Figure 4. Inhibition of fibrin formation and platelet accumulation in wild-type mice as a function of increasing concentrations of bacitracin A.

(A) Fibrin was labeled with a fibrin-specific antibody conjugated to Alexa Fluor 488, and platelets were labeled with Fab fragments of anti-CD41 antibodies conjugated to Alexa Fluor 647. The time course of appearance of fluorescence associated with fibrin (green) and platelets (red) is shown over 180 s following laser-induced vessel wall injury in wild-type mice within the context of the bright-field microvascular histology. Bacitracin A was infused into the circulation 5 min prior to injury at 0, 0.3, 1.5, and 5.0 mg per mouse (columns 1–4, respectively). (B and C) Median integrated platelet fluorescence (B) and median integrated fibrin fluorescence (C) for thrombi formed in the presence of increasing doses of bacitracin A — 0 mg (curve 1; 24 thrombi, 3 mice), 0.3 mg (curve 2; 27 thrombi, 3 mice), 1.5 mg (curve 3; 22 thrombi, 3 mice), and 5.0 mg (curve 4; 20 thrombi, 3 mice) — are presented versus time after vessel wall injury. A representative binarized image is shown in A, and the complete data sets of this and multiple identical experiments are presented in B and C, which plot the integrated fluorescence intensity of all pixels in the image, regardless of their intensity, as a function of time.