Evaluation of AT-RvD1 in Bacterial Pneumonia

Live gram-negative bacteria (E. coli or P. aeruginosa, 1 × 10⁶ CFU in 25 μl saline) were instilled selectively into the left mainstem bronchus of anesthetized mice (C57bl/6, male, 8–10 weeks; Charles River) as in^{16 (link)}. Mice received AT-RvD1 (100 ng, IV) or vehicle (<0.1% (vol/vol) ethanol in saline) 1 hr after intra-bronchial E. coli or P. aeruginosa. In select experiments, mice received ciprofloxacin (0.2, 2, or 20 mg/kg, IP) or vehicle in addition to AT-RvD1, 1 hr after intra-bronchial E. coli. In separate experiments, animals were treated with AT-RvD1 (100 ng, IB) or vehicle via a repeat tracheostomy surgery 24 and 36 hrs after high-dose intra-bronchial E. coli (2×10⁶ CFU). A high dose of E. coli was used to induce neutrophil infiltration comparable to LPS-induced lung inflammation. In pathogen-mediated acute lung inflammation experiments, animals were treated with E. coli LPS (0.3 mg/kg, 50 μl in saline, IB). In sterile acute lung inflammation experiments, hydrochloric acid (HCl, 0.1N, pH ~1.0, 50 μl IB) was administered as in^{17 (link)}.