Figure 4.

Erk activation in mice after LPS inhalation. (A) Mice were injected intraperitoneally with 1 mg of PAK N-terminal peptide, 1 mg of control peptide, or 0.5 ml of UO126 at 70 μM, and then they were treated with saline or LPS as described in Figure 1. At 6 h, the lungs were removed, fixed, and embedded. They then were sectioned and stained for activated Erk by using pT202/pY204 antibody. Small arrows indicate unidentified cells in control lungs that stain positively. Large arrows indicate conduit blood vessels. (B) Mice were treated with saline or LPS, with or without prior injection of 0.5 ml of MEK inhibitor U0126 at 70 μM. At 6 h, leakage of Evans blue dye (EB) was assayed as described in A. Asterisk (*) indicates statistical significance, p < 0.05 relative to LPS-treated mice without UO126; n ≥4. (C) Some mice from the same experiment, described in A were injected with 1 mg/ml PIX blocking peptide, exposed to LPS and sections stained for phospho-Erk. Arrow indicates a conduit vessel.