Figure 4.

Hypoxia-mediated induction of tissue factor expression in murine lung: Egr-1 null mice show reduced tissue factor mRNA (A) and antigen (B–I). (A) Mice (wild-type, +/+, or homozygous null mice, −/−) were subjected to normoxia (N) or hypoxia (H; 6% oxygen), lungs were rapidly harvested, total RNA was prepared, and Northern analysis (30 μg/lane of total RNA) was performed with ³²P-labeled cDNA for mouse tissue factor (Upper) or β-actin (Lower). (B–I) Immunohistochemical analysis for tissue factor antigen was performed on lung tissue from mice exposed to normoxia or hypoxia. (B and C) Hypoxic and normoxic wild-type mouse lung, respectively, stained with antitissue factor IgG. (D and E) Higher-power micrograph of hypoxic wild-type mouse lung stained with anti-tissue factor IgG (D) with an adjacent section stained with antibody to F4/80 to detect mononuclear phagocytes (E). (F and G) Higher-power micrograph of hypoxic wild-type mouse lung stained with anti-tissue factor IgG (F) with an adjacent section stained with antibody to smooth muscle α-actin (G). (H and I) Hypoxic and normoxic egr-1 −/− mouse stained with anti-tissue factor IgG. [×200 (B and C, F–I) and ×600 (D and E).] Results shown are representative of a minimum of three experiments.