Fig. 2

Evidence of PMVEC apoptosis 4 h following CLP-sepsis in mice in vivo. a PMVEC in ex vivo lung tissue sections were labeled with a specific marker (CD31; left column of panels; red). Activated caspases were identified by labeling with FLIVO (middle column of panels; green). Compared to sham mice in which only a few PMVEC stained positive for activated caspases, CLP-sepsis markedly increased the number PMVEC with activated caspases (overlay; right column of panels). b Compared to sham mice, CLP-sepsis was associated with increased PMVEC apoptosis as identified using three complementary markers: FLIVO (activated caspases), Annexin V (surface phosphatidyl serine presence), and TUNEL (DNA fragmentation). At 4 h following CLP-sepsis, FLIVO+ PMVEC (green) were almost uniformly also Annexin V+ (left column of panels), and were largely but not always TUNEL+ (right column of panels). Scale bar = 20 μm