Evaluation of the Roflumilast Effect Supplemented with Linezolid in Pleural Empyema in Rats Caused by Intrapleural <i>Staphylococcus aureus</i> Inoculation

Abstract

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-α, IL-1β, 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-α, IL-1β, 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.