Dynamic changes in apoptosis of polymorphonuclear neutrophil in rabbit with acute lung injury induced by seawater drowning / 解放军医学杂志

ABSTRACT

Objective To explore the dynamic changes in apoptosis of polymorphonuclear neutrophil (PMN) during the course of seawater drowning-induced acute lung injury (SWD-ALI), and the possible roles of cytokines in the process. Methods Thirty-six NZ rabbits were randomly divided into 6 groups by using a random number table control group (0h, as baseline value) and 5 seawater drowning groups (S1h, S3h, S6h, S12h and S24h). Blood gas analysis and hemogram were observed at different time points. The ratio of wet to dry lung weight (W/D) and lung permeability index (LPI) were calculated. The changes in PMN apoptosis were analyzed by flow cytometer. The concentrations of tumor necrosis factor alpha (TNF-?), interleukin-1 (IL-1 ) and IL-10 in serum were detected by ELISA. Meanwhile, the pathological changes in lung tissue were examined with hematoxylin-eosin (HE) staining, and lung pathologic scores (LPS) were evaluated. Results The W/D ratio reached its peak value at 3h, while LPI at 6h. The histopathologic findings indicated that inflammatory cell infiltration was most massive at 6～12h. LPS increased at 1h, significantly higher than that of control group (P0.05). Conclusions The apoptosis of PMN, the main inflammatory effector cells, is significantly inhibited in the early stage of SWD-ALI. The serum cytokines, TNF-?, IL-1 and IL-10, play important roles in the pathogenesis of SWD-ALI, but have no evident effects on the inhibition of PMN apoptosis.