Roflumilast, a phosphodiesterase-4 inhibitor, improves hyperoxia-induced lung injury via anti-inflammation

Roflumilast is an inhibitor of phosphodiesterase-4 (PDE4) and can suppress the hydrolysis of cAMP in inflammatory cells, conferring anti-inflammatory effects. This study aimed to investigate the protective effects of roflumilast on hyperoxia-induced acute lung injury (HALI) in a rat model. Male Sprague-Dawley rats were randomly assigned into: control group; HALI group; 2.5 mg/kg roflumilast group; and 5 mg/kg roflumilast group. Rats were pressurized to 250 kPa with pure oxygen to induce lung injury. In the roflumilast groups, rats were orally administered with roflumilast at 2.5 or 5 mg/kg once before hyperoxia exposure and once daily for two days after exposure. Rats were sacrificed 72 hours after hyperoxia exposure. The lung tissues were collected for the detection of lung water content, inflammatory cytokines and NF-κB/p-NF-κB protein expression, and the bronchoalveolar lavage fluid was harvested for the measurement of protein concentration and lactate dehydrogenase activity. Results showed roflumilast at different doses could significantly reduce lung edema, improve lung pathology and reduce the expression of inflammatory cytokines in the lung. The protective effects seemed to be related to the dose of roflumilast. Our study indicates roflumilast has the potential as a medication for the treatment of HALI.