Background: We investigated whether tigecycline (TIGE) is more effective than talc in inducing pleurodesis in rabbits.
Methods: Fifty-six New Zealand rabbits were utilized in a two-phase study: Effects at 14 d (phase I) and at 28 d (phase II) were assessed. Saline solution (SAL n = 3), talc slurry (TALC 200 mg/kg, n = 5), and TIGE at different concentrations (mg/kg): TIGE0.5 (n = 5); TIGE1 (n = 5); TIGE3 (n = 5); TIGE25 (n = 5); TIGE50 (n = 5) were randomly injected, for each phase, through a right chest drainage. TIGE0.5 and TIGE1 were ineffective during phase I and were thus excluded from further investigation. At post mortem examination, pleurodesis was graded grossly and microscopically by three observers blinded to treatment groups.
Results: Phase I: pleurodesis was more effective in TIGE25 and TIGE50 (P < 0.001); TALC was better than TIGE0.5 (P < 0.001), and TIGE1 (P = 0.49), macroscopically. Pleural thickness was significantly higher in TIGE25 compared with SAL, TALC, TIGE0.5, TIGE1, and TIGE3 (P < 0.01). No significant differences were evident between TALC and TIGE3, both macroscopically (P = 0.90) and microscopically (inflammation P = 0.99, fibrosis P = 0.96, pleural thickness P = 0.99). Phase II: better effectiveness of TIGE50 compared with all other groups (P < 0.001) except TIGE 25 (P = 0.29); results similar to phase I for TALC and TIGE3 (P = 0.99), macroscopically. Microscopically greater inflammation in TALC compared with TIGE3 (P < 0.05) and in TIGE50 to TIGE3 (P = 0.05). Significant complications occurred in all TIGE50 group. One of TIGE25 and one of TIGE50 died of respiratory distress and of right hemothorax+ascites, respectively.
Conclusions: Intrapleural TIGE3 mg/kg is as effective as talc in inducing pleurodesis in rabbits. The intrapleural TIGE toxicity threshold was reached at TIGE25 mg/kg concentration.
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