FIG. 4.

Fibrinogen suppresses TDM-induced neutrophil necrosis in vitro. Bone marrow-derived neutrophils were purified and stimulated by TDM, vehicle control (n-hexane), or 60 μM staurosporine for 2 h in the presence or absence of 500 μg/ml fibrinogen and then stained using propidium iodide (PI) and annexin V to determine the percentage of the neutrophil population that is necrotic or apoptotic, respectively, by flow cytometry. (A) TDM induces a significantly higher percentage of PI-positive cells above that of the vehicle (n-hexane) control, and this percentage is significantly reduced in the presence of fibrinogen. (B) Staurosporine-induced neutrophil apoptosis, but not necrosis, also is significantly reduced in the presence of fibrinogen. Data from triplicate samples from a representative experiment are shown as means ± standard deviations, and asterisks indicate statistically significant differences (P < 0.05).