Evaluation of the roflumilast effect supplemented with linezolid in pleural empyema in rats caused by intrapleural S.aureus inoculation

In addition to tube drains, pleural empyema is treated with antibiotics and anti-inflammatory drugs. We aimed to evaluate the anti-inflammatory activity of roflumilast combined with linezolid in a rat model of pleural empyema induced by Staphylococcus aureus. A total of 40 rats were divided into 7 groups: sham (n = 4), S. aureus inoculation (n = 6), S. aureus + 10 mg/kg linezolid (n = 6), S. aureus + 5 mg/kg roflumilast (n = 6), S. aureus + 10 mg/kg linezolid + 5 mg/kg roflumilast (n = 6), S. aureus + 10 mg/kg roflumilast (n = 6), and S. aureus + 10 mg/kg linezolid + 10 mg/kg roflumilast (n = 6). Animals were administered linezolid 1 h before and 12 h after inoculation with S. aureus. Roflumilast was administered orally as a single dose 30 min before inoculation with S. aureus. Compared to linezolid treatment alone, linezolid combined with 5 mg/kg roflumilast significantly improved TNF-alpha, IL-1beta, vasodilation/congestion, and tissue/pleural polynuclear leukocyte (PNL) infiltration (p < 0.05). Linezolid combined with 10 mg/kg roflumilast also provided a significant improvement in TNF-alpha, IL-1beta, IL-6, endothelin-1, vasodilation/congestion, mesothelial cell damage, lung tissue PNL, and pleural PNL compared to linezolid alone (p < 0.05). Due to its anti-inflammatory effects and significant impact on recovery, roflumilast can be used in conjunction with antibiotherapy for the treatment of pleural empyema.