Paracetamol and ibuprofen block hydrothorax absorption in mice†

OBJECTIVES: Non-steroidal anti-inflammatory agents (NSAIDs) and paracetamol alter pleural permeability, hindering pleural fluid recyc-ling. The aim of this study was to investigate the effect of different analgesic and anti-inflammatory agents on fluid recycling in an induced hydrothorax model in mice. METHODS: Hydrothorax was induced in C57BL/6 mice by injecting 500 μl phosphate-buffered saline–bovine serum albumin 1 % isosmotic in the right hemithorax. Paracetamol (1 g/kg), ibuprofen (250 mg/kg) and parecoxib (2 mg/kg) were administered systematically by intra-peritoneal injections. Each drug group included eight mice, which were sacrificed at 2 h and 4 h, respectively, after injections. The remain-ing hydrothorax volume and total cells contained were determined. RESULTS: Regarding the paracetamol and ibuprofen groups, the remaining hydrothorax volume was greater than in the control group (350 ± 61, 348 ± 62 and 270 ± 51 μl, respectively, P = 0.042) when mice were sacrificed within 2 h. Similar observations were made in groups sacrificed after 4 h (202 ± 45 and 198 ± 44 vs 107 ± 56 μl, respectively, P = 0.002). In the parecoxib group, the remaining hydrothorax volume was 122 ± 53 μl (P = 0.038 versus paracetamol and ibuprofen, P> 0.05 versus control group). At the same time, the absorption rate in the paracetamol and ibuprofen groups was lower than in the parecoxib and control groups (P = 0.033). In the parecoxib group, the ab-sorption rate was lower than that in the control group after 2 h (P = 0.042). In the paracetamol and ibuprofen groups, the total cell coun