followed by 1 MAC sevoflurane postconditioning at the first 30 min reperfusion.PaO2 was measured after reperfusion.The number of apoptotic cells was estimated using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling(TUNEL) technique.Results After ischemia-reperfusion,a significant deterioration of PaO2 was noticed and the number of apoptotic cells remarkably increased compared with that of sham group.In sev+pre group and sev+post group,PaO2 was(85.7±14.4) mmHg and(88.6±12.5) mmHg respectively,which was apparently increased compared with that in IR group [(63.9±11.3) mmHg,P <0.05].The number of apoptotic cells in sev+pre group [(6.94 ± 1.49)%] and sev+post group [(7.69 ± 1.61)%] was significantly lower than that in IR group [(12.12 ± 2.77)%,P <0.05].But all parameters showed no significant difference between sev+pre group and sev+post group.Conclusions Both sevoflurane preconditioning and postconditioning could prevent lung ischemia-reperfusion injury and attenuate apoptosis in rat.

Single-cell immune profiling reveals distinct immune response in asymptomatic COVID-19 patients

While some individuals infected by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)present mild-to-severe disease,many SARS-CoV-2-infected individuals are asymptomatic.We sought to identify the distinction of immune response between asymptomatic and moderate patients.We performed single-cell transcriptome and T-cell/B-cell receptor(TCR/BCR)sequencing in 37 longitudinal collected peripheral blood mononuclear cell samples from asymptomatic,moderate,and severe patients with healthy controls.Asymptomatic patients displayed increased CD56^(bri)CD16^(-) natural killer(NK)cells and upregulation of interferon-gamma in effector CD4^(+) and CD8^(+) T cells and NK cells.They showed more robust TCR clonal expansion,especially in effector CD4^(+) T cells,but lack strong BCR clonal expansion compared to moderate patients.Moreover,asymptomatic patients have lower interferon-stimulated genes(ISGs)expression in general but large interpatient variability,whereas moderate patients showed various magnitude and temporal dynamics of the ISGs expression across multiple cell populations but lower than a patient with severe disease.Our data provide evidenee of different immune signatures to SARS-CoV-2 in asymptomatic infections.