Role of pulmonary microvascular endothelial cell apoptosis in murine sepsis-induced lung injury in vivo

摘要: Sepsis remains a common and serious condition with significant morbidity mortality due to multiple organ dysfunction, especially acute lung injury (ALI) respiratory distress syndrome (ARDS). Sepsis-induced ALI is characterized by dysfunction of the pulmonary microvasculature microvascular endothelial cells (PMVEC), resulting in enhanced sequestration infiltration polymorphonuclear leukocytes (PMN) as well disruption normal alveolo-capillary permeability barrier leak albumin-rich edema fluid into interstitium alveoli. The role PMVEC death specifically apoptosis septic vivo has not been established. In murine cecal ligation/perforation (CLP) model sepsis, we quantified correlated time-dependent changes Evans blue (EB)-labeled albumin (1) (propidium iodide [PI]-staining) both fluorescent intravital videomicroscopy (IVVM) histology, (2) using histologic microscopic assessment panel 3 markers: cell surface phosphatidylserine (detected Annexin V binding), caspase activation FLIVO labeling), DNA fragmentation (TUNEL labeling). Compared sham mice, CLP-sepsis resulted increased EB-albumin leak, (PI+ staining) early 2 h more marked 4 h after CLP. Septic also exhibited presence all markers (Annexin V+, FLIVO+, TUNEL+) 30 mins – 1 h CLP-sepsis, which similarly markedly until 4 h. albumin-permeability were highly (PI+; r = 0.976, p < 0.01) (FLIVO+; r = 0.991, p < 0.01). Treatment pan-caspase inhibitor Q-VD prior CLP reduced death/apoptosis attenuated including PMN (p < 0.05). abrogated following mice deficient iNOS (Nos2 −/− ) or NADPH oxidase (p47 phox−/− gp91 wild-type treated inhibitor, apocynin. death, mediated through caspase-dependent iNOS/NADPH-oxidase dependent signaling.