Fig. 7: The protective effect of SIRT3 on lung I/R injury partially depends on PKM2.

a–f A549 cells were cotransfected with acetylation site-specific mutants of PKM2 or the negative control (pcDNA3.1) and then subjected to 6 h of hypoxia followed by 2 h of reoxygenation to induce H/R injury. a Cell viability, n = 6. b Representative images of TUNEL staining in A549 cells; the nuclei were stained with DAPI. Scale bar = 200 μm. c The relative number of apoptotic cells is presented as TUNEL-positive cells/DAPI (n = 6). d Caspase-3 activity in living A549 cells. n = 6. e, f FACS analysis of the apoptotic rate in A549 cells. The sum of the annexin V-positive population and propidium iodide-positive population is shown. n = 3. g–m A549 cells were cotransfected with the SIRT3 expression plasmid (pcDNA SIRT3), siRNA targeting PKM2 (si-PKM2) or the corresponding negative control. Then, the cells were subjected to 6 h of hypoxia followed by 2 h of reoxygenation to achieve H/R injury. g Cell viability, n = 6. h Bcl-2 protein level, n = 3. i Representative images of TUNEL staining in A549 cells; the nuclei were stained with DAPI. Scale bar = 200 μm. j The relative number of apoptotic cells is presented as TUNEL-positive cells/DAPI (n = 6). k Caspase-3 activity in living A549 cells. n = 6. l, m FACS analysis of the apoptotic rate in A549 cells. The sum of the annexin V-positive population and propidium iodide-positive population is shown. n = 3. n–s C57BL/6 mice were subjected to 1 h of ischemia followed by 2 h of reperfusion to establish lung I/R injury; mice from the control group underwent sham surgical procedures. PCB2 (30 mg/kg) and/or compound 3 K (10 mg/kg) were injected intraperitoneally once a day for three consecutive days before the operation. n Representative images of H&E-stained lung tissues. Scale bar = 200 μm. Black arrows indicate representative pathological damage. o Histopathological scores (Mikawa’s score) of the lung, n = 6. p–r The W/D ratio, total protein concentration in BALF and caspase-3 activity in the lung, n = 6. s The survival rate of the I/R mice, n = 15. *p < 0.05. Error bars depict the standard deviations.