We have previously shown that talc (TL) induces an acute systemic inflammatory response even in doses considered ineffective (100 mg/kg) in producing pleurodesis. Silver nitrate (SN) has been used as an effective pleurodesis agent, but its systemic effects are still unknown. The aim of this study was to determine the systemic response to SN in doses considered effective (0.5%) and ineffective (0.1%) in an experimental model of pleurodesis and compare with the findings previously described with talc.
Groups of six rabbits were injected intrapleurally with TL 100 or 400 mg/kg and SN 0.1% or 0.5% and after 6 and 24 hours samples of blood were assayed for leukocytes (WBCx103), percent neutrophil and the inflammatory cytokines interleukin-8 (IL-8; pg/mL) and vascular endothelial growth factor (VEGF; pg/mL). Pre-injection blood samples were used as controls. Statistics: ANOVA (all groups compared to control).
The WBC increased at 6 hours for both agents only for the higher doses and decreased after 24 hours. The percent neutrophils increased at 6 hours in the TL100 and TL400 groups, but not in the SN0.1% and SN0.5% groups. The IL-8 and VEGF levels were greater for all groups at all times, even in doses considered ineffective in producing pleurodesis.
Intrapleural SN induced an acute systemic inflammatory response characterized by a low cellular response when compared to talc. 6 hours24 hoursControlTL100TL400SN0.1SN0.5TL100TL400SN0.1SN0.5WBC5.1± 1.6*7.6± 2.19.7± 3.65.8± 1.08.1± 2.14.7± 1.36.8± 3.17.7± 1.96.7± 1.2%N53± 6*74± 973± 1039± 25*60± 1261± 545± 1139± 736± 13IL-890± 31*890± 390620± 3801955± 3652250± 3071461± 610955± 515990± 2451512± 510VEGF< 15*65± 3552± 1533± 1447± 1366± 4356± 6.048± 1453± 9.0
WBC: *p< 0.05 TL400 6hours vs. Control; SN0.5 6hours vs. Control.
%N *p< 0.05 TL100 and TL400 6hours vs. Control; SN0.5 6hours vs. Control.
IL-8: *p< 0.05 TL100 and TL400 at all times vs. Control; *p< 0.001 SN0.1 and SN0.5 at all times vs. Control.
p< 0.05 All groups of TL and SN at all times vs. Control.
E. Marchi, None.