Age-dependent coagulation during endotoxemia. (A) Western blot analysis of a time course experiment examining fibrin formation in lung, kidney, and liver of young (4 months) and aged (24 months) mice that were sacrificed 6 and 12 hours after LPS injection (2.5 mg/kg, intraperitoneal). The control mice without LPS injection are represented by 0 h. Each lane contained 40 μg of protein derived equally from 5 individual mice. Each membrane was reprobed with anti–β-actin antibody to assure equal protein loading. (B) Densitometric analysis of panel A. (C) Fibrin formation 12 hours after LPS injection was further compared among individual samples, which were pooled in panel A. Each lane contained 40 μg of protein from an individual mouse. (D) Densitometric analysis of panel C. (E) Western blot analysis comparing thrombosis in lungs from young mice with a high dose of LPS (20 mg/kg) and aged mice with a low dose of LPS (2.5 mg/kg; n = 4 in each group). Each lane represents a protein sample from an individual mouse. (F) Densitometric analysis of panel E. (D-F) Data are mean ± SD. *Statistical significance (P < .05). **Statistical significance (P < .01).